Unlock the Code of MHC II-enabled Cancer Immunotherapy

The Major Histocompatibility Complex Class II molecules (MHC II) have the ability to present tumor antigens to CD4+ T cells, playing a critical role in initiating anti-cancer immunity. Recently, the discovery that MHC II is expressed on many atypical antigen-presenting cells (APCs) has exponentially increased interest in MHC II as a potential target for immunotherapy. Tumor immunotherapies targeting MHC II aim to enhance the sensitivity of tumors to CD4+ T-cell-mediated immune responses by increasing MHC II expression in tumor cells, especially in those traditionally classified as ”cold tumors”-tumors with insufficient T cell infiltration. In clinical studies, MHC II-based personalized vaccines, immune checkpoint blockade (ICB) therapy, and combination immunotherapies have yielded encouraging results.In this review, we describe the intricate cancer immunomodulatory network centered around on MHC II expression on both professional and atypical APCs, highlighting the challenges and opportunities for related immunotherapies. In addition, we analyze how the prediction of MHC II as tumor markers and their specific binding affinities can guide the development of precision medicine to address the unique complexity of each type of cancer. Unlock the Code of MHC II-enabled Cancer Immunotherapy Jiaqi Liu, 1, Xueru Song, 1 *, Wenqi Guo, 1, Wanyi Liu, 2, Shaokang Xu, 3, Xiaoyuan Chu, 1 * *, Zengjie Lei, 1 * * * Affiliations 1. Department of Medical Oncology, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210000, China 2. Department of Medical Oncology, Nanjing Jinling Hospital, Nanjing University of Chinese Medicine, Nanjing 210000, China. 3. Department of Medical Oncology, Nanjing Jinling Hospital, Nanjing Medical University, Nanjing 210000, China

MHC II; professional antigen-presenting cells; atypical antigen-presenting cells; tumor immunotherapy.

The Major Histocompatibility Complex Class II molecules (MHC II) have the ability to present tumor antigens to CD4 + T cells, playing a critical role in initiating anti-cancer immunity. Recently, the discovery that MHC II is expressed on many atypical antigen-presenting cells (APCs) has exponentially increased interest in MHC II as a potential target for immunotherapy. Tumor immunotherapies targeting MHC II aim to enhance the sensitivity of tumors to CD4 + T-cell-mediated immune responses by increasing MHC II expression in tumor cells, especially in those traditionally classified as ”cold tumors”-tumors with insufficient T cell infiltration. In clinical studies, MHC II-based personalized vaccines, immune checkpoint blockade (ICB) therapy, and combination immunotherapies have yielded encouraging results. In this review, we describe the intricate cancer immunomodulatory network centered around on MHC II expression on both professional and atypical APCs, highlighting the challenges and opportunities for related immunotherapies. In addition, we analyze how the prediction of MHC II as tumor markers and their specific binding affinities can guide the development of precision medicine to address the unique complexity of each type of cancer.

Cancer immunotherapy has made remarkable progress in recent years; however, challenges remain, including immune escape by tumor cells, immunosuppression of the tumor microenvironment (TME), and resistance to immune checkpoint blockade therapies (ICBs) in most patients, which limit the broader application of immunotherapy across a wider range of tumor types 1 . Abnormal expression of the major histocompatibility complex (MHC) allows tumor cells to evade the immune surveillance and attack, which is a key factor contributing to the ineffectiveness of immunotherapy. One common mechanism of immune escape of tumor cells is the downregulation of MHC, which enables them to evade T cell recognition 2,3 . In addition, MHC also plays a role in regulating immune cell activity in the TME 4 . Among them, MHC II is a key class of molecules in the immune system, mainly found on the surface of antigen-presenting cells (APCs). In the context of cancer, the primary function of MHC II is to bind tumor antigenic peptides and present them to CD4 + T cells. These process not only plays a critical role in initiating the immune response, but also promotes the formation of immune memory, enhancing long-term anti-tumor immunity 5 . Obviously, MHC II plays an important role in the field of tumor immunotherapy. Therefore, an in-depth study of MHC II can facilitate the development of more effective immunotherapies, ultimately benefiting a broader range of cancer patients. The expression and regulation of MHC II in the cancer immune network are being increasingly understood as research advances. In the TME, the degree and pattern of MHC II expression can serve as a marker for various immune cell subtypes. The expression of MHC II on professional APCs is essential to the functioning of the immune system. Professional APCs include dendritic cells (DCs), monocyte-macrophages, and activated B cells. However, the expression of MHC II is not limited to professional APCs, but also in atypical APCs, such as tumor cells, cancer-associated fibroblasts (CAFs), regulatory T cells (Tregs), and neutrophils, which are capable of processing and presenting tumor antigens restricted to MHC II. An in-depth exploration of MHC II expression and function on atypical APCs will broaden our understanding of tumor immune escape mechanisms and responses to immunotherapy. The regulation of MHC II molecule expression is a multifaceted process that involving various cytokines in the TME, transcriptional regulation and post-transcriptional modifications of intracellular MHC II genes, as well as the metabolic state of the tumor. These mechanisms do not function in isolation but are closely intertwined, interacting to form a complex network of MHC II expression. Based on this, the importance of MHC II in cancer immunotherapy is emphasized, especially in the development of personalized tumor vaccines and combination immunotherapy 6-9 . Recently, researchers have conducted extensive studies on MHC II in tumor immunity, including the identification of MHC II-restricted antigens to provide targets for vaccine design 6,7 . The expression and antigen presentation efficiency of MHC II on antigen presenting cells can be improved through genetic engineering or pharmacological interventions 8,10-13 . In the TME, overcoming the immunosuppressive state by restoring or enhancing the antigen presenting function of MHC, along with combining MHC II-related immunotherapy with other immunomodulators, can improve the efficacy 14,15 . In this article, we first review the structure and distribution of MHC II, then focus on its expression and regulation in both professional and atypical APCs, and summarize the current MHC II-related cancer immunotherapy strategies. At the end of the paper, we explore the potential of MHC II as a tumor marker and discuss the opportunities and challenges in predicting MHC II-peptide interactions and identifying T cell receptors (TCRs) with MHC II epitopes. This review not only fills the gap in systematic summaries on the role of MHC II in tumor immunity, but also integrates recent studies to provide a theoretical foundation for the application of MHC II in tumor immunotherapy, thereby inspiring new research directions. Structure and distribution of MHC II Structure of MHC II MHC II are transmembrane glycoprotein heterodimers composed of two non-covalently linked polypeptide chains, known as the α-chain and β-chain, with molecular weights of approximately 34 kD and 29 kD, respectively. Both chains are embedded in the cell membrane and extend into the cytoplasm. The α- and β-chains each contain two immunoglobulin-like functional regions in their extra domains, labeled as the α1 and α2 on the α-chain, and β1 and β2 on the β-chain. Together, the α1 and β1 functional regions form a groove structure, which serves as the peptide-binding region used for antigenic peptides, while the α2 and β2 functional regions contribute to molecule stabilization and facilitate interactions with T-cell receptors. The gene and protein structures of MHC II is depicted in Fig. 1. MHC I consists of an α-chain and β2-microglobulin. The α-chain contains a peptide-binding region formed by the α1 and α2 domains, with the ends of this region bounded by specific amino acid residues. This structure creates a relatively closed peptide-binding groove that restricts the length of the bound peptide, typically accommodating segment of 8-11 amino acid residues. Unlike MHC I, the peptide-binding region of MHC II is open at both ends, allowing it to accommodate longer peptides, typically 12 to 16 amino acid residues 16 . This open binding groove enables MHC II to bind peptides derived from lysosomal breakdown of exogenous antigens, such as those secreted from bacteria, viruses, and tumor cells 17,18 . When homologous peptide-MHC Class II complexes are recognized by the TCRs on the surface of CD4 + T cells, the TCR-CD3 complex undergoes clustering and its intracellular region is phosphorylated by the lymphocyte-specific protein-tyrosine kinase (LCK). This process activates the tyrosine motif by phosphorylating the immune receptor, which further triggering signal transduction, facilitating interaction between zeta chain of T cell receptor associated protein kinase 70 (ZAP-70) and CD3ζ and ultimately leading to the activation of CD4 + T cells 19,20 . Distribution of MHC II Human and mouse MHC II share significant similarities in gene coding, molecular structure, function, etc. These similarities reflect the evolutionary conservation of MHC II and their importance in immune response. However, due to species-specific biological differences, MHC II differs in certain variations that may affect its interaction with specific antigens or TCRs. Therefore, these differences need to be taken into account in studies, especially when extrapolating findings from mouse models to human (Table 1). The MHC II gene is highly polymorphic 21 . In humans, three major gene loci encode MHC II-HLA-DR, HLA-DP and HLA-DQ-all located on chromosome 6. The three types of MHC II encoded by those loci have distinct requirements for the shape and chemical properties of binding peptides, due to variations in the amino acid sequences of their α1 and β1 domains. Compared to HLA-DR and HLA-DQ, HLA-DP has a more restricted range of binding peptides, and the cellular expression patterns of HLA-DR, HLA-DP and HLA-DQ are also different. HLA-DR is primarily expressed on professional APCs, whereas HLA-DP and HLA-DQ have a broader expression profile 22 . In addition, atypical MHC II molecules include HLA-DM and HLA-DO. The proteins encoded by the HLA-DM genes facilitate the loading of antigen peptides into the antigen-binding groove of MHC II, while the proteins encoded by the HLA-DO genes are considered negative regulators of HLA-DM function. In the context of cancer, MHC II is mainly expressed on professional APCs (e.g., B cells, DCs, macrophages). In the TME, the expression levels and patterns of MHC II can serve as markers to distinguish various immune cell subsets. Their expression on different APCs provides essential biological information for the development of more effective tumor immunotherapy regiments. In addition, increasing attention has been given to MHC II expression atypical APCs, such as hematopoietic and solid tumor cells, tumor fibroblasts, tumor lymphatic endothelial cells, and neutrophils. Expression of MHC II on professional APCs The expression of MHC II on professional APCs is central to immune system function. Professional APCs include DCs, monocyte-macrophages, and activated B cells. These cells present antigens to CD4 + T cells via MHC II, a key step in initiating the adaptive immune response. Understanding the mechanisms underlying the efficient production and maintenance of peptide-MHC II complexes in APCs provides a basis for elucidating T cell function in both healthy and cancerous states. DCs DCs can internalize extracellular substances through macro pinocytosis and are highly efficient APCs 23 . Immature DCs exhibit strong phagocytosis ability. Prior to cell activation, a large number of MHC II proteins are present in the endosomal lysosomal antigen processing compartment 24 . Toll-like receptor (TLR) ligands, such as lipopolysaccharide, unmethylated Cytosine-phosphate-Guanine (CpG) DNA fragments and Poly (I:C) can further activate DCs. This leads to significant changes in MHC II expression and cellular localization in DCs 25,26 . In mature DCs, the vast majority of MHC II exist on the plasma membrane. Current studies indicate that the changes in the localization of MHC II in DCs before and after activation are primarily driven by the following factors: immature DCs internalize external antigens, and encapsulating them with endosome. When the endosome binds to the lysosome, the protein is degraded into peptides, which then bind to MHC II in the acidic environment 27-29 . Following cell activation, MHC II biosynthesis is increased 30,31, and its stability is improved 28,31 . Elongated tubules 32,33 or tubule-derived vesicles produced by the antigen processing compartment are transported from the cell to the plasma membrane 28,32-34 . The mechanism by which APCs processes and presents antigens to CD4 + T cells through MHC II is depicted in Fig. 2. CD86 on antigen-loaded DCs binds to CD28 on antigen-specific CD4 + T cells, providing a co-stimulatory signal that drives the transport of the peptide-MHC II complex from the tubule to the immune synapses formed between DC and T cells, thereby activating CD4 + T cells. It secretes cytokines and chemokines, such as IL-2 and interferon gamma (IFN-γ), which directly exert cytotoxic effects to attack tumor cells or recruit other immune cells, such as macrophages and natural killer cells (NK), to promote the anti-tumor immune response 34 .In most cases, DCs expressing MHC II typically play an anti-tumor role. However, in ovarian cancer, regulatory DCs (MHC II + DEC205 + CD11c + CD14 - )-despite being highly expressed-contribute to tumor progression due to their ability to secrete immunosuppressive cytokines and promote tumor angiogenesis 35,36 . Macrophage As one of the major immune cell components in the TME, macrophages exhibit high plasticity and can undergo phenotypic transformation in response to changes in the TME, playing a complex role in the occurrence, progression, invasion and metastasis of tumors 37,38 . Tumor associated macrophages (TAM) are pleiotropic cells with both M1 and M2 characteristics 39 . Many studies have shown that macrophages are a heterogeneous population of cells whose phenotypic characteristics and functions are shaped by their cytokine environment. M1 macrophages exhibit pro-inflammatory response and inhibit tumor growth, whereas M2 macrophages, on the contrary, display an anti-inflammatory response and promote tumor progression 40,41 . The high expression of MHC II on TAM indicates polarization toward the M1 phenotype 42 . For example, in prostate cancer, both MHC II expression and the frequency of M1 TAMs are increased, and these activated TAM are positively correlated with tumor growth control 43 . In contrast, in multiple myeloma (MM), the expression of MHC II on CD14 + monocytes-the precursors of TAMs-is reduced, leading to M2 polarization of macrophages and subsequent inhibition of T cell function 44 . Activated B cells Although B cells mainly present antigens to CD8 + T cells via MHC I, they can also express MHC II upon activation, thereby participating in antigen presentation to CD4 + T cells. This cross-presentation is essential for the further activation of B cells and subsequent antibody production. Compared to other professional APCs, MHC II proteins are rarely found in endosomes of resting B cells 45 . Specific B cell receptor (BCR) signaling induces the targeting of MHC II and BCR-associated antigens to late endosomes and lysosomes of B cells, a process dependent on the rearrangement of the microtubule organizing center of B cells. Lysosomes containing MHC II are recruited into immune synapses 46, where they acidify the immune synapses and releases proteolytic enzymes to process antigens. This generates peptide-MHC II complexes of varying conformations 45,47, which are then presented to antigen-specific CD4 + T cells. In gastric cancer, mature tertiary lymphoid structures (mTLS) primarily consist of B cell subsets at various stages of differentiation. Compared to immature tertiary lymphoid structures (iTLS), mTLS express higher levels of MHC II. Tumors with mTLS also contain more plasma cells and CD8 + T memory cells, and also show less abdominal metastasis. This suggests that the expression of B cell MHC II in mTLS may be generally associated with improved patient prognosis and better outcomes from immunotherapy 48 . However, experiments have revealed that due to limitations in MHC II expression, myeloid APCs remain the primary drivers of tumor-specific CD4 + T cell activation. The activation capacity of tumor-specific B cells is highly limited, even in the context of significantly reduced lymphocyte populations 49 . B cells are an ideal target for anti-tumor therapy because they can be easily purified from peripheral blood of patients. However, this study suggests that future anti-tumor therapy involving activated B cells may still require combination with other methods of immune cell activation to achieve better efficacy. Expression of MHC II on atypical APCs The expression of MHC II on atypical APCs has multiple implications for cancer, including enhancing the tumor antigen recognition, further promoting anti-tumor immune response, influencing tumor prognosis, and serving as a potential predictive biomarker. It also provides new targets for immunotherapy. Understanding the expression of MHC II on atypical APCs and further investigating the functional effects of tumor-specific MHC II (tsMHC II) will yield new insights into the complex cancer immunomodulatory network. Tumor Cells MHC II expression by tumor cells has been reported in various human malignancies, including melanoma 50-53, breast cancer 54-57, colorectal cancer 58,59, ovarian cancer 60-62, pancreatic cancer 63, non-small-cell lung cancer 64-66, and classical Hodgkin’s lymphoma 67,68, etc (Table 2). MHC II expression on tumor cells affects the T cell infiltration within tumors. Recent studies have found that MHC II expressed on olfactory neuroblastoma (ONB) tumor cells drives T cell infiltration into the tumor parenchyma rather than the mesenchyme. Consequently, increased MHC II expression facilitates tumor cell surveillance 69 . Expression of MHC II on tumor cells is characteristic of a particular subpopulation involved in T cell-mediated inflammatory and immune responses in solid tumors. Some tumor cells can function independent of professional APCs, using MHC II to present endogenous antigens directly to CD4 + T cells 70, promoting CD4 + type 1 helper T cells (Th1) differentiation, and generating antigen-specific cytotoxic CD4 + T cells. For example, HPV + oropharyngeal squamous cell carcinoma cells can activate CXCL13 + CD4 + T cells in this manner 71, which display characteristics of both follicular helper T cells (TFH) and Th1 72 . tsMHC II has also been associated with a reduction in tumor lymphatic metastasis, enhanced expression of genes related to IFN pathway activation, and increased levels of anti-tumor factors. Several studies have demonstrated a positive correlation between tsMHC II and favorable prognosis in various cancer subtypes 73-75 . The expression level of MHC II varies significantly across different tumor cells. Some tumor cells recruit immunosuppressive cells through high expression of MHC II, thereby suppressing the immune-activated state of the tumor. Homologous recombination deficiency (HRD), a condition of genomic instability that impairs DNA repair, is common in many cancers, especially ovarian cancer. In HRD tumors, the proportion of IFN-responsive tumor cells is positively correlated with the proportion of effector regulatory T cells (eTregs) in the tumor, and IFN helps upregulate MHC II expression on the surface of tumor cells. This suggests that tumor cells may recruit or activate eTregs through the high expression of MHC II and co-suppressor molecules 76 . In contrast, some tumor cells reduce their immunogenicity through low expression of MHC II, which is conducive to cancer cell survival. For example, genome-wide duplication (WGD) frequently occurs in high-grade serous ovarian cancer (HGSC) 77,78 . Due to genomic instability, cancer cells with WGD tend to have a higher mutation burden 79,80, resulting in a higher neoantigen burden and stronger immunogenicity. However, within the tumor cell subsets of WGD, immune escape is achieved by reducing the expression of MHC II 62 . CAFs The antigen-presenting CAF (apCAF), a subgroup of CAFs, expresses MHC II-related genes. Unlike professional APCs, apCAFs lack the co-stimulatory molecules required to induce T cell proliferation 81 . Therefore, it is speculated that MHC II expressed by apCAFs may act as a decoy receptor to inactivate CD4 + T cells by inducing anergy or promoting their differentiation into Tregs. In this case, apCAFs weaken anti-tumor immunity. Therefore, apCAFs may contribute to the immunosuppression nature of the TME. Different subgroups of CAFs can transition between states through specific signaling pathways, with apCAFs representing a dynamic cellular state of CAFs. At present, it has been found that apCAFs can transdifferentiate into myoblast CAFs (myCAFs) or inflammatory CAF (iCAFs). Both myCAFs and iCAFs promote tumor growth, invasion and metastasis by secreting extracellular matrix, growth factors and inflammatory factors 82 . The dynamic plasticity of apCAFs also suggests potential for conversion and therapeutic utilization, allowing for transformation of the three cancer-promoting CAFs (pCAFs) into cancer-restraining CAFs (rCAFs) 83-86 . Alternatively, this plasticity could be harnessed to enhance the activity of antitumor CAF 87 . rCAFs have been identified in colorectal cancer, bladder cancer, pancreatic ductal adenocarcinoma (PDAC) and other tumor types. Although the mechanism by which apCAFs are converted to rCAFs remains unclear, further research is currently needed to identify the intratumoral signals that induce the formation and activation of apCAFs, as well as to clarify the role of each CAF subtype. Current research on apCAFs mainly focus on PDAC, and further studies are needed to validate these findings in other cancer types. Other Cells By recognizing antigenic peptides presented by MHC II, CD4 + T cells can differentiate into various effector cells, including Th1, type 2 helper T cells (Th2), type 17 helper T cells (Th17) and Tregs, each with distinct functions that collectively help maintain immune balance. Tregs are highly plastic cells that actively adapt to their microenvironment. In human tumors, invasive Tregs selectively overexpress CD74, the invariant chain of MHC II. CD74 increases Tregs accumulation and stabilizes their suppressive phenotype by modulating membrane trafficking, cytoskeleton, cell connectivity, and transcriptional activity 88 . Neutrophils have been shown to cross-activate CD4 + and CD8 + T cells 89-91 and are mainly divided into 10 subgroups. Among these, only the HLA-DR + CD74 + subgroup shows high expression of MHC II, making it one of the most enriched subgroups in cancer. This subgroup also a key anti-tumor neutrophil subgroup in most cancer types and is associated with the most favorable prognosis. However, HLA-DR + neutrophils exhibit a cancer type preference, with relatively greater enrichment in non-small cell lung cancer (NSCLC), bladder cancer, and ovarian cancer, while their infiltration is reduced in renal cell carcinoma (RCC) and oral squamous cell carcinoma (OSCC) 92 . Neutrophils can exhibit diverse phenotypic responses to environmental cytokines and chemokines, playing opposite roles in different cancers. For example, stimulation of neutrophils with granulocyte macrophage colony stimulating factor (GM-CSF) 93, anti-FC-riIB-antigen conjugate 94, etc., triggers the acquisition of APC-like properties, and upregulates the expression of MHC II, CD80, and CD86. Conversely, exposure to transforming growth factor β(TGF-β) in the immunosuppressive TME causes neutrophils to adenosinept an immunosuppressive phenotype. However, compared to other APCs, neutrophils demonstrate earlier migration to inflammatory sites, along with active phagocytic and chemotactic characteristics. Their short half-life may minimize the risk of being reprogrammed by TME into immunosuppressive cells 95 . These unique advantages highlight the potential value of neutrophils in anti-tumor immune responses. Regulation of MHC II expression The expression and regulation of MHC II involve multiple aspects. The relevant factors in the TME, the transcriptional and post-transcriptional modification of MHC II genes in cells, and the tumor metabolic environment all have an impact on the expression of MHC II. Moreover, the regulatory mechanisms are not independent; rather, they are related and interact to form a complex network governing MHC II expression and regulation. Regulation mechanism of MHC II expression in TME is depicted in Fig. 3. Transcriptional regulation Class II Major Histocompatibility Complex Transactivator (CIITA) is a major transcriptional regulator of MHC II gene expression 96 . However, CIITA does not bind directly to DNA; instead, it recruits transcription factors and other co-regulatory proteins to alter chromatin interactions and the local epigenetic landscape, thereby regulating MHC II. The S-X-Y module of the MHC II promoter enables the interaction between subunits of RF-X (regulatory factors X, including RFX5, RFXB, and RFXAP in the complex) and NF-Y (nuclear factors Y, including NF-YA, NF-YB, and NF-YC in the complex), forming the MHC II enhancer. Serving as a scaffold for CIITA recruitment 97,98, the MHC II enhancer, in combination with DNA loops, promotes synergistic interactions with chromatin modifiers such as cAMP-response element binding protein (CREB)-binding protein (CBP), p300/CBP associated factor (pCAF), and steroid receptor coactivator 1 (SRC-1) 99, thereby modifying chromatin structure to from a closed to an open state. This alteration allows other DNA-binding proteins to interact with the MHC II promoter. CIITA is constitutively expressed only in professional APCs; however, its activity, and consequently MHC II expression, are regulated across all APCs 27 . For example, IFN-γ stimulates CIITA expression 76, converting monocytes from MHC II negative cells to functional APCs that express MHC II. The expression of mRNA encoding MHC II is also dependent on APC maturation. The expression of MHC II mRNA and protein is upregulated in the activated B cell state compared to the resting state. Activation of CD11c + conventional DCs (cDCs) in the spleen also increases MHC II protein synthesis; however, within 24 hours of activation, MHC II synthesis in cDCs is terminated 27 . In contrast, due to the sustained expression of CIITA 30,100 in plasmacytoid-like DCs, MHC II biosynthesis continues following activation. In addition, CIITA can bind to coactivator-associated arginine methyltransferase 1 (CARM1), resulting in arginine methylation on histone H3 arginine 17 (H3R17) and CBP, which enhances MHC II promoter interactions and MHC II gene expression 101 . CIITA also promotes cyclin-dependent kinase 7-mediated phosphorylation of RNA polymerase II, directly initiating mRNA transcription for the corresponding gene 99,102 . In addition to CIITA, other transcription factors are involved in the regulation of MHC II expression. Missense or missense mutants of interferon regulatory factor 8 (IRF8), which acts as a co-regulatory transcription factor, affect its localization to the N-terminal domain or C-terminal tail of DNA, leading to impaired promoter binding. This results in reduced expression of CD74, HLA-DM and intracellular antigen processing regulators, thereby inhibiting MHC II expression 103 . In primary diffuse large B-cell tumors, IRF8 mutations are mutually exclusive with mutations in IRF8 direct targets and major regulators of MHC II gene transcription 104-106 . Therefore, lymphomas with IRF8 mutants exhibit a higher tumor burden. Recent research found that delivering the transcription factors purine-rich nucleic acid binding protein (PU.1), IRF8 and basic leucine zipper ATF-like transcription factor 3 (BATF3) into melanoma tumor cells in mice via adenovirus vectors can reprogram these cells to function as conventional type 1 dendritic cells (cDC1). This reprogramming promotes high levels of MHC I, MHC II and the co-stimulatory molecule CD40, which, through chemokine secretion and antigen cross-presentation, remodels the TME. It recruits and expands polyclonal cytotoxic T cells, induces tumor regression, and establishes long-term systemic immune tolerance, mediating effective anticancer immunity 107 . Epigenetic modification Epigenetic modifications of MHC II molecules mainly include ubiquitination, miRNA regulation, histone deacetylation, DNA methylation, citrullination and chromatin remodeling. These modifications regulate the transcriptional activity of MHC II genes by modulating the open or closed state of chromatin. A conserved lysine residue in the MHC II β chain is ubiquitinated by the E3 ubiquitin ligase membrane-associated RING-CH-1 (MARCH1) in cells 108-111, and variations in the length of the ubiquitin chain modification affect MHC II localization. In DCs, MHC II contain longer ubiquitin chains, directing them preferentially to lysosomes. In contrast, in B cells, MHC II contain shorter ubiquitin chains that preferentially target endosomes 112 . Both pathways ultimately lead to rapid turnover of peptide-MHC II complexes, ensuring high degradation rates under steady-state conditions 31 . Notably, while ubiquitination regulates the homeostasis of MHC II, it does not appear to control changes in peptide-MHC II expression on the surface of APCs 111 . Similarly, in lung adenocarcinoma, the ubiquitin-like activating enzyme ubiquitin-like modifier activating enzyme 5 (UBA5) participates in UFMylation, a ubiquitin-like modification process, to degrade MHC proteins 113 . Database analysis shows that miR-200c-5p may target mRNA involved in MHC II protein complex binding in colorectal cancer, thereby inhibiting the viability and aggressiveness of colorectal cancer cells 114 . Histone acetylases (HATs) such as CBP/p300, can be recruited to the promoter region of MHC II gene through transcription factors or transcription co-stimulatory molecules. Then, the chromatin structure becomes more open through histone acetylation modification, thus facilitating transcription factor binding and transcriptional activation of MHC II gene. Decoy receptor 3 (DcR3), a member of the tumor necrosis factor receptor superfamily, is overexpressed in pancreatic cancer and other malignant tumors 115 . This overexpression is associated with the deacetylation of ERK / cJNK-associated histones 115-117 . The expression of MHC II-related genes in monocyte-derived macrophages (MDMs) is decreased 115,116, thereby reducing the expression of MHC II complexes. DNA methylation can inhibit MHC II expression by recruiting inhibitory proteins or preventing transcription factors from binding to DNA 118,119 . Both endogenous histone acetylation and DNA methylation lead to reduced expression of the major MHC II histocompatibility complex activator, CIITA 120 . In regulating MHC II expression, these two modifications may act in concert to ensure an appropriate immune response. For example, DNA methylation may first inhibit the expression of the MHC II, while histone acetylation may act as an activation signal to help overcome methylation-induced repression and promote MHC II gene expression in specific immune cells or during immune response activation. In addition, peptidyl arginine deiminase 4 (PAD4) citrullinates signal transducer and activator of transcription 1 (STAT1), promoting the interaction between STAT1 and protein inhibitor of activated STAT1 (PIAS1, E3 small ubiquitin-like modified ligase) in macrophages. This interaction results in dephosphorylation and dissociation of STAT1 from DNA 121,122, inhibiting its binding to the key IFN-γ response promoter region of the CIITA gene, and negatively regulating MHC II expression in macrophages 123 . Signaling pathway activation in the TME IFN-γ is the only member of type II interferon that stimulates the synthesis of MHC II on the APCs. Tumor cell lines responsive to IFN-γ induce CIITA expression via the janus kinase (JAK)/STAT signaling pathway, and certain HAT, such as CRC-1, are recruited to the MHC II promoter only following IFN-γ stimulation 124 . Among the four promoter regions of CIITA, IFN-γ primarily acts through CIITA promoter IV (CIITA-pIV). Tumor cells can diminish their response to IFN-through CIITA-pIV 125, including the reduction of transcription factor binding due to DNA hypermethylation of CpG islands around CIITA-pIV 125,126, which is associated with the aforementioned epigenetic regulation. Numerous studies have shown that changes in specific factors within the TME can activate signaling pathways or inflammatory factors to reduce the expression of MHC II complex of TAM and promote their M2 polarization, which is related to impaired tumor immune and poor prognosis. Podoplanin is a transmembrane protein that is widely expressed in both stromal cells and tumor cells 127,128 . PDPN affects macrophages by activating the Tumor Progression Locus 2 (TPL2)/ Extracellular Signal-Regulated Kinase (ERK)/CIITA pathway, downregulating MHC II expression and driving macrophages toward immunosuppressive phenotypes 129 . Additionally, elevated calcitriol levels increase cyclooxygenase-2 expression in breast cancer, resulting in higher secretion of prostaglandin E2. This, in turn, directly inhibits MHC II expression of TAM through CREB-mediated Kruppel-like factor 4 (KLF4) and promotes their M2 polarization 130 . Certain bacteria can also modulate MHC II expression by affecting the TME. For example, Akko bacterium intestinalis or its purified membrane proteins can reduce MHC II + Treg while enhancing MHC II + pDC, thereby promoting the recruitment of cytotoxic T lymphocytes to tumors 14 . Recent studies have found that exposure to Acidovorax temperans in the lung leads to a highly inflammatory state in the TME of lung cancer. In this context, mature tumor-associated neutrophils secrete colony-stimulating factor 1 (CSF1), which promotes monocyte differentiation into macrophages. These macrophages then strongly upregulate MHC II expression and stimulate T cells to polarize into Th17 polarization, thereby promoting tumor growth 131 . Metabolic regulation Metabolic reprogramming is a hallmark of cancer, enabling tumor cells to gain a growth advantage by redirecting normal metabolic pathways towards the synthesis of biomolecules 132,133 . Cancer-induced metabolic dysregulation can drive macrophages to shift from the M1 state to the M2 state, creating an environment that supports tumorigenesis 134 .M1 macrophages primarily generate energy through glycolysis, whereas M2 macrophages rely primarily on oxidative phosphorylation (OXPHOS). Tumor cells preferentially utilize the glycolytic pathway due to metabolic reprogramming in the TME, consuming large amounts of glucose and consequently lowering glucose levels in the microenvironment. In the absence of glucose, macrophages shift to utilize fatty acid oxidation and glutamine metabolism, a metabolic change that contributes to decreased MHC II expression and promotes polarization toward the M2 state 135 . Ferroptosis is an iron-dependent, lipid peroxidation-driven mode of programmed cell death, and tumor cells are often sensitized to ferroptosis by metabolic reprogramming, which reduces their sensitivity to this process and promotes rapid proliferation and survival 136,137 . Recent studies indicate that ferroptotic cells impact the early maturation of DCs, inhibiting MHC II expression and reducing their antigen cross-presentation capacity 138 . Cancer metabolic reprogramming is also directly related to fatty acid-mediated MHC II silencing; the malonyl/acetyltransferase (MAT) domain in fatty acid synthase (FASN) is a direct binding target for MHC II inducers, and FASN-catalyzed fatty acid synthesis inhibits MHC II expression 139 . The accumulation of tumor cell metabolites can likewise have an impact on APC function. For example, lactate decreases MHC II expression in DCs in cervical cancer 140 . Leucine catabolism is dependent on mitochondrial phenotypic alterations and metabolic epigenetic regulation via the acetyl coenzyme A/H3K27ac/MHC-II axis, which initiates neutrophil MHC II expression production. This, in turn, triggers direct and widespread T cell activation, antigen responsiveness, and cytotoxicity via ligand-receptor interactions 92 . Increased concentration of adenosine contributes to an immunosuppressive TME. This rise is partly due to the release of large amounts of adenosine triphosphate (ATP) from tumor cells, with adenosine being a direct hydrolysis product 141,142 . Additionally, cytokines such as hypoxia-inducible factor 1 (HIF-1) and TGF-β promote the transcription and expression of CD39 and CD73, enzymes that catalyze ATP breakdown, further increasing adenosine levels in the TME 143-146 . Adenosine activates A2aR and A2bR receptors on mature DCs, thereby increasing intracellular cAMP levels. cAMP inhibits CD86 co-stimulatory signaling expression through the Protein Kinase A (PKA)/ exchange protein directly activated by cAMP (EPAC) signaling pathway and reduces MHC II expression on DCs 147 . In addition, A2aR activation triggers cAMP/PKA/CREB signaling pathway and leads to upregulation of CREB. This indirectly reduces MHC II expression by inhibiting the production of anti-tumor cytokines, including IFN-γ, through the inhibition of nuclear factor kappa B (NF-κB) and nuclear factors that activate T cells 148 . Adenosine binds to the A2bR receptor on macrophages, inhibiting CD86 co-stimulatory signaling and MHC II expression, thereby impairing the antigen presentation capacity of macrophages 149 . Autophagy plays a crucial role in cellular metabolism and is closely related to a variety of biological processes, including energy homeostasis, stress response, and cell death. It also serves as a major survival mechanism for primary and metastatic melanoma cells 150 . α-Synuclein, as a relevant variant of melanoma cell autophagy, may depend on antigenic peptides recognized by CD4 + T cells and produced by lysosomal degradation presented on MHC II. 151 . This process significantly upregulates MHC II expression and prolonging the survival of patients with advanced melanoma 152 . 1. MHC II-related tumor immunotherapy strategies 2. Direct action on MHC II 3. Enzyme inhibitors According to the above, adenosine exerts an inhibitory effect on tumor-adapted immunity within the TME. However, adenosine has a half-life of less than 10 seconds, making direct targeting impractical. Therefore, extensive preclinical and clinical studies have explored disrupting immunosuppression by targeting adenosine-generating enzymes (CD39 and CD73) to inhibit adenosine production or blocking A2aR. In mouse models of melanoma, breast cancer, and ovarian cancer, adenosine-generating enzyme inhibitors significantly enhanced MHC II expression in DCs and macrophages, demonstrating promising antitumor effects 153-156 . In view of this, adenosine pathway inhibitors are increasingly entering clinical trials to counteract tumor-induced immunosuppression. Notably, CPI-444, an oral A2a receptor antagonist, has demonstrated antitumor efficacy in preclinical models and is currently undergoing clinical evaluation 157 . Similarly, ES002023, a monoclonal antibody targeting CD39, is in Phase 1 trials for advanced solid tumors 158 . Despite these advancements, no adenosine pathway inhibitors have received regulatory approval to date. Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9), a member of the preprotein convertase family 159, has been shown to upregulate DC infiltration and MHC II expression when inhibited, leading to effective tumor control, and enhancing the efficacy of tumor vaccines 160 . Existing studies suggest that PCSK9 may inhibit MHC II expression on tumor cells by activating the mitogen-activated protein kinase (MAPK) signaling pathway. However, further studies are needed to elucidate the underlying mechanism. JAK inhibitors, which selectively inhibit JAK activity, have been shown to significant reprogram myeloid-derived suppressor cells (MDSCs) infiltrating tumors. This reprogramming results in a dramatic decrease in the expression of various function-related markers of MDSCs and a substantial increase in MHC II expression, implying that these cells have the ability to present antigens to T cells and activate immune responses 161 . Based on the broad impact of the JAK-STAT pathway in the body, inhibiting this pathway may have potentially detrimental effects on antitumor immunity. Therefore, it is inconclusive whether the target selectivity of different JAK inhibitors affects efficacy. Targeted epigenetic regulation Epigenetic therapies can upregulate the expression of MHC II mRNA and protein expression in tumor cells, along with other components of the MHC II processing pathway. This upregulation triggers an interferon response, increasing in the presentation of neoantigens to the immune system 75,162,163 . Among the most studied epigenetic therapies are histone deacetylase inhibitors and DNA methyltransferase inhibitors targeting MHC II. Histone deacetylase inhibitors (HDACi) activate antitumor immunity in the MHC II pathway by inhibiting histone deacetylase, which preserves the lysine acetylation in histones 164 . Four HDACi have been approved by the Food and Drug Administration (FDA) for the treatment of lymphoma and MM 8,10-12 . Significant progress has also been made in the study of HDACi for the treatment of solid tumors. For example, sodium valproate/valproic acid (VPA) partially restored MHC II expression in DcR3 transgenic mice following subcutaneous inoculation with mouse colon adenocarcinoma cells, effectively circumventing the enhancement of tumor growth 165,166 . The clinical significance of VPA, both as a single agent and in combination with anticancer therapeutic agents, has been well established 8 . In mouse colon adenocarcinoma cells, IFN-γ induces transcription at the CIITA- pIV locus, whereas Trichostatin A treatment induces transcription at the CIITA-pIII locus 12 . Therefore, combination of the histone deacetylase inhibitor, TSA, with IFN-γ further increases CIITA induction. Additionally, the HDACi depressive peptide (Dep) in combination with the standard chemotherapy agent 5-fluorouracil (5-FU) enhances the anti-colorectal cancer efficacy 9 .The QAPHA molecule ((E)-3-(5-((2-cyanoquinolin-4-yl)(methyl)amino)-2-methoxyphenyl)-N-hydroxyacrylamide) , which functions as both an HDACi and a microtubule protein polymerization agent, was able to upregulate immunogenic cell death (ICD) and MHC II expression in lung cancer cells 167 . DNA methyltransferase inhibitors (DNMTi) block the function of DNMT, inhibit its degradation, and activate the expression of MHC II. At present, azacytidine and decitabine have been approved by FDA for the treatment of myelodysplastic syndrome 13 . Enhancer of Zeste Homolog 2 (EZH2), a histone methyltransferase, binds to the CIITA site and catalyzes histone trimethylation of the histone H3 lysine 27 (H3K27me3), inhibiting chromatin opening on the IFN-γ-inducing CIITA-pIV and suppressing MHC II expression 168,169 . The EZH2 inhibitor tazerestat, combined with IFN-γ therapy, can restore MHC presentation and has been clinically used to treat acute myeloid leukemia (AML) 170 . Epigenetic drugs are tailored to patient-specific molecular phenotypes and target epigenetic ”readers”, ”writers” and ”erasers” 171-173 . While these drugs offer a range of selection targets, they may also affect the expression of non-target genes caused by off-target, potentially resulting in immunosuppression, abnormal cell proliferation, and hematological side effects. Therefore, it is still necessary to further optimize the treatment regimen to improve the efficacy and minimize toxicity. Targeted metabolic regulation The modulation of amino acid metabolism in cancer immunotherapy has emerged as a prominent research focus. Since leucine treatment stimulates the HLA-DR program, enhances mitochondrial respiration, increases acetyl coenzyme A production, and epigenetically activates antigen-presenting genes, dietary leucine supplementation or targeted delivery strategies could enhance cancer immunotherapy and serve as a potential neutrophil-based therapeutic approach 92 . The discovery that tryptophan metabolites 5-hydroxytryptamine (5-HT) and 3-Hydroxyisobutyryl-CoA (3-HA) act as free radical-scavenging antioxidants to eliminate lipid peroxidation and inhibit ferroptosis via a non-classical pathway 174 is expected to attenuate the early inhibition of MHC II expression in DCs, offering potential as a novel cancer therapeutic tool. In addition, radiation tumor cell-derived microparticles (RMPs) can activate the cGAS-STING pathway 175, leading to ferroptosis. When the ferroptosis inducer RSL-3 is loaded onto RMPs (RC@RMPs), it synergistically enhances ferroptosis by promoting reactive oxygen species production, lipid peroxides, and mitochondrial destabilization. This process elevates DC MHC II expression 176 . However, the ability of ferroptosis tumor cells to inhibit the cross-presentation of soluble antigens to DCs implies that, while ferroptosis may promote DC maturation, it may also simultaneously reduce the antigen-presenting capacity of DCs, thereby impairing T cell activation and anti-tumor immune responses 138 . That is, the effect of ferroptosis on MHC II expression in DCs is complex, as it may either promote DC maturation or suppress the immune response by impairing antigen presentation. Therefore, in developing ferroptosis- based immunotherapeutic strategies, careful consideration needs to be given to improve the specificity of ferroptosis-inducing agents, tightly controlling the dosages, and modulating the key factors that influence the sensitivity of cancer cells to ferroptosis. This approach aims to harness the ferroptosis mechanism effectively while minimize toxicity for cancer treatment. Dietary changes can significantly affect the metabolite composition of the body, which in turn impacts the metabolic microenvironment of cancer cells to interfere with tumor immunity. For example, oral administration of MH (Manuka honey) can alter anti-tumor immunity by modifying gut microbiome-derived metabolites, such as indole-3-acetic acid 15 . IFN-dependent pathways enhance MHC II expression on macrophages, MHC I expression on tumor cells, and effector T cell infiltration into TME, thereby enhancing tumor immunogenicity 177 . However, the full mechanism underlying these effects remain to be explored. Activation of T cells based on MHC II expression Tumor vaccine Tumor vaccines, a form of active immunotherapy designed to strengthen suppressed or defective immune system, can overcome the early limitations of conventional treatments. They generate a systemic, targeted, and well-tolerated anti-tumor response. By activating the immune system, tumor vaccines can counteract tumor immune evasion 178,179 and represent one of the most innovative and promising strategies in cancer treatment. Neoantigens, generated from non-synonymous somatic mutations, alternative RNA splicing, or post-translational modification disorders during tumorigenesis, serve as tumor-specific immune targets for personalized cancer vaccines 180,181 . Numerous preclinical and clinical studies have shown that neoantigen-targeted vaccines can activate neoantigen-specific T cells, enabling them to recognize and eliminate tumor cells expressing these neoantigens 182-185 (Table 3). Clinical trials have demonstrated that the isocitrate dehydrogenase 1 (IDH1)-specific peptide vaccine for glioma induces a robust anti-tumor immune response with MHC II restriction mutations. The reactive Th cells can re-stimulate cytotoxic T cells, effectively targeting and combating IDH1 + glioma 6,7 . CD4 + T cells help activate CD8 + T cells by secreting cytokines such as IFN-γ and IL-2 186 . In case of abnormal expression of MHC II molecules in tumor cells and insufficient CD4 + T cell assistance, CD8 + T cells in the TME are more prone to exhaustion or tolerance, with exhausted T cells exhibiting high levels of inhibitory receptor expression. Consequently, a balanced response from both CD4 + T cell and CD8 + T cell is essential for effective anti-tumor immunity 187 . Multi-epitope vaccines can simultaneously target multiple tumor mutations, making them suitable for addressing antigen escape and clonal heterogeneity. Therefore, epitopes of neoantigen vaccine should contain both MHC I and MHC II binding peptides 188 . Vaccines containing neoepitopes designed for CT26 colorectal cancer can simultaneously bind MHC I, MHC II, and TCR, inducing IFN-γ production 189 . Multi-epitope prostate specific antigen (PSA) D15 and Cag Pathogenicity Island Gene 11 (Cag11) antigens for H. pylori infection and gastric cancer prevention can also interface with multiple immune receptors such as B cells, MHC I, MHC II and TLR-2/4 190 . Notably, the effectiveness of therapeutic tumor-specific neoantigen long peptide vaccines is highly dependent on the dose of MHC II tumor neoantigens contained. Excessive loading of tsMHC II neoepitopes in the vaccines can lead to the production of CD4 + type 1 regulatory T cell (Tr1) cells with immunosuppressive activity, completely reversing the efficacy of the vaccines 191 . Interestingly, the expression of MHC II in small intestinal epithelial cells is also positively correlated with Tr1 cells. In the proximal small intestine, food-induced Gasdermin D protein forms an N13 fragment that enhance STAT1-mediated transcriptional regulation of CIITA, leading to increase the expression of MHC II in intestinal epithelial cells (IEC) and the subsequent upregulation of Tr1 cells 192 . Although this study was conducted in the context of food tolerance, the findings suggest that the mechanism by which MHC II upregulation induces immunosuppressive Tr1 cell production could serve as a novel target for intestinal cancer immunotherapy. DCs can participate in both MHC I and MHC II antigen cross-presentation process 193 and can cross the blood-brain barrier, making them promising tools for cancer immunotherapy 194 . DC vaccines have shown promising outcomes in preclinical trials 195 and are currently being evaluated in clinical trials 194 . The therapeutic efficacy of DC vaccines may be limited by several factors, such as their inability to activate specific cytotoxic T lymphocytes or NK cells, as well as their failure to overcome the immunosuppressive effects of Tregs or MDSCs 196 . With the development of technology, it is now possible to design DNA and RNA vaccines based on tumor-associated antigen immune epitopes. These vaccines can encode both tumor-associated antigen immune epitopes ”checkpoint” molecules within a single plasmid, enabling the generation of transgenic DCs 197,198 . This approach significantly enhances the induction of cytotoxic immune response. In addition, DC-derived exosomes are promising candidates for cancer immunotherapy due to their ability to stimulate the immune response in vivo . Tumor peptide-pulsed exosomes, which carry MHC II, adhesion and co-stimulatory molecules, have been developed as cell-free vaccines to eliminate tumors. These exosomes have shown positive results in preclinical trials, confirming their ability to enhance the ability of immune system to recognize and attack tumors 199 . According to recent research, the application of viral vaccines to enhance the expression of MHC II is gradually advancing. PeptiCab, a vaccine derived from AdCab (an oncolytic adenovirus) coated with MHC I-restricted tumor peptides, polarizes neutrophils by upregulating MHC II, CD80, and CD86, enabling them to obtain an antigen-presenting phenotype and enhancing T cell expansion 200 . Transcriptome data showed that a mutant of the coliform heat-unstable toxin B subunit (LTB), LTB26, enhances immune response by upregulating BCR and MHC II related pathways 201 . Additionally, the development of cancers such as gastric cancer, nasopharyngeal cancer, and liver cancer has been closely related to bacterial or viral infections. The use of pathogen mutants as vaccine adjuvants offers a promising strategy for preventing the occurrence of this type of cancer. Tumor vaccines designed for MHC II gene expression are an important research direction in the field of cancer immunotherapy. In a recent study, a vaccine was developed using a combination of epigenetic drugs HDAC and DNMT inhibitors to enhance MHC II expression in pancreatic cancer-1 cells. Consequently, this vaccine demonstrated improved lymphocyte proliferation, increased anti-tumor activity of CD8 + T cells, and elevated secretion of IFN-γ and IL-2 by Th1 lymphocytes. It also reduces the secretion of TGF-β and IL-4 by Th2 lymphocytes 202, making it a promising candidate for pancreatic cancer. Since CIITA-driven tumor cells expressing MHC II can act as an APC substitute for their own tumor antigens, immunization with CIITA-modified OSCC tumor cells has been shown to strongly inhibit tumor growth and, more importantly, to induce anti-tumor immune memory capable of resisting subsequent attacks by parental microrchidia CW-type zinc 2 (MORC2) tumor cells 203 . At present, the limitation about low immunogenicity of tumor vaccines still exists. Researchers have addressed this limitation by developing innovative strategies such as outer membrane vesicles (rOMV), advanced antigen delivery systems, and adjuvants, including bioassembled biopolymer particles (BPs) 189,204 and DX with L-arginine (ArgDX) nanogel adjuvant carriers 205 . The optimal vaccine in terms of solubility, stability, immunogenicity and non-allergenicity has been confirmed through structural analysis at the model level. However, in vivo immunological experiments are still needed to confirm the effectiveness of the vaccine. ICBs Anti-tumor CD4 + Th cells are conducive to MHC II restriction of tumor antigen recognition. However, their functional activity can be blocked through programmed cell death protein 1(PD-1)/PD-L1 interaction 206 . Tumor cells with adaptive resistance to PD-1 often exhibition high levels of MHC II expression 73 . Inhibitory ligands of MHC II expressed on activated T cells, such as lymphocyte activation gene 3 (LAG-3), MHC II Fc receptor-like 6 (FCRL6), T cell immunoglobulin mucin 3 (TIM3), have emerged as promising immunotherapy targets 207-211 . Antibody or fusion protein therapies targeting these immune checkpoints can be combined with existing PD-1/PD-L1 immune checkpoint inhibitors, demonstrating promising therapeutic potential. Recent studies have shown that LAG-3 cis-dimerization and glycosylation are critical for its stability and binding to MHC II and fibrinogen-like protein 1 (FGL1) ligands 212 . Intensive exploration of the structural domains of these immune checkpoint-binding antibodies provides a structural basis for the development of antibodies targeting immune checkpoints and is expected to expand the clinical applications of these biochemical pathways. There are several potential targets that have yet to be applied clinically, but these findings provide a solid theoretical basis for developing new ICB therapies. For example, inhibition of targets such as CD276 213 and polo-like kinase 1 (PLK1) 214 has been shown to enhanced MHC II expression in TAM. Additionally, granular β-1,3-glucan (GPG) extracted from Ganoderma lucidum spore wall can inhibit the MDSC differentiation through the Dectin-1 pathway, reducing PD-L1 and indoleamine-2,3-dioxygenase 1 (IDO1) expression on MDSCs while promoting MHC II, CD86, tumor necrosis factor α(TNF-α) and IL-6 expression 215. Other immunotherapies Tumor immune gene therapy aims to enhance the anti-tumor immune response by introducing immune genes or antigens 216 . The provision of immune stimulants can address some limitations of immune gene therapy. For instance, the MLSV system, which is assembled by nanomaterials and tumor cell lysates, has been reported to boost immune response by increasing DCs maturation rate and MHC II expression 217 . Some novel photosensitizers of photodynamic therapy (PDT) can not only increase the production of reactive oxygen species (ROS) in tumor cells, but also induce ICD, thereby exposing damage associated molecular patterns (DAMPs) and modulating immune responses in the TME. The in-situ nano-vaccine prepared by anchoring ultra-small γ-MnO2 nanodots on Ti 3 C 2 (OH) 2 and modified by bovine serum albumin (BSA) is an excellent photosensitizer and ICD inducer under near-infrared irradiation. It significantly increases MHC II + DC and triggers specific anti-tumor immune response in cold tumor models 218 . The nanoparticle ISDN, prepared by self-assembly of clinical drug indocyanine green (ICG) and 17-DMAG (HSP90 inhibitor), significantly increases cytotoxic T lymphocyte (CTL) tumor invasion, increase the contents of MHC I and MHC II in TME, and induces a strong systemic immune response against pancreatic cancer 219 . Similarly, photostimulated nanocarriers SLN-AIPc have been shown to elevate MHC II, CD80 and CD86 expression in melanoma following PDT treatment, promote produce IL-12 and IFN-γ, and activate the anti-tumor effect 220 . Summary and Prospects In the cancer context, MHC II is widely expressed on both professional and atypical APCs, making it an attractive tumor marker in cancer immunology research and clinical practice. TsMHC II expression, on the one hand, is associated with improved responses to immune checkpoint inhibitors 57,73,221-224, which facilitates better selection of patients who are more likely to benefit from tumor immunotherapy. Numerous studies have shown that MHC II expression on tumor-infiltrating lymphocytes can be used as a marker to predict the efficacy of ICB therapy 73,223,225-228 . However, the predictive accuracy of this single indicator remains suboptimal. Future studies focusing on combination markers, including MHC II, holds promise for improving the prediction of ICB therapy outcomes and addressing this clinical challenge 229-231 . Elevated expression of MHC II-related genes has been observed in patients with tumor-reactive CD8 + T cell activation in colorectal cancer 232, lung cancer 233, breast cancer 234, and head and neck squamous cell carcinoma 235,236, although mainly in non-blood tissue types and with different signature genes. Future studies with larger cohorts and protein-level validation are expected to strengthen the predictive power of MHC II-related features. On the other hand, MHC II expression can also help characterize different subtypes within the same cancer type, offering valuable guidance for prognostic assessment and treatment strategy selection. For instance, in NSCLC, patients negative for HRD exhibited significant activation of MHC II, IFN-γ, and effector memory CD8 + T cells, correlating with better outcomes. Conversely, HRD-positive patients demonstrate opposite characteristics and poor prognosis, along with unsatisfied response to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) and immunotherapy 64 . The inflammatory phenotype (SCCC-I) of small cell cervical cancer (SCCC) exhibits higher MHC II complex expression compared to the other two neuroendocrine subtypes. Patients with SCCC-I have a higher survival rate and are more likely to benefit from ICB treatment 237 . The primary objective of cancer immunotherapies targeting MHC II is to amplify the anti-tumor immune response by activating immune active cells. The interaction between MHC II and peptides determines the specificity of the immune response, making the prediction of MHC II-peptide interactions crucial for identifying highly immunogenicity tumor neoantigens. However, this prediction is challenging due to the several factors. At first, the MHC II gene exhibits high polymorphism 238, which results from the presence of multiple alleles at each locus. Additionally, the diversity of the peptide flanking sequence, variability in binding cores 239,240, and the availability of immunogenic epitopes further complicate accurate prediction. At present, competitive binding assay 241, enzyme-linked immunospot (ELISPOT) assay 242 and mass spectrometry 243-245 are mainly used to evaluate the interaction of MHC by quantifying the binding affinity and/or immunogenicity of MHC binding peptides 246-249 . High-throughput experiments have also been developed to identify accurate MHC-peptide interactions at the peptide set or genome level 244,250 . However, the high cost and time-consuming nature of these existing experimental techniques have limited their application for large-scale prediction 251 . To solve the above problems, many researchers have focused on developing comprehensive databases of MHC epitopes 252 . Tools like MixMHC2pred enable the identification of MHC II motifs for any MHC II allele using the amino acid sequences of the α and β chain 253 . It provides experimental data on MHC binding for each epitope, along with detailed information on HLA allelic specificity, inferred minimum epitope sequences, and the allelic limitations of known epitopes. It serves as a valuable resource for identifying promising immunotherapy targets and advancing the design of antigen-specific cancer immunotherapies. However, the current version of the database includes epitopes that may not trigger T cell responses, and the immunogenicity scores of MHC epitopes require further validating through T cell assay. Moving forward, such database needs to be continuously updated and include more data on the outcome of T cell activation to better support the development of cancer immunotherapy. In addition, the ability of T cells to recognize specific MHC-peptide complexes through their TCR and induce various effects is an extremely important link in activating the anti-tumor immune response 254 . Accurate identification of epitope-containing TCRs is essential for advancing our understanding of tumor prevention and treatment. Determining the specific antigens recognized by TCRs is crucial for successful tumor vaccines, adenosineptive T cell therapy and other immunotherapies. However, due to the complexity of MHC II 255, it is important to understand the specific antigens recognized by TCRs. At present, antigen discovery technologies are mainly focused on MHC I-restricted TCRs, while equivalent methods for detecting MHC II-restricted CD4 + T cells or evaluating TCR reactivity have not advanced at the same pace. To date, most TCR-like antibodies have been generated using phage display libraries 256 . However, due to the inherent complexity of this recognition mechanism, experimental detection and verification of TCR-epitopes interactions is often time-consuming and costly 257 . Furthermore, it is essential to ensure that TCR-like antibodies cannot independently recognize MHC II molecules. Researchers have developed innovative approaches to address the challenges of the TCR-epitope interaction mapping. These include the use of synthetic cell circuits for high-throughput identification of MHC I- and MHC II-restricted TCRs 258, the graph learning framework GTE 259 to predict the binding specificity of TCR-epitope, and computational simulations of various motifs 260-265 . Additionally, methods such as encoding MHC II that present covalently bound peptides using signal transduction and antigen-presenting bifocal receptor platforms (SABR-II) 266 are gradually addressing this challenge. Advancements in these technologies will accelerate the discovery of T cell antigens in cancer and enable a systematic characterization of T cell response profiles, ultimately reducing the risks associated with therapeutic TCR development. In summary, the widespread expression of MHC II in cancer-associated cells positions it as a pivotal driver of innovation in cancer therapy. As our understanding of the role of MHC II in the TME deepens, future advancements may include the development of MHC II-peptide complex-based personalized vaccines, optimized applications of ICBs, combined immunotherapy strategies and biomarker-guided precision medicine. These approaches hold the potential to provide cancer patients with more effective therapeutic options, improve the survival rates and enhance the quality of life.

Jiaqi Liu and Xueru Song contributed equally to this work. This work was supported by grants from the National Natural Science Foundation of China (82403681), the Jiangsu Funding Program for Excellent Postdoctoral Talent (2023ZB381) and the Science Foundation of the Jiangsu Province, China (BK20241677). Conflict of Interest Statement The authors declare no conflicts of interest. Author contributions J.L. X.S. and W.G.: Conceptualization, Visualization, Writing—original draft, Writing—review & editing. W.L. and S.X.: Visualization. X.C. and Z.L.: Conceptualization, Supervision, Writing—review & editing. All authors read and approved the final manuscript.

1. Kraehenbuehl L, Weng CH, Eghbali S, Wolchok JD, Merghoub T Nat Rev Clin Oncol. 2022;19(1):37-50. 2. Lerner EC, Woroniecka KI, D’Anniballe VM, Wilkinson DS, Mohan AA, Lorrey SJ, Waibl-Polania J, Wachsmuth LP, Miggelbrink AM, Jackson JD, Cui X, Raj JA, Tomaszewski WH, Cook SL, Sampson JH, Patel AP, Khasraw M, Gunn MD, Fecci PE Nat Cancer. 2023;4(9):1258-1272. 3. You S, Li S, Zeng L, Song J, Li Z, Li W, Ni H, Xiao X, Deng W, Li H, Lin W, Liang C, Zheng Y, Cheng SC, Xiao N, Tong M, Yu R, Huang J, Huang H, Xu H, Han J, Ren J, Mao K Cancer Cell. 2024;42(8):1415-1433.e1412. 4. Alspach E, Lussier DM, Miceli AP, Kizhvatov I, DuPage M, Luoma AM, Meng W, Lichti CF, Esaulova E, Vomund AN, Runci D, Ward JP, Gubin MM, Medrano RFV, Arthur CD, White JM, Sheehan KCF, Chen A, Wucherpfennig KW, Jacks T, Unanue ER, Artyomov MN, Schreiber RD Nature. 2019;574(7780):696-701. 5. Kravtsov DS, Erbe AK, Sondel PM, Rakhmilevich AL Front Immunol. 2022;13:972021. 6. Platten M, Bunse L, Wick A, Bunse T, Le Cornet L, Harting I, Sahm F, Sanghvi K, Tan CL, Poschke I, Green E, Justesen S, Behrens GA, Breckwoldt MO, Freitag A, Rother LM, Schmitt A, Schnell O, Hense J, Misch M, Krex D, Stevanovic S, Tabatabai G, Steinbach JP, Bendszus M, von Deimling A, Schmitt M, Wick W Nature. 2021;592(7854):463-468. 7. Schumacher T, Bunse L, Pusch S, Sahm F, Wiestler B, Quandt J, Menn O, Osswald M, Oezen I, Ott M, Keil M, Balß J, Rauschenbach K, Grabowska AK, Vogler I, Diekmann J, Trautwein N, Eichmüller SB, Okun J, Stevanović S, Riemer AB, Sahin U, Friese MA, Beckhove P, von Deimling A, Wick W, Platten M Nature. 2014;512(7514):324-327. 8. Magner WJ, Kazim AL, Stewart C, Romano MA, Catalano G, Grande C, Keiser N, Santaniello F, Tomasi TB J Immunol. 2000;165(12):7017-7024. 9. Okada K, Hakata S, Terashima J, Gamou T, Habano W, Ozawa S Oncol Rep. 2016;36(4):1875-1885. 10. Cycon KA, Mulvaney K, Rimsza LM, Persky D, Murphy SP Immunology. 2013;140(2):259-272. 11. Höring E, Podlech O, Silkenstedt B, Rota IA, Adamopoulou E, Naumann U Anticancer Res. 2013;33(4):1351-1360. 12. Chou SD, Khan AN, Magner WJ, Tomasi TB Int Immunol. 2005;17(11):1483-1494. 13. Li H, Chiappinelli KB, Guzzetta AA, Easwaran H, Yen RW, Vatapalli R, Topper MJ, Luo J, Connolly RM, Azad NS, Stearns V, Pardoll DM, Davidson N, Jones PA, Slamon DJ, Baylin SB, Zahnow CA, Ahuja N Oncotarget. 2014;5(3):587-598. 14. Zhu Z, Huang J, Zhang Y, Hou W, Chen F, Mo YY, Zhang Z Cell Rep. 2024;43(6):114306. 15. Tintelnot J, Xu Y, Lesker TR, Schönlein M, Konczalla L, Giannou AD, Pelczar P, Kylies D, Puelles VG, Bielecka AA, Peschka M, Cortesi F, Riecken K, Jung M, Amend L, Bröring TS, Trajkovic-Arsic M, Siveke JT, Renné T, Zhang D, Boeck S, Strowig T, Uzunoglu FG, Güngör C, Stein A, Izbicki JR, Bokemeyer C, Sinn M, Kimmelman AC, Huber S, Gagliani N Nature. 2023;615(7950):168-174. 16. Axelrod ML, Cook RS, Johnson DB, Balko JM Clin Cancer Res. 2019;25(8):2392-2402. 17. Karp DR, Teletski CL, Jaraquemada D, Maloy WL, Coligan JE, Long EO J Exp Med. 1990;171(3):615-628. 18. Lotteau V, Teyton L, Burroughs D, Charron D Nature. 1987;329(6137):339-341. 19. Jenkins MK, Schwartz RH J Exp Med. 1987;165(2):302-319. 20. Alcover A, Alarcón B, Di Bartolo V Annu Rev Immunol. 2018;36:103-125. 21. Barker DJ, Maccari G, Georgiou X, Cooper MA, Flicek P, Robinson J, Marsh SGE Nucleic Acids Res. 2023;51(D1):D1053-d1060. 22. van Lith M, McEwen-Smith RM, Benham AM J Biol Chem. 2010;285(52):40800-40808. 23. Lim JP, Gleeson PA Immunol Cell Biol. 2011;89(8):836-843. 24. Kleijmeer MJ, Ossevoort MA, van Veen CJ, van Hellemond JJ, Neefjes JJ, Kast WM, Melief CJ, Geuze HJ J Immunol. 1995;154(11):5715-5724. 25. Jiang HR, Muckersie E, Robertson M, Xu H, Liversidge J, Forrester JV J Leukoc Biol. 2002;72(5):978-985. 26. Collin M, Bigley V Immunology. 2018;154(1):3-20. 27. Wilson NS, El-Sukkari D, Villadangos JA Blood. 2004;103(6):2187-2195. 28. Pierre P, Turley SJ, Gatti E, Hull M, Meltzer J, Mirza A, Inaba K, Steinman RM, Mellman I Nature. 1997;388(6644):787-792. 29. ten Broeke T, van Niel G, Wauben MH, Wubbolts R, Stoorvogel W Traffic. 2011;12(8):1025-1036. 30. Young LJ, Wilson NS, Schnorrer P, Proietto A, ten Broeke T, Matsuki Y, Mount AM, Belz GT, O’Keeffe M, Ohmura-Hoshino M, Ishido S, Stoorvogel W, Heath WR, Shortman K, Villadangos JA Nat Immunol. 2008;9(11):1244-1252. 31. Cella M, Engering A, Pinet V, Pieters J, Lanzavecchia A Nature. 1997;388(6644):782-787. 32. Kleijmeer M, Ramm G, Schuurhuis D, Griffith J, Rescigno M, Ricciardi-Castagnoli P, Rudensky AY, Ossendorp F, Melief CJ, Stoorvogel W, Geuze HJ J Cell Biol. 2001;155(1):53-63. 33. Chow A, Toomre D, Garrett W, Mellman I Nature. 2002;418(6901):988-994. 34. Boes M, Cerny J, Massol R, Op den Brouw M, Kirchhausen T, Chen J, Ploegh HL Nature. 2002;418(6901):983-988. 35. Nesbeth Y, Scarlett U, Cubillos-Ruiz J, Martinez D, Engle X, Turk MJ, Conejo-Garcia JR Cancer Res. 2009;69(15):6331-6338. 36. Tesone AJ, Rutkowski MR, Brencicova E, Svoronos N, Perales-Puchalt A, Stephen TL, Allegrezza MJ, Payne KK, Nguyen JM, Wickramasinghe J, Tchou J, Borowsky ME, Rabinovich GA, Kossenkov AV, Conejo-Garcia JR Cell Rep. 2016;14(7):1774-1786. 37. Cassetta L, Fragkogianni S, Sims AH, Swierczak A, Forrester LM, Zhang H, Soong DYH, Cotechini T, Anur P, Lin EY, Fidanza A, Lopez-Yrigoyen M, Millar MR, Urman A, Ai Z, Spellman PT, Hwang ES, Dixon JM, Wiechmann L, Coussens LM, Smith HO, Pollard JW Cancer Cell. 2019;35(4):588-602.e510. 38. Christofides A, Strauss L, Yeo A, Cao C, Charest A, Boussiotis VA Nat Immunol. 2022;23(8):1148-1156. 39. Umemura N, Saio M, Suwa T, Kitoh Y, Bai J, Nonaka K, Ouyang GF, Okada M, Balazs M, Adany R, Shibata T, Takami T J Leukoc Biol. 2008;83(5):1136-1144. 40. Mills CD, Kincaid K, Alt JM, Heilman MJ, Hill AM J Immunol. 2000;164(12):6166-6173. 41. Chávez-Galán L, Olleros ML, Vesin D, Garcia I Front Immunol. 2015;6:263. 42. Kodumudi KN, Woan K, Gilvary DL, Sahakian E, Wei S, Djeu JY Clin Cancer Res. 2010;16(18):4583-4594. 43. Chaudagar K, Hieromnimon HM, Khurana R, Labadie B, Hirz T, Mei S, Hasan R, Shafran J, Kelley A, Apostolov E, Al-Eryani G, Harvey K, Rameshbabu S, Loyd M, Bynoe K, Drovetsky C, Solanki A, Markiewicz E, Zamora M, Fan X, Schürer S, Swarbrick A, Sykes DB, Patnaik A Clin Cancer Res. 2023;29(10):1952-1968. 44. Zavidij O, Haradhvala NJ, Mouhieddine TH, Sklavenitis-Pistofidis R, Cai S, Reidy M, Rahmat M, Flaifel A, Ferland B, Su NK, Agius MP, Park J, Manier S, Bustoros M, Huynh D, Capelletti M, Berrios B, Liu CJ, He MX, Braggio E, Fonseca R, Maruvka YE, Guerriero JL, Goldman M, Van Allen EM, McCarroll SA, Azzi J, Getz G, Ghobrial IM Nat Cancer. 2020;1(5):493-506. 45. Lankar D, Vincent-Schneider H, Briken V, Yokozeki T, Raposo G, Bonnerot C J Exp Med. 2002;195(4):461-472. 46. Yuseff MI, Reversat A, Lankar D, Diaz J, Fanget I, Pierobon P, Randrian V, Larochette N, Vascotto F, Desdouets C, Jauffred B, Bellaiche Y, Gasman S, Darchen F, Desnos C, Lennon-Duménil AM Immunity. 2011;35(3):361-374. 47. Siemasko K, Eisfelder BJ, Williamson E, Kabak S, Clark MR J Immunol. 1998;160(11):5203-5208. 48. Groen-van Schooten TS, Franco Fernandez R, van Grieken NCT, Bos EN, Seidel J, Saris J, Martínez-Ciarpaglini C, Fleitas TC, Thommen DS, de Gruijl TD, Grootjans J, Derks S J Immunother Cancer. 2024;12(7). 49. Guy TV, Terry AM, McGuire HM, Shklovskaya E, Fazekas de St Groth B Oncoimmunology. 2024;13(1):2290799. 50. Jensen PE Nat Immunol. 2007;8(10):1041-1048. 51. Rodríguez JA Oncol Lett. 2017;14(4):4415-4427. 52. Bradley SD, Chen Z, Melendez B, Talukder A, Khalili JS, Rodriguez-Cruz T, Liu S, Whittington M, Deng W, Li F, Bernatchez C, Radvanyi LG, Davies MA, Hwu P, Lizée G Cancer Immunol Res. 2015;3(6):602-609. 53. Wang Y, Wang X, Cui X, Zhuo Y, Li H, Ha C, Xin L, Ren Y, Zhang W, Sun X, Ge L, Liu X, He J, Zhang T, Zhang K, Yao Z, Yang X, Yang J Sci Adv. 2020;6(22). 54. Concha A, Ruiz-Cabello F, Cabrera T, Nogales F, Collado A, Garrido F Eur J Immunogenet. 1995;22(4):299-310. 55. Oldford SA, Robb JD, Codner D, Gadag V, Watson PH, Drover S Int Immunol. 2006;18(11):1591-1602. 56. Oldford SA, Robb JD, Watson PH, Drover S Int J Cancer. 2004;112(3):399-406. 57. Forero A, Li Y, Chen D, Grizzle WE, Updike KL, Merz ND, Downs-Kelly E, Burwell TC, Vaklavas C, Buchsbaum DJ, Myers RM, LoBuglio AF, Varley KE Cancer Immunol Res. 2016;4(5):390-399. 58. Walsh MD, Dent OF, Young JP, Wright CM, Barker MA, Leggett BA, Bokey L, Chapuis PH, Jass JR, Macdonald GA Int J Cancer. 2009;125(5):1231-1237. 59. Griffith BD, Turcotte S, Lazarus J, Lima F, Bell S, Delrosario L, McGue J, Krishnan S, Oneka MD, Nathan H, Smith JJ, D’Angelica MI, Shia J, Di Magliano MP, Rao A, Frankel TL Cancers (Basel). 2022;14(17). 60. Almeida-Nunes DL, Nunes M, Osório H, Ferreira V, Lobo C, Monteiro P, Abreu MH, Bartosch C, Silvestre R, Dinis-Oliveira RJ, Ricardo S Biochem Biophys Rep. 2024;39:101755. 61. Rocconi RP, Stanbery L, Madeira da Silva L, Barrington RA, Aaron P, Manning L, Horvath S, Wallraven G, Bognar E, Walter A, Nemunaitis J Vaccines (Basel). 2021;9(8). 62. Burdett NL, Willis MO, Pandey A, Twomey L, Alaei S, Bowtell DDL, Christie EL Nat Commun. 2024;15(1):6069. 63. Ding G, Zhou L, Shen T, Cao L Oncol Lett. 2018;15(3):3760-3765. 64. Wang Y, Ma Y, He L, Du J, Li X, Jiao P, Wu X, Xu X, Zhou W, Yang L, Di J, Zhu C, Xu L, Sun T, Li L, Liu D, Wang Z Chin J Cancer Res. 2024;36(3):282-297. 65. Hu J, Zhang L, Xia H, Yan Y, Zhu X, Sun F, Sun L, Li S, Li D, Wang J, Han Y, Zhang J, Bian D, Yu H, Chen Y, Fan P, Ma Q, Jiang G, Wang C, Zhang P Genome Med. 2023;15(1):14. 66. Johnson AM, Boland JM, Wrobel J, Klezcko EK, Weiser-Evans M, Hopp K, Heasley L, Clambey ET, Jordan K, Nemenoff RA, Schenk EL J Thorac Oncol. 2021;16(10):1694-1704. 67. Taylor JG, Truelove E, Clear A, Calaminici M, Gribben JG Haematologica. 2023;108(4):1068-1082. 68. Nagasaki J, Togashi Y, Sugawara T, Itami M, Yamauchi N, Yuda J, Sugano M, Ohara Y, Minami Y, Nakamae H, Hino M, Takeuchi M, Nishikawa H Blood Adv. 2020;4(17):4069-4082. 69. Larkin RM, Lopez DC, Robbins YL, Lassoued W, Canubas K, Warner A, Karim B, Vulikh K, Hodge JW, Floudas CS, Gulley JL, Gallia GL, Allen CT, London NR, Jr. J Transl Med. 2024;22(1):524. 70. Armstrong TD, Clements VK, Martin BK, Ting JP, Ostrand-Rosenberg S Proc Natl Acad Sci U S A. 1997;94(13):6886-6891. 71. Yan S, Zhang X, Lin Q, Du M, Li Y, He S, Chen J, Li X, Bei J, Chen S, Song M Cancer Immunol Immunother. 2024;73(10):206. 72. Zheng L, Qin S, Si W, Wang A, Xing B, Gao R, Ren X, Wang L, Wu X, Zhang J, Wu N, Zhang N, Zheng H, Ouyang H, Chen K, Bu Z, Hu X, Ji J, Zhang Z Science. 2021;374(6574):abe6474. 73. Johnson DB, Estrada MV, Salgado R, Sanchez V, Doxie DB, Opalenik SR, Vilgelm AE, Feld E, Johnson AS, Greenplate AR, Sanders ME, Lovly CM, Frederick DT, Kelley MC, Richmond A, Irish JM, Shyr Y, Sullivan RJ, Puzanov I, Sosman JA, Balko JM Nat Commun. 2016;7:10582. 74. Callahan MJ, Nagymanyoki Z, Bonome T, Johnson ME, Litkouhi B, Sullivan EH, Hirsch MS, Matulonis UA, Liu J, Birrer MJ, Berkowitz RS, Mok SC Clin Cancer Res. 2008;14(23):7667-7673. 75. Turner TB, Meza-Perez S, Londoño A, Katre A, Peabody JE, Smith HJ, Forero A, Norian LA, Straughn JM, Jr., Buchsbaum DJ, Randall TD, Arend RC Oncotarget. 2017;8(27):44159-44170. 76. Luo Y, Xia Y, Liu D, Li X, Li H, Liu J, Zhou D, Dong Y, Li X, Qian Y, Xu C, Tao K, Li G, Pan W, Zhong Q, Liu X, Xu S, Wang Z, Liu R, Zhang W, Shan W, Fang T, Wang S, Peng Z, Jin P, Jin N, Shi S, Chen Y, Wang M, Jiao X, Luo M, Gong W, Wang Y, Yao Y, Zhao Y, Huang X, Ji X, He Z, Zhao G, Liu R, Wu M, Chen G, Hong L, Ma D, Fang Y, Liang H, Gao Q Cell. 2024. 77. Bielski CM, Zehir A, Penson AV, Donoghue MTA, Chatila W, Armenia J, Chang MT, Schram AM, Jonsson P, Bandlamudi C, Razavi P, Iyer G, Robson ME, Stadler ZK, Schultz N, Baselga J, Solit DB, Hyman DM, Berger MF, Taylor BS Nat Genet. 2018;50(8):1189-1195. 78. Gerstung M, Jolly C, Leshchiner I, Dentro SC, Gonzalez S, Rosebrock D, Mitchell TJ, Rubanova Y, Anur P, Yu K, Tarabichi M, Deshwar A, Wintersinger J, Kleinheinz K, Vázquez-García I, Haase K, Jerman L, Sengupta S, Macintyre G, Malikic S, Donmez N, Livitz DG, Cmero M, Demeulemeester J, Schumacher S, Fan Y, Yao X, Lee J, Schlesner M, Boutros PC, Bowtell DD, Zhu H, Getz G, Imielinski M, Beroukhim R, Sahinalp SC, Ji Y, Peifer M, Markowetz F, Mustonen V, Yuan K, Wang W, Morris QD, Spellman PT, Wedge DC, Van Loo P Nature. 2023;614(7948):E42. 79. Wu CH, Hsieh CS, Chang YC, Huang CC, Yeh HT, Hou MF, Chung YC, Tu SH, Chang KJ, Chattopadhyay A, Lai LC, Lu TP, Li YH, Tsai MH, Chuang EY Commun Biol. 2021;4(1):1052. 80. López S, Lim EL, Horswell S, Haase K, Huebner A, Dietzen M, Mourikis TP, Watkins TBK, Rowan A, Dewhurst SM, Birkbak NJ, Wilson GA, Van Loo P, Jamal-Hanjani M, Swanton C, McGranahan N Nat Genet. 2020;52(3):283-293. 81. Elyada E, Bolisetty M, Laise P, Flynn WF, Courtois ET, Burkhart RA, Teinor JA, Belleau P, Biffi G, Lucito MS, Sivajothi S, Armstrong TD, Engle DD, Yu KH, Hao Y, Wolfgang CL, Park Y, Preall J, Jaffee EM, Califano A, Robson P, Tuveson DA Cancer Discov. 2019;9(8):1102-1123. 82. Yang D, Liu J, Qian H, Zhuang Q Exp Mol Med. 2023;55(7):1322-1332. 83. Gerling M, Büller NV, Kirn LM, Joost S, Frings O, Englert B, Bergström Å, Kuiper RV, Blaas L, Wielenga MC, Almer S, Kühl AA, Fredlund E, van den Brink GR, Toftgård R Nat Commun. 2016;7:12321. 84. Shin K, Lim A, Zhao C, Sahoo D, Pan Y, Spiekerkoetter E, Liao JC, Beachy PA Cancer Cell. 2014;26(4):521-533. 85. Pallangyo CK, Ziegler PK, Greten FR J Exp Med. 2015;212(13):2253-2266. 86. Mizutani Y, Kobayashi H, Iida T, Asai N, Masamune A, Hara A, Esaki N, Ushida K, Mii S, Shiraki Y, Ando K, Weng L, Ishihara S, Ponik SM, Conklin MW, Haga H, Nagasaka A, Miyata T, Matsuyama M, Kobayashi T, Fujii T, Yamada S, Yamaguchi J, Wang T, Woods SL, Worthley D, Shimamura T, Fujishiro M, Hirooka Y, Enomoto A, Takahashi M Cancer Res. 2019;79(20):5367-5381. 87. Biffi G, Oni TE, Spielman B, Hao Y, Elyada E, Park Y, Preall J, Tuveson DA Cancer Discov. 2019;9(2):282-301. 88. Bonnin E, Rodrigo Riestra M, Marziali F, Mena Osuna R, Denizeau J, Maurin M, Saez JJ, Jouve M, Bonté PE, Richer W, Nevo F, Lemoine S, Girard N, Lefevre M, Borcoman E, Vincent-Salomon A, Baulande S, Moreau HD, Sedlik C, Hivroz C, Lennon-Duménil AM, Tosello Boari J, Piaggio E Nat Commun. 2024;15(1):3749. 89. Beauvillain C, Delneste Y, Scotet M, Peres A, Gascan H, Guermonprez P, Barnaba V, Jeannin P Blood. 2007;110(8):2965-2973. 90. Ashtekar AR, Saha B Trends Immunol. 2003;24(9):485-490. 91. Vono M, Lin A, Norrby-Teglund A, Koup RA, Liang F, Loré K Blood. 2017;129(14):1991-2001. 92. Wu Y, Ma J, Yang X, Nan F, Zhang T, Ji S, Rao D, Feng H, Gao K, Gu X, Jiang S, Song G, Pan J, Zhang M, Xu Y, Zhang S, Fan Y, Wang X, Zhou J, Yang L, Fan J, Zhang X, Gao Q Cell. 2024;187(6):1422-1439.e1424. 93. Matsushima H, Geng S, Lu R, Okamoto T, Yao Y, Mayuzumi N, Kotol PF, Chojnacki BJ, Miyazaki T, Gallo RL, Takashima A Blood. 2013;121(10):1677-1689. 94. Mysore V, Cullere X, Mears J, Rosetti F, Okubo K, Liew PX, Zhang F, Madera-Salcedo I, Rosenbauer F, Stone RM, Aster JC, von Andrian UH, Lichtman AH, Raychaudhuri S, Mayadas TN Nat Commun. 2021;12(1):4791. 95. Burn GL, Foti A, Marsman G, Patel DF, Zychlinsky A Immunity. 2021;54(7):1377-1391. 96. Reith W, LeibundGut-Landmann S, Waldburger JM Nat Rev Immunol. 2005;5(10):793-806. 97. Hake SB, Masternak K, Kammerbauer C, Janzen C, Reith W, Steimle V Mol Cell Biol. 2000;20(20):7716-7725. 98. Ting JP, Trowsdale J Cell. 2002;109 Suppl:S21-33. 99. Zika E, Ting JP Curr Opin Immunol. 2005;17(1):58-64. 100. LeibundGut-Landmann S, Waldburger JM, Reis e Sousa C, Acha-Orbea H, Reith W Nat Immunol. 2004;5(9):899-908. 101. Zika E, Fauquier L, Vandel L, Ting JP Proc Natl Acad Sci U S A. 2005;102(45):16321-16326. 102. Spilianakis C, Kretsovali A, Agalioti T, Makatounakis T, Thanos D, Papamatheakis J Embo j. 2003;22(19):5125-5136. 103. Qiu Z, Khalife J, Ethiraj P, Jaafar C, Lin AP, Holder KN, Ritter JP, Chiou L, Huelgas-Morales G, Aslam S, Zhang Z, Liu Z, Arya S, Gupta YK, Dahia PLM, Aguiar RCT Sci Adv. 2024;10(28):eadk2091. 104. Devaiah BN, Singer DS Front Immunol. 2013;4:476. 105. Pishesha N, Harmand TJ, Ploegh HL Nat Rev Immunol. 2022;22(12):751-764. 106. Shin DM, Lee CH, Morse HC, 3rd PLoS One. 2011;6(11):e27384. 107. Ascic E, Åkerström F, Sreekumar Nair M, Rosa A, Kurochkin I, Zimmermannova O, Catena X, Rotankova N, Veser C, Rudnik M, Ballocci T, Schärer T, Huang X, de Rosa Torres M, Renaud E, Velasco Santiago M, Met Ö, Askmyr D, Lindstedt M, Greiff L, Ligeon LA, Agarkova I, Svane IM, Pires CF, Rosa FF, Pereira CF Science. 2024:eadn9083. 108. Ohmura-Hoshino M, Matsuki Y, Aoki M, Goto E, Mito M, Uematsu M, Kakiuchi T, Hotta H, Ishido S J Immunol. 2006;177(1):341-354. 109. Shin JS, Ebersold M, Pypaert M, Delamarre L, Hartley A, Mellman I Nature. 2006;444(7115):115-118. 110. van Niel G, Wubbolts R, Ten Broeke T, Buschow SI, Ossendorp FA, Melief CJ, Raposo G, van Balkom BW, Stoorvogel W Immunity. 2006;25(6):885-894. 111. Matsuki Y, Ohmura-Hoshino M, Goto E, Aoki M, Mito-Yoshida M, Uematsu M, Hasegawa T, Koseki H, Ohara O, Nakayama M, Toyooka K, Matsuoka K, Hotta H, Yamamoto A, Ishido S Embo j. 2007;26(3):846-854. 112. Ma JK, Platt MY, Eastham-Anderson J, Shin JS, Mellman I Proc Natl Acad Sci U S A. 2012;109(23):8820-8827. 113. Xu D, Zhang D, Wei W, Zhang C Exp Cell Res. 2024;440(2):114148. 114. Lu J, Jin Z, Jin X, Chen W J Biochem Mol Toxicol. 2024;38(8):e23770. 115. Chang YC, Chen TC, Lee CT, Yang CY, Wang HW, Wang CC, Hsieh SL Blood. 2008;111(10):5054-5063. 116. Hui L, Chen Y Cancer Lett. 2015;368(1):7-13. 117. Papa S, Choy PM, Bubici C Oncogene. 2019;38(13):2223-2240. 118. van Weverwijk A, de Visser KE Nat Rev Cancer. 2023;23(4):193-215. 119. Lofiego MF, Piazzini F, Caruso FP, Marzani F, Solmonese L, Bello E, Celesti F, Costa MC, Noviello T, Mortarini R, Anichini A, Ceccarelli M, Coral S, Di Giacomo AM, Maio M, Covre A J Transl Med. 2024;22(1):223. 120. Holling TM, van Eggermond MC, Jager MJ, van den Elsen PJ Biochem Pharmacol. 2006;72(11):1570-1576. 121. Rogers RS, Horvath CM, Matunis MJ J Biol Chem. 2003;278(32):30091-30097. 122. Heppler LN, Frank DA Trends Cancer. 2017;3(12):816-827. 123. Pitter MR, Kryczek I, Zhang H, Nagarsheth N, Xia H, Wu Z, Tian Y, Okla K, Liao P, Wang W, Zhou J, Li G, Lin H, Vatan L, Grove S, Wei S, Li Y, Zou W Cell Rep. 2024;43(3):113942. 124. Tzortzakaki E, Spilianakis C, Zika E, Kretsovali A, Papamatheakis J Mol Endocrinol. 2003;17(12):2509-2518. 125. Wright KL, Ting JP Trends Immunol. 2006;27(9):405-412. 126. Holtz R, Choi JC, Petroff MG, Piskurich JF, Murphy SP Biol Reprod. 2003;69(3):915-924. 127. Quintanilla M, Montero-Montero L, Renart J, Martín-Villar E Int J Mol Sci. 2019;20(3). 128. Astarita JL, Acton SE, Turley SJ Front Immunol. 2012;3:283. 129. Wu M, Shi Y, Liu Y, Huang H, Che J, Shi J, Xu C CNS Neurosci Ther. 2024;30(3):e14643. 130. Stachowicz-Suhs M, Łabędź N, Anisiewicz A, Banach J, Kłopotowska D, Milczarek M, Piotrowska A, Dzięgiel P, Maciejczyk A, Matkowski R, Wietrzyk J Sci Rep. 2024;14(1):3778. 131. Stone JK, von Muhlinen N, Zhang C, Robles AI, Flis AL, Vega-Valle E, Miyanaga A, Matsumoto M, Greathouse KL, Cooks T, Trinchieri G, Harris CC Oncogenesis. 2024;13(1):13. 132. Li YJ, Zhang C, Martincuks A, Herrmann A, Yu H Nat Rev Cancer. 2023;23(3):115-134. 133. Xiao Y, Yu TJ, Xu Y, Ding R, Wang YP, Jiang YZ, Shao ZM Cell Metab. 2023;35(8):1283-1303. 134. Mortezaee K, Majidpoor J Int Rev Immunol. 2023;42(4):287-303. 135. Kelly B, O’Neill LA Cell Res. 2015;25(7):771-784. 136. Yang J, Ma S, Xu R, Wei Y, Zhang J, Zuo T, Wang Z, Deng H, Yang N, Shen Q J Control Release. 2021;334:21-33. 137. Yang X, Wang Z, Samovich SN, Kapralov AA, Amoscato AA, Tyurin VA, Dar HH, Li Z, Duan S, Kon N, Chen D, Tycko B, Zhang Z, Jiang X, Bayir H, Stockwell BR, Kagan VE, Gu W Cell Metab. 2024;36(4):762-777.e769. 138. Wiernicki B, Maschalidi S, Pinney J, Adjemian S, Vanden Berghe T, Ravichandran KS, Vandenabeele P Nat Commun. 2022;13(1):3676. 139. Huang L, Zhang J, Wei B, Chen S, Zhu S, Qi W, Pei X, Li L, Liu W, Wang Y, Xu X, Xie LG, Chen L Cell Chem Biol. 2023;30(9):1076-1089.e1011. 140. Sui X, Xi X Adv Clin Exp Med. 2024;33(7):739-749. 141. Bahreyni A, Samani SS, Khazaei M, Ryzhikov M, Avan A, Hassanian SM J Cell Physiol. 2018;233(4):2733-2740. 142. Chen JF, Eltzschig HK, Fredholm BB Nat Rev Drug Discov. 2013;12(4):265-286. 143. Yegutkin GG, Boison D Pharmacol Rev. 2022;74(3):797-822. 144. Cronstein BN, Sitkovsky M Nat Rev Rheumatol. 2017;13(1):41-51. 145. Hatfield SM, Kjaergaard J, Lukashev D, Belikoff B, Schreiber TH, Sethumadhavan S, Abbott R, Philbrook P, Thayer M, Shujia D, Rodig S, Kutok JL, Ren J, Ohta A, Podack ER, Karger B, Jackson EK, Sitkovsky M J Mol Med (Berl). 2014;92(12):1283-1292. 146. Sitkovsky MV, Hatfield S, Abbott R, Belikoff B, Lukashev D, Ohta A Cancer Immunol Res. 2014;2(7):598-605. 147. Garay J, D’Angelo JA, Park Y, Summa CM, Aiken ML, Morales E, Badizadegan K, Fiebiger E, Dickinson BL J Immunol. 2010;185(6):3227-3238. 148. Sun C, Wang B, Hao S Front Immunol. 2022;13:837230. 149. Allard B, Allard D, Buisseret L, Stagg J Nat Rev Clin Oncol. 2020;17(10):611-629. 150. Turriani E, Lázaro DF, Ryazanov S, Leonov A, Giese A, Schön M, Schön MP, Griesinger C, Outeiro TF, Arndt-Jovin DJ, Becker D Proc Natl Acad Sci U S A. 2017;114(25):E4971-e4977. 151. Roche PA, Furuta K Nat Rev Immunol. 2015;15(4):203-216. 152. Fokken C, Silbern I, Shomroni O, Pan KT, Ryazanov S, Leonov A, Winkler N, Urlaub H, Griesinger C, Becker D Melanoma Res. 2024. 153. Yan J, Li XY, Roman Aguilera A, Xiao C, Jacoberger-Foissac C, Nowlan B, Robson SC, Beers C, Moesta AK, Geetha N, Teng MWL, Smyth MJ Cancer Immunol Res. 2020;8(3):356-367. 154. Qiao Z, Li X, Kang N, Yang Y, Chen C, Wu T, Zhao M, Liu Y, Ji X Int J Mol Sci. 2019;20(5). 155. Jin D, Fan J, Wang L, Thompson LF, Liu A, Daniel BJ, Shin T, Curiel TJ, Zhang B Cancer Res. 2010;70(6):2245-2255. 156. Häusler SF, Montalbán del Barrio I, Strohschein J, Chandran PA, Engel JB, Hönig A, Ossadnik M, Horn E, Fischer B, Krockenberger M, Heuer S, Seida AA, Junker M, Kneitz H, Kloor D, Klotz KN, Dietl J, Wischhusen J Cancer Immunol Immunother. 2011;60(10):1405-1418. 157. Zhang J, Luo Z, Duan W, Yang K, Ling L, Yan W, Liu R, Wüthrich K, Jiang H, Xie C, Cheng J Eur J Med Chem. 2022;236:114326. 158. Jeffrey JL, Lawson KV, Powers JP J Med Chem. 2020;63(22):13444-13465. 159. Seidah NG, Benjannet S, Wickham L, Marcinkiewicz J, Jasmin SB, Stifani S, Basak A, Prat A, Chretien M Proc Natl Acad Sci U S A. 2003;100(3):928-933. 160. Wang H, Zhang X, Zhang Y, Shi T, Zhang Y, Song X, Liu B, Wang Y, Wei J BMC Cancer. 2024;24(1):445. 161. Zak J, Pratumchai I, Marro BS, Marquardt KL, Zavareh RB, Lairson LL, Oldstone MBA, Varner JA, Hegerova L, Cao Q, Farooq U, Kenkre VP, Bachanova V, Teijaro JR Science. 2024;384(6702):eade8520. 162. Chiappinelli KB, Strissel PL, Desrichard A, Li H, Henke C, Akman B, Hein A, Rote NS, Cope LM, Snyder A, Makarov V, Budhu S, Slamon DJ, Wolchok JD, Pardoll DM, Beckmann MW, Zahnow CA, Merghoub T, Chan TA, Baylin SB, Strick R Cell. 2015;162(5):974-986. 163. Chiappinelli KB, Zahnow CA, Ahuja N, Baylin SB Cancer Res. 2016;76(7):1683-1689. 164. Ganai SA, Shah BA, Yatoo MA Adv Cancer Res. 2023;158:163-198. 165. Tai SK, Chang HC, Lan KL, Lee CT, Yang CY, Chen NJ, Chou TY, Tarng DC, Hsieh SL J Immunol. 2012;188(5):2464-2471. 166. Göttlicher M, Minucci S, Zhu P, Krämer OH, Schimpf A, Giavara S, Sleeman JP, Lo Coco F, Nervi C, Pelicci PG, Heinzel T Embo j. 2001;20(24):6969-6978. 167. Ducellier S, Demeules M, Letribot B, Gaetani M, Michaudel C, Sokol H, Hamze A, Alami M, Nascimento M, Apcher S J Immunother Cancer. 2024;12(4). 168. James JL, Taylor BC, Axelrod ML, Sun X, Guerin LN, Gonzalez-Ericsson PI, Wang Y, Sanchez V, Fahey CC, Sanders ME, Xu Y, Hodges E, Johnson DB, Balko JM J Immunother Cancer. 2023;11(11). 169. DuCote TJ, Song X, Naughton KJ, Chen F, Plaugher DR, Childress AR, Gellert AR, Skaggs EM, Qu X, Liu J, Liu J, Li F, Wong KK, Brainson CF Cancer Res Commun. 2024;4(2):388-403. 170. Buteyn NJ, Burke CG, Sartori VJ, Deering-Gardner E, DeBruine ZJ, Kamarudin D, Chandler DP, Monovich AC, Perez MW, Yi JS, Ries RE, Alonzo TA, Ryan RJ, Meshinchi S, Triche TJ, Jr. bioRxiv. 2024. 171. Kapoor S, Gustafson T, Zhang M, Chen YS, Li J, Nguyen N, Perez JET, Dashwood WM, Rajendran P, Dashwood RH Cancers (Basel). 2021;13(6). 172. Rajendran P, Johnson G, Li L, Chen YS, Dashwood M, Nguyen N, Ulusan A, Ertem F, Zhang M, Li J, Sun D, Huang Y, Wang S, Leung HC, Lieberman D, Beaver L, Ho E, Bedford M, Chang K, Vilar E, Dashwood R Cancer Res. 2019;79(5):918-927. 173. Mazur PK, Herner A, Mello SS, Wirth M, Hausmann S, Sánchez-Rivera FJ, Lofgren SM, Kuschma T, Hahn SA, Vangala D, Trajkovic-Arsic M, Gupta A, Heid I, Noël PB, Braren R, Erkan M, Kleeff J, Sipos B, Sayles LC, Heikenwalder M, Heßmann E, Ellenrieder V, Esposito I, Jacks T, Bradner JE, Khatri P, Sweet-Cordero EA, Attardi LD, Schmid RM, Schneider G, Sage J, Siveke JT Nat Med. 2024. 174. Liu D, Liang CH, Huang B, Zhuang X, Cui W, Yang L, Yang Y, Zhang Y, Fu X, Zhang X, Du L, Gu W, Wang X, Yin C, Chai R, Chu B Adv Sci (Weinh). 2023;10(6):e2204006. 175. Wan C, Sun Y, Tian Y, Lu L, Dai X, Meng J, Huang J, He Q, Wu B, Zhang Z, Jiang K, Hu D, Wu G, Lovell JF, Jin H, Yang K Sci Adv. 2020;6(13):eaay9789. 176. Deng Z, Li B, Yang M, Lu L, Shi X, Lovell JF, Zeng X, Hu W, Jin H J Nanobiotechnology. 2024;22(1):225. 177. Masad RJ, Idriss I, Mohamed YA, Al-Sbiei A, Bashir G, Al-Marzooq F, Altahrawi A, Fernandez-Cabezudo MJ, Al-Ramadi BK Front Immunol. 2024;15:1354297. 178. Kumar S, Saini RV, Mahindroo N Biomed Pharmacother. 2017;96:1491-1500. 179. Melero I, Berman DM, Aznar MA, Korman AJ, Pérez Gracia JL, Haanen J Nat Rev Cancer. 2015;15(8):457-472. 180. Xie N, Shen G, Gao W, Huang Z, Huang C, Fu L Signal Transduct Target Ther. 2023;8(1):9. 181. Yarchoan M, Johnson BA, 3rd, Lutz ER, Laheru DA, Jaffee EM Nat Rev Cancer. 2017;17(9):569. 182. Hu Z, Leet DE, Allesøe RL, Oliveira G, Li S, Luoma AM, Liu J, Forman J, Huang T, Iorgulescu JB, Holden R, Sarkizova S, Gohil SH, Redd RA, Sun J, Elagina L, Giobbie-Hurder A, Zhang W, Peter L, Ciantra Z, Rodig S, Olive O, Shetty K, Pyrdol J, Uduman M, Lee PC, Bachireddy P, Buchbinder EI, Yoon CH, Neuberg D, Pentelute BL, Hacohen N, Livak KJ, Shukla SA, Olsen LR, Barouch DH, Wucherpfennig KW, Fritsch EF, Keskin DB, Wu CJ, Ott PA Nat Med. 2021;27(3):515-525. 183. Keskin DB, Anandappa AJ, Sun J, Tirosh I, Mathewson ND, Li S, Oliveira G, Giobbie-Hurder A, Felt K, Gjini E, Shukla SA, Hu Z, Li L, Le PM, Allesøe RL, Richman AR, Kowalczyk MS, Abdelrahman S, Geduldig JE, Charbonneau S, Pelton K, Iorgulescu JB, Elagina L, Zhang W, Olive O, McCluskey C, Olsen LR, Stevens J, Lane WJ, Salazar AM, Daley H, Wen PY, Chiocca EA, Harden M, Lennon NJ, Gabriel S, Getz G, Lander ES, Regev A, Ritz J, Neuberg D, Rodig SJ, Ligon KL, Suvà ML, Wucherpfennig KW, Hacohen N, Fritsch EF, Livak KJ, Ott PA, Wu CJ, Reardon DA Nature. 2019;565(7738):234-239. 184. Ott PA, Hu Z, Keskin DB, Shukla SA, Sun J, Bozym DJ, Zhang W, Luoma A, Giobbie-Hurder A, Peter L, Chen C, Olive O, Carter TA, Li S, Lieb DJ, Eisenhaure T, Gjini E, Stevens J, Lane WJ, Javeri I, Nellaiappan K, Salazar AM, Daley H, Seaman M, Buchbinder EI, Yoon CH, Harden M, Lennon N, Gabriel S, Rodig SJ, Barouch DH, Aster JC, Getz G, Wucherpfennig K, Neuberg D, Ritz J, Lander ES, Fritsch EF, Hacohen N, Wu CJ Nature. 2017;547(7662):217-221. 185. Ott PA, Hu-Lieskovan S, Chmielowski B, Govindan R, Naing A, Bhardwaj N, Margolin K, Awad MM, Hellmann MD, Lin JJ, Friedlander T, Bushway ME, Balogh KN, Sciuto TE, Kohler V, Turnbull SJ, Besada R, Curran RR, Trapp B, Scherer J, Poran A, Harjanto D, Barthelme D, Ting YS, Dong JZ, Ware Y, Huang Y, Huang Z, Wanamaker A, Cleary LD, Moles MA, Manson K, Greshock J, Khondker ZS, Fritsch E, Rooney MS, DeMario M, Gaynor RB, Srinivasan L Cell. 2020;183(2):347-362.e324. 186. Lai YP, Lin CC, Liao WJ, Tang CY, Chen SC PLoS One. 2009;4(11):e7766. 187. Sillito F, Holler A, Stauss HJ Cells. 2020;9(7). 188. Viborg N, Pavlidis MA, Barrio-Calvo M, Friis S, Trolle T, Sørensen AB, Thygesen CB, Kofoed SV, Kleine-Kohlbrecher D, Hadrup SR, Rønø B NPJ Vaccines. 2023;8(1):77. 189. Sharif E, Nezafat N, Ahmadi FM, Mohit E Appl Biochem Biotechnol. 2024. 190. Moges Eskeziyaw B, Waihenya R, Maina N, Muuo Nzou S Helicobacter. 2024;29(3):e13104. 191. Sultan H, Takeuchi Y, Ward JP, Sharma N, Liu TT, Sukhov V, Firulyova M, Song Y, Ameh S, Brioschi S, Khantakova D, Arthur CD, White JM, Kohlmiller H, Salazar AM, Burns R, Costa HA, Moynihan KD, Yeung YA, Djuretic I, Schumacher TN, Sheehan KCF, Colonna M, Allison JP, Murphy KM, Artyomov MN, Schreiber RD Nature. 2024;632(8023):182-191. 192. He K, Wan T, Wang D, Hu J, Zhou T, Tao W, Wei Z, Lu Q, Zhou R, Tian Z, Flavell RA, Zhu S Cell. 2023;186(14):3033-3048.e3020. 193. Wilson NS, Villadangos JA Adv Immunol. 2005;86:241-305. 194. Terbuch A, Lopez J Vaccines (Basel). 2018;6(3). 195. Markov OV, Mironova NL, Sennikov SV, Vlassov VV, Zenkova MA PLoS One. 2015;10(9):e0136911. 196. Kurilin V, Alshevskaya A, Sennikov S Biomedicines. 2024;12(3). 197. Chen J, Guo XZ, Li HY, Wang D, Shao XD Exp Biol Med (Maywood). 2015;240(10):1310-1318. 198. Van Nuffel AM, Corthals J, Neyns B, Heirman C, Thielemans K, Bonehill A Methods Mol Biol. 2010;629:405-452. 199. Zitvogel L, Regnault A, Lozier A, Wolfers J, Flament C, Tenza D, Ricciardi-Castagnoli P, Raposo G, Amigorena S Nat Med. 1998;4(5):594-600. 200. Feola S, Hamdan F, Russo S, Chiaro J, Fusciello M, Feodoroff M, Antignani G, D’Alessio F, Mölsä R, Stigzelius V, Bottega P, Pesonen S, Leusen J, Grönholm M, Cerullo V J Immunother Cancer. 2024;12(3). 201. Shi Q, Wang Q, Shen Y, Chen S, Gan S, Lin T, Song F, Ma Y Mol Immunol. 2024;173:10-19. 202. Tao Y, Lin F, Li T, Xie J, Shen C, Zhu Z Oncol Res. 2013;21(6):307-316. 203. Azzi L, Celesti F, Chiaravalli AM, Shaik AKB, Shallak M, Gatta A, Battaglia P, La Rosa S, Tagliabue A, Accolla RS, Forlani G Front Immunol. 2024;15:1387835. 204. Jenika D, Pounraj S, Wibowo D, Flaxl LM, Rehm BHA, Mintern JD NPJ Vaccines. 2024;9(1):18. 205. Chung JT, Rafiei M, Chau Y Biomater Sci. 2024;12(7):1771-1787. 206. Costantini F, Barbieri G Cell Signal. 2017;36:189-203. 207. Johnson DB, Nixon MJ, Wang Y, Wang DY, Castellanos E, Estrada MV, Ericsson-Gonzalez PI, Cote CH, Salgado R, Sanchez V, Dean PT, Opalenik SR, Schreeder DM, Rimm DL, Kim JY, Bordeaux J, Loi S, Horn L, Sanders ME, Ferrell PB, Jr., Xu Y, Sosman JA, Davis RS, Balko JM JCI Insight. 2018;3(24). 208. Kozłowski M, Borzyszkowska D, Cymbaluk-Płoska A Biomedicines. 2022;10(11). 209. Schöffski P, Tan DSW, Martín M, Ochoa-de-Olza M, Sarantopoulos J, Carvajal RD, Kyi C, Esaki T, Prawira A, Akerley W, De Braud F, Hui R, Zhang T, Soo RA, Maur M, Weickhardt A, Krauss J, Deschler-Baier B, Lau A, Samant TS, Longmire T, Chowdhury NR, Sabatos-Peyton CA, Patel N, Ramesh R, Hu T, Carion A, Gusenleitner D, Yerramilli-Rao P, Askoxylakis V, Kwak EL, Hong DS J Immunother Cancer. 2022;10(2). 210. Zuo D, Zhu Y, Wang K, Qin Y, Su Y, Lan S, Li Y, Dong S, Liang Y, Feng M Biomed Pharmacother. 2024;175:116782. 211. Dai T, Sun H, Liban T, Vicente-Suarez I, Zhang B, Song Y, Jiang Z, Yu J, Sheng J, Lv B Sci Rep. 2024;14(1):10661. 212. Silberstein JL, Du J, Chan KW, Frank JA, Mathews, II, Kim YB, You J, Lu Q, Liu J, Philips EA, Liu P, Rao E, Fernandez D, Rodriguez GE, Kong XP, Wang J, Cochran JR Proc Natl Acad Sci U S A. 2024;121(12):e2310866121. 213. Cheng M, Chen S, Li K, Wang G, Xiong G, Ling R, Zhang C, Zhang Z, Han H, Chen Z, Wang X, Liang Y, Tian G, Zhou R, Zhu Y, Ma J, Liu J, Lin S, Xu H, Chen D, Li Y, Peng L Nat Commun. 2024;15(1):2818. 214. Kong Y, Li C, Liu J, Wu S, Zhang M, Allison DB, Hassan F, He D, Wang X, Mao F, Zhang Q, Zhang Y, Li Z, Wang C, Liu X PLoS Genet. 2024;20(6):e1011309. 215. Bu Y, Liu Q, Shang Y, Zhao Z, Sun H, Chen F, Ma Q, Song J, Cui L, Sun E, Luo Y, Shu L, Jing H, Tan X Int J Biol Macromol. 2024;270(Pt 1):131949. 216. van den Bulk J, Verdegaal EM, de Miranda NF Open Biol. 2018;8(6). 217. Huang J, Wang K, Wu S, Zhang J, Chen X, Lei S, Wu J, Men K, Duan X Mol Pharm. 2024;21(1):267-282. 218. Song X, Zhou X, Pan Y, Liang K, Luo Y, Xie W, Lv Z, Yang D, Wang Y, Wu XS, Wu Y, Wei J Advanced Functional Materials. 2023;33(47):2306734. 219. Yang J, Ren B, Yin X, Xiang L, Hua Y, Huang X, Wang H, Mao Z, Chen W, Deng J Adv Mater. 2024:e2402720. 220. Simões MM, Paiva KLR, de Souza IF, Mello VC, Martins da Silva IG, Souza PEN, Muehlmann LA, Báo SN Pharmaceutics. 2024;16(7). 221. Park IA, Hwang SH, Song IH, Heo SH, Kim YA, Bang WS, Park HS, Lee M, Gong G, Lee HJ PLoS One. 2017;12(8):e0182786. 222. Roemer MGM, Redd RA, Cader FZ, Pak CJ, Abdelrahman S, Ouyang J, Sasse S, Younes A, Fanale M, Santoro A, Zinzani PL, Timmerman J, Collins GP, Ramchandren R, Cohen JB, De Boer JP, Kuruvilla J, Savage KJ, Trneny M, Ansell S, Kato K, Farsaci B, Sumbul A, Armand P, Neuberg DS, Pinkus GS, Ligon AH, Rodig SJ, Shipp MA J Clin Oncol. 2018;36(10):942-950. 223. Rodig SJ, Gusenleitner D, Jackson DG, Gjini E, Giobbie-Hurder A, Jin C, Chang H, Lovitch SB, Horak C, Weber JS, Weirather JL, Wolchok JD, Postow MA, Pavlick AC, Chesney J, Hodi FS Sci Transl Med. 2018;10(450). 224. Amrane K, Le Meur C, Besse B, Hemon P, Le Noac’h P, Pradier O, Berthou C, Abgral R, Uguen A Front Immunol. 2023;14:1285895. 225. Robert C, Long GV, Brady B, Dutriaux C, Maio M, Mortier L, Hassel JC, Rutkowski P, McNeil C, Kalinka-Warzocha E, Savage KJ, Hernberg MM, Lebbé C, Charles J, Mihalcioiu C, Chiarion-Sileni V, Mauch C, Cognetti F, Arance A, Schmidt H, Schadendorf D, Gogas H, Lundgren-Eriksson L, Horak C, Sharkey B, Waxman IM, Atkinson V, Ascierto PA N Engl J Med. 2015;372(4):320-330. 226. Kaunitz GJ, Cottrell TR, Lilo M, Muthappan V, Esandrio J, Berry S, Xu H, Ogurtsova A, Anders RA, Fischer AH, Kraft S, Gerstenblith MR, Thompson CL, Honda K, Cuda JD, Eberhart CG, Handa JT, Lipson EJ, Taube JM Lab Invest. 2017;97(9):1063-1071. 227. Johnson DB, Bordeaux J, Kim JY, Vaupel C, Rimm DL, Ho TH, Joseph RW, Daud AI, Conry RM, Gaughan EM, Hernandez-Aya LF, Dimou A, Funchain P, Smithy J, Witte JS, McKee SB, Ko J, Wrangle JM, Dabbas B, Tangri S, Lameh J, Hall J, Markowitz J, Balko JM, Dakappagari N Clin Cancer Res. 2018;24(21):5250-5260. 228. Sun X, Kennedy LC, Gonzalez-Ericsson PI, Sanchez V, Sanders M, Perou CM, Troester MA, Balko JM, Reid SA Clin Cancer Res. 2024. 229. Huang AC, Zappasodi R Nat Immunol. 2022;23(5):660-670. 230. Davis AA, Patel VG J Immunother Cancer. 2019;7(1):278. 231. Lu S, Stein JE, Rimm DL, Wang DW, Bell JM, Johnson DB, Sosman JA, Schalper KA, Anders RA, Wang H, Hoyt C, Pardoll DM, Danilova L, Taube JM JAMA Oncol. 2019;5(8):1195-1204. 232. Chen Y, Wang D, Li Y, Qi L, Si W, Bo Y, Chen X, Ye Z, Fan H, Liu B, Liu C, Zhang L, Zhang X, Li Z, Zhu L, Wu A, Zhang Z Cancer Cell. 2024;42(7):1268-1285.e1267. 233. Caushi JX, Zhang J, Ji Z, Vaghasia A, Zhang B, Hsiue EH, Mog BJ, Hou W, Justesen S, Blosser R, Tam A, Anagnostou V, Cottrell TR, Guo H, Chan HY, Singh D, Thapa S, Dykema AG, Burman P, Choudhury B, Aparicio L, Cheung LS, Lanis M, Belcaid Z, El Asmar M, Illei PB, Wang R, Meyers J, Schuebel K, Gupta A, Skaist A, Wheelan S, Naidoo J, Marrone KA, Brock M, Ha J, Bush EL, Park BJ, Bott M, Jones DR, Reuss JE, Velculescu VE, Chaft JE, Kinzler KW, Zhou S, Vogelstein B, Taube JM, Hellmann MD, Brahmer JR, Merghoub T, Forde PM, Yegnasubramanian S, Ji H, Pardoll DM, Smith KN Nature. 2021;598(7881):E1. 234. Bassez A, Vos H, Van Dyck L, Floris G, Arijs I, Desmedt C, Boeckx B, Vanden Bempt M, Nevelsteen I, Lambein K, Punie K, Neven P, Garg AD, Wildiers H, Qian J, Smeets A, Lambrechts D Nat Med. 2021;27(5):820-832. 235. Luoma AM, Suo S, Wang Y, Gunasti L, Porter CBM, Nabilsi N, Tadros J, Ferretti AP, Liao S, Gurer C, Chen YH, Criscitiello S, Ricker CA, Dionne D, Rozenblatt-Rosen O, Uppaluri R, Haddad RI, Ashenberg O, Regev A, Van Allen EM, MacBeath G, Schoenfeld JD, Wucherpfennig KW Cell. 2022;185(16):2918-2935.e2929. 236. Rahim MK, Okholm TLH, Jones KB, McCarthy EE, Liu CC, Yee JL, Tamaki SJ, Marquez DM, Tenvooren I, Wai K, Cheung A, Davidson BR, Johri V, Samad B, O’Gorman WE, Krummel MF, van Zante A, Combes AJ, Angelo M, Fong L, Algazi AP, Ha P, Spitzer MH Cell. 2023;186(6):1127-1143.e1118. 237. Pan B, Yan S, Yuan L, Xiang H, Ju M, Xu S, Jia W, Li J, Zhao Q, Zheng M J Pathol. 2024;263(3):372-385. 238. Blum JS, Wearsch PA, Cresswell P Annu Rev Immunol. 2013;31:443-473. 239. Godkin AJ, Smith KJ, Willis A, Tejada-Simon MV, Zhang J, Elliott T, Hill AV J Immunol. 2001;166(11):6720-6727. 240. Holland CJ, Dolton G, Scurr M, Ladell K, Schauenburg AJ, Miners K, Madura F, Sewell AK, Price DA, Cole DK, Godkin AJ J Immunol. 2015;195(12):5827-5836. 241. Wan X, Vomund AN, Peterson OJ, Chervonsky AV, Lichti CF, Unanue ER Nat Immunol. 2020;21(4):455-463. 242. Groeger S, Jarzina F, Domann E, Meyle J BMC Immunol. 2017;18(1):1. 243. Abelin JG, Keskin DB, Sarkizova S, Hartigan CR, Zhang W, Sidney J, Stevens J, Lane W, Zhang GL, Eisenhaure TM, Clauser KR, Hacohen N, Rooney MS, Carr SA, Wu CJ Immunity. 2017;46(2):315-326. 244. Purcell AW, Ramarathinam SH, Ternette N Nat Protoc. 2019;14(6):1687-1707. 245. Zhang X, Qi Y, Zhang Q, Liu W Biomed Pharmacother. 2019;120:109542. 246. Huisman BD, Dai Z, Gifford DK, Birnbaum ME Elife. 2022;11. 247. Abelin JG, Harjanto D, Malloy M, Suri P, Colson T, Goulding SP, Creech AL, Serrano LR, Nasir G, Nasrullah Y, McGann CD, Velez D, Ting YS, Poran A, Rothenberg DA, Chhangawala S, Rubinsteyn A, Hammerbacher J, Gaynor RB, Fritsch EF, Greshock J, Oslund RC, Barthelme D, Addona TA, Arieta CM, Rooney MS Immunity. 2019;51(4):766-779.e717. 248. Parizi FM, Marzella DF, Ramakrishnan G, t Hoen PAC, Karimi-Jafari MH, Xue LC Front Immunol. 2023;14:1285899. 249. Carter JA, Matta B, Battaglia J, Somerville C, Harris BD, LaPan M, Atwal GS, Barnes BJ J Immunother Cancer. 2023;11(12). 250. Jiang W, Boder ET Proc Natl Acad Sci U S A. 2010;107(30):13258-13263. 251. Yang Y, Wei Z, Cia G, Song X, Pucci F, Rooman M, Xue F, Hou Q Front Immunol. 2024;15:1293706. 252. Kawakita S, Shen A, Chao CC, Wang Z, Cheng S, Li B, Jiang C Antib Ther. 2024;7(2):177-186. 253. Racle J, Gfeller D Methods Mol Biol. 2024;2809:215-235. 254. Korompoki E, Filippidis FT, Nielsen PB, Del Giudice A, Lip GYH, Kuramatsu JB, Huttner HB, Fang J, Schulman S, Martí-Fàbregas J, Gathier CS, Viswanathan A, Biffi A, Poli D, Weimar C, Malzahn U, Heuschmann P, Veltkamp R Neurology. 2017;89(7):687-696. 255. Chen B, Khodadoust MS, Olsson N, Wagar LE, Fast E, Liu CL, Muftuoglu Y, Sworder BJ, Diehn M, Levy R, Davis MM, Elias JE, Altman RB, Alizadeh AA Nat Biotechnol. 2019;37(11):1332-1343. 256. Santich BH, Liu H, Liu C, Cheung NK Methods Mol Biol. 2015;1348:191-204. 257. Joglekar AV, Li G Nat Methods. 2021;18(8):873-880. 258. Kohlgruber AC, Dezfulian MH, Sie BM, Wang CI, Kula T, Laserson U, Larman HB, Elledge SJ Nat Biotechnol. 2024. 259. Jiang F, Guo Y, Ma H, Na S, Zhong W, Han Y, Wang T, Huang J Brief Bioinform. 2024;25(4). 260. Dash P, Fiore-Gartland AJ, Hertz T, Wang GC, Sharma S, Souquette A, Crawford JC, Clemens EB, Nguyen THO, Kedzierska K, La Gruta NL, Bradley P, Thomas PG Nature. 2017;547(7661):89-93. 261. Jokinen E, Huuhtanen J, Mustjoki S, Heinonen M, Lähdesmäki H PLoS Comput Biol. 2021;17(3):e1008814. 262. Lu T, Zhang Z, Zhu J, Wang Y, Jiang P, Xiao X, Bernatchez C, Heymach JV, Gibbons DL, Wang J, Xu L, Reuben A, Wang T Nat Mach Intell. 2021;3(10):864-875. 263. Sidhom JW, Larman HB, Pardoll DM, Baras AS Nat Commun. 2021;12(1):1605. 264. Springer I, Besser H, Tickotsky-Moskovitz N, Dvorkin S, Louzoun Y Front Immunol. 2020;11:1803. 265. Tong Y, Wang J, Zheng T, Zhang X, Xiao X, Zhu X, Lai X, Liu X Comput Biol Chem. 2020;87:107281. 266. Zdinak PM, Trivedi N, Grebinoski S, Torrey J, Martinez EZ, Martinez S, Hicks L, Ranjan R, Makani VKK, Roland MM, Kublo L, Arshad S, Anderson MS, Vignali DAA, Joglekar AV Nat Methods. 2024;21(5):846-856. 267. In: Anaya JM, Shoenfeld Y, Rojas-Villarraga A, Levy RA, Cervera R, eds. Autoimmunity: From Bench to Bedside . Bogota (Colombia): El Rosario University Press © 2013 Universidad del Rosario.; 2013. 268. Arnold PY, La Gruta NL, Miller T, Vignali KM, Adams PS, Woodland DL, Vignali DA J Immunol. 2002;169(2):739-749. 269. Nicholson LB Essays Biochem. 2016;60(3):275-301. 270. Logunova N, Korotetskaya M, Polshakov V, Apt A PLoS Genet. 2015;11(11):e1005672. 271. Racle J, Guillaume P, Schmidt J, Michaux J, Larabi A, Lau K, Perez MAS, Croce G, Genolet R, Coukos G, Zoete V, Pojer F, Bassani-Sternberg M, Harari A, Gfeller D Immunity. 2023;56(6):1359-1375.e1313. 272. Zeng Z, Gu SS, Ouardaoui N, Tymm C, Yang L, Wong CJ, Li D, Zhang W, Wang X, Weirather JL, Rodig SJ, Hodi FS, Brown M, Liu XS Cancer Immunol Res. 2022;10(12):1559-1569. 273. Claeys A, Van den Eynden J Commun Med (Lond). 2024;4(1):184. 274. Mendez R, Aptsiauri N, Del Campo A, Maleno I, Cabrera T, Ruiz-Cabello F, Garrido F, Garcia-Lora A Cancer Immunol Immunother. 2009;58(9):1507-1515. 275. Liu D, Schilling B, Liu D, Sucker A, Livingstone E, Jerby-Arnon L, Zimmer L, Gutzmer R, Satzger I, Loquai C, Grabbe S, Vokes N, Margolis CA, Conway J, He MX, Elmarakeby H, Dietlein F, Miao D, Tracy A, Gogas H, Goldinger SM, Utikal J, Blank CU, Rauschenberg R, von Bubnoff D, Krackhardt A, Weide B, Haferkamp S, Kiecker F, Izar B, Garraway L, Regev A, Flaherty K, Paschen A, Van Allen EM, Schadendorf D Nat Med. 2019;25(12):1916-1927. 276. Langenbach M, Giesler S, Richtsfeld S, Costa-Pereira S, Rindlisbacher L, Wertheimer T, Braun LM, Andrieux G, Duquesne S, Pfeifer D, Woessner NM, Menssen HD, Taromi S, Duyster J, Börries M, Brummer T, Blazar BR, Minguet S, Turko P, Levesque MP, Becher B, Zeiser R Mol Cancer Res. 2023;21(8):849-864. 277. Tarhini AA, Lee SJ, Tan AC, El Naqa IM, Stephen Hodi F, Butterfield LH, LaFramboise WA, Storkus WJ, Karunamurthy AD, Conejo-Garcia JR, Hwu P, Streicher H, Sondak VK, Kirkwood JM J Immunother Cancer. 2022;10(1). 278. Gonzalez-Ericsson PI, Wulfkhule JD, Gallagher RI, Sun X, Axelrod ML, Sheng Q, Luo N, Gomez H, Sanchez V, Sanders M, Pusztai L, Petricoin E, Blenman KRM, Balko JM Clin Cancer Res. 2021;27(19):5299-5306. 279. Wang XQ, Danenberg E, Huang CS, Egle D, Callari M, Bermejo B, Dugo M, Zamagni C, Thill M, Anton A, Zambelli S, Russo S, Ciruelos EM, Greil R, Győrffy B, Semiglazov V, Colleoni M, Kelly CM, Mariani G, Del Mastro L, Biasi O, Seitz RS, Valagussa P, Viale G, Gianni L, Bianchini G, Ali HR Nature. 2023;621(7980):868-876. 280. Stewart RL, Matynia AP, Factor RE, Varley KE Scientific Reports. 2020;10(1):6598. 281. Lei PJ, Pereira ER, Andersson P, Amoozgar Z, Van Wijnbergen JW, O’Melia MJ, Zhou H, Chatterjee S, Ho WW, Posada JM, Kumar AS, Morita S, Menzel L, Chung C, Ergin I, Jones D, Huang P, Beyaz S, Padera TP J Exp Med. 2023;220(9). 282. Lamberti MJ, Montico B, Ravo M, Nigro A, Giurato G, Iorio R, Tarallo R, Weisz A, Stellato C, Steffan A, Dolcetti R, Casolaro V, Faè DA, Dal Col J Biomedicines. 2022;10(8). 283. Johnson AM, Bullock BL, Neuwelt AJ, Poczobutt JM, Kaspar RE, Li HY, Kwak JW, Hopp K, Weiser-Evans MCM, Heasley LE, Schenk EL, Clambey ET, Nemenoff RA J Immunol. 2020;204(8):2295-2307. 284. Huff AL, Longway G, Mitchell JT, Andaloori L, Davis-Marcisak E, Chen F, Lyman MR, Wang R, Mathew J, Barrett B, Rahman S, Leatherman J, Yarchoan M, Azad NS, Yegnasubramanian S, Kagohara LT, Fertig EJ, Jaffee EM, Armstrong TD, Zaidi N JCI Insight. 2023;8(23). 285. Bunse L, Rupp AK, Poschke I, Bunse T, Lindner K, Wick A, Blobner J, Misch M, Tabatabai G, Glas M, Schnell O, Gempt J, Denk M, Reifenberger G, Bendszus M, Wuchter P, Steinbach JP, Wick W, Platten M Neurol Res Pract. 2022;4(1):20. 286. Bai S, Jiang H, Song Y, Zhu Y, Qin M, He C, Du G, Sun X J Control Release. 2022;344:134-146. 287. Samman N, Mohabatkar H, Behbahani M, Ganjlikhani Hakemi M PLoS One. 2024;19(6):e0306117. 288. Kittler JM, Sommer J, Fischer A, Britting S, Karg MM, Bock B, Atreya I, Heindl LM, Mackensen A, Bosch JJ Oncotarget. 2019;10(19):1812-1828. Tables Table 1： MHC II components in human and mouse | Similarities | Molecular structure | It consists of two non-covalently linked polypeptide chains, called α chain and β chain 267 . | | | Functional domain | The extracellular region has similar immunoglobulin folding structure 267 . | || | Cells expressing MHC II | professional APCs (e.g., B cells, DCs, macrophages) 151 atypical APCs (e.g., hematopoietic and solid tumor cells) 16 | || | Function | MHC II presented exogenous antigens to CD4 + T cells to activate an adaptive immune response. | || | Differences | Gene coding | The D-region | The genes encoded | | genes in the HLA complex code for the HLA-DR, DP, and DQ antigens 21 . | in the H-2 complex include H-2A(I-A), H-2E(I-E), and H-2P 268 . | || | Gene length | The α chain is about 34 kD and the β chain is about 29 kD 251 . | The α chain is about 33 kD and the β chain is about 28 kD 269 . | | | Chromosome localization | Short arm of chromosome 6 (6P21.31) 105 | Chromosome 17 270 | | | Degree of gene polymorphism | High gene polymorphism with a large number of alleles 251 | Gene polymorphism is relatively low and the number of alleles is small 271 | Table2: MHC II expression on tumor cells | Melanoma | B16F10 cells were divided into high and low MHC II subgroups | High expression of MHC II was positively correlated with anti-PD-1 immunotherapy response, 25-week PFS, and OS | Hippo signaling pathway | 272 | | Different MGBS-II | MGBS-II is an independent TMB predictor of anti-PD-1 immunotherapy response in melanoma. High MGBS-II was associated with failure of response to ICB therapy. | — | 273 | | | Four different HLA II tumor phenotypes were defined in 12 cell lines. Phenotype 1: HLA II expression was negative (28.5%) before and after IFNγ treatment. Phenotype 2: Lack of constitutive HLA II expression, with IFNγ -induced HLA II subtype (28.5%); Phenotype 3: positive for HLA-DR and HLA-DP (19%); Only HLA-DP positive (5%); Phenotype 4: Constitutive surface expression of three HLA II subtypes (HLA-DR, HLA-DP, and HLA-DQ) (19%) | HLA II expression was significantly associated with longer survival. | HLA I is positively correlated with HLA II expression, and there is a co-regulatory mechanism of HLA I and HLA II expression in melanoma cells. | 274 | | | Based on the CCLE Melanoma Panel of 60 cell lines, the prototype MHC II molecule HLA-DRA is absent in about 50% of cell lines and highly expressed in 50% of cell lines. | In anti-PD-1-treated melanoma patients, MHC II positivity on tumor cells was associated with treatment response, PFS andOS, as well as CD4 + and CD8 + tumor infiltration. | IFNγ induces tumor cells to express MHC II. | 73 | | | In melanoma patients treated with anti-PD-1 ICB (n = 144), the expression of 13 HLA II-associated genes was higher in the responders. | It is associated with primary resistance to anti-PD-1 ICB and can predict the response. | MHC II transcriptome expression was associated with the expression of CD4 and the cytolytic molecules PRF1 and GZMA. | 275 | | | Low expression | The patients had primary and secondary resistance to ICB and decreased PFS. | MDM2 inhibits p53 transcriptional activation and MHC II and IL-15 production. | 276 | | | Patients with MUP tumors had significantly higher MHC II scores than patients with known primary melanoma. | The prognosis of MUP patients is obviously better, and TME and circulating immune activation are significantly enhanced. | It may be related to the significant increase of IL-2R. | 277 | | | Low expression | The patient is resistant to immunotherapy. | EZH2 may lead to decreased expression of MHC II through CIITA chromatin accessibility. | 168 | | | Breast cancer | 15% of TNBCs showed ≥5% HLA-DR (MHC II + ）. | Quantitative evaluation of tumor cells MHC II can predict the benefit of NAC with PD-1/PD-L1 inhibitors. | Expression can be driven by inflammatory signals, such as IFN. | 278,279 | | NanoString DSP analyzed the elevated expression of HLA-DR in tumor epithelial cells of a subgroup of TNBCs. HLA-DR expression was elevated in the tumors of patients with long-term DFS compared to patients with recurrence. | The expression level of MHC II was positively correlated with DFS. | — | 280 | | | MHC II is highly expressed in metastatic lymph node cancer cells of breast cancer. | The lack of expression of co-stimulatory molecules in MHC II + cancer cells led to the expansion of Tregs and the reduction of CD4 + T cells in TDLN, and the expression of MHC II cancer cells promoted the metastasis and immune escape of TDLN. | Induction of IFNγ signaling pathway. | 281 | | | Low Expression | Enhance the inhibition of ICD on tumor. | miR4284 and miR-212-3p may be involved in MHC II downregulation. | 282 | | | CHL | The expression of PD-L1 in CHL cells was positively correlated with the expression of CHL MHC II. | CHL is very sensitive to PD-1 inhibition. | PD-L1 in the TME with links to MHC II expression, Th recruitment and the Tregs infiltrate. | 67 | | CHL was found to be MHC II positive in most clinical samples (54/85). | Expression of MHC II by tumor cells contributes to spontaneous and PD-1 blockade mediated anti-tumor immunity. | — | 68 | | | CRC | Clinical samples showed that about 60% (148 cases) of CRC cells expressed HLA-DR. | Patients who express HLA-DR have a better prognosis and may be an independent predictor of prognosis in CRC patients. | — | 58 | | Colorectal liver metastases in 149 patients who underwent radical resection were divided into two groups: those with high HLA-DR expression (above average, n = 75) and those with low HLA-DR expression (below average, n = 74). | The survival rate of patients with high HLA-DR expression was improved, and the level of HLA-DR expression decreased with the increase of the stage of primary cancer. | IFN increased in TME. | 59 | | | OC | Low expression | MAF exhibits a proliferative environment that promotes OC cell growth, and most patients have symptoms of intestinal obstruction. | It may be related to the high expression of TMEMs protein family. | 60 | | High MHC II expression was detected in some patients with recurrent OC in clinical samples (6/12). | It was associated with prolonged OS after Vigil treatment. | — | 61 | | | In end-stage, homologous recombination deficient high-grade serous OC, MHC II expression is lowest in tumors that have acquired genome-wide replication early in tumor evolution. | Patients with low MHC II expression had significantly worse PFS and OS. | Hypermethylation of CIITA pIV is likely to control tsMHC II expression. | 62 | | | PANC | Low expression | Promote immune escape of PANC. | The miR-212-3p secreted by PANC cells can inhibit the expression of RFXAP in DCs, thereby inhibiting MHC II expression. | 63 | | NSCLC | HRD negative NSCLC exhibits MHC II. | HRD positive NSCLC has a poor prognosis and poor response to EGFR-TKIs and immunotherapy. | IFNγ induction | 64 | | High expression in some patients (4/12). | Neoadjuvant ICB combined with chemotherapy had MPR. | IFNγ induction | 65 | | | High expression (≥5% of lung cancer cells express MHC II) | Improved OS | — | 66 | | | Immunotherapy-sensitive cells were tsMHC II positive, while resistant cells were tsMHC II negative. | Expression of tsMHC II positively correlated with anti-PD-1 sensitivity. | Loss and gain of function of CIITA alter the expression of MHC II on cancer cells. | 283 | MHC II, major histocompatibility complex class II molecules; MGBS-II, MHC II genotype binding score; PFS, progression-free survival; OS, overall survival; TMB, tumor mutation burden; PD-1, programmed death 1; ICB, immune checkpoint blockade; HLA, human leukocyte antigen; IFNγ, interferon gamma; CCLE, cancer cell line encyclopedia; PRF1, perforin 1; GZMA, granzyme A; MDM2, murine double minute 2; IL, interleukin; MUP, melanoma of unknown primary; TME, tumor microenvironment; EZH2, enhancer of zeste homolog 2; CIITA, class II major histocompatibility complex transactivator; TNBCs, triple-negative breast cancers; NAC, neoadjuvant chemotherapy; DSP, digital spatial profiler; DFS, disease-free survival; Tregs, regulatory T cells; TDLN, tumor-draining lymph node; ICD, immunogenic cell death; CHL, classic Hodgkin lymphoma; Th, helper T cells; CRC, colorectal cancer; OC, ovarian cancer; MAF, malignant ascites; TMEMs, transmembrane protein family members; CIITA pIV, class II major histocompatibility complex transactivator promoter IV; tsMHC II, tumor-specific MHC II; PANC, pancreatic cancer; DCs, dendritic cells; NSCLC, non-small cell lung cancer; HRD, homologous recombination deficiency; EGFR-TKIs, epidermal growth factor receptor-tyrosine kinase inhibitors; MPR, major pathologic response. Table3: Neoantigen tumor vaccines that increase MHC II expression | Peptide/protein vaccine | LDVax | T3-specific MHC I (G1254V mLama4 plus A506T mAlg8) and MHC II (N710Y mItgb1) SLP | Inhibition of Tr1 cell production and thus selective killing of MHC II tumor antigen-presenting cDC1s | Preclinical trial | MCA sarcoma | 191 | | PancVAX2 | 245 neoantigens identified in the Panc02 cell line | Activation of tumor-specific CD8 + T cells was associated with more proto-immune myeloid suppressor cells and M1-like macrophages in the tumor. | Preclinical trial | PANC cell line Panc02 | 284 | | | IDH1-vac | 20-mer peptide of IDH1 R132H mutant | Inhibiting IDH mutation expression of IDH1 R132H protein, reducing the accumulation of tumor metabolite R-2-HG, and thereby reducing DNA and histone hypermethylation and metabolic reprogramming. | Phase 1 clinical trial | astrocytoma | 285 | | | Double epitope peptide tumor vaccine based on aluminum nanoparticles | MHC I and MHC II peptides are long peptides linked to the double arginine sequence | Simultaneous activation of CD4 + T cells through MHC II peptides can improve the efficiency of MHC I peptides by expanding the strength and duration of the CD8 + T immune response. | Preclinical trial | melanoma | 286 | | | Novel tumor vaccine with NY-SAR-35 antigen | NY-SAR-35 antigen | Induction of IFNγ and IL-4 induces a strong humoral and cell-mediated immune response | Preclinical trial | Breast cancer | 287 | | | CT26 polypeptide vaccine | 7 peptide fragments of CT26 CD8 + T cell epitopes and 4 peptide fragments of CT26 CD4 + T cell epitopes | Bind MHC I and MHC II, TCR and induce IFNγ production | Preclinical trial | CRC | 287 | | | Viral vector vaccine | PeptiCab | MHC I-restricted tumor peptide coated with AdCab (oncolytic adenovirus) | It produces anti-tumor T-effect memory cells that can secrete various inflammatory cytokines. It can polarize neutrophils by upregulating MHC II, CD80, and CD86 to obtain an antigen-presenting phenotype. | Preclinical trial | Melanoma and colon cancer | 200 | | Cellular vaccine | Mel202/DR1/CD80 vaccine | MHC II uveal melanoma cells | Direct activation of multiple purified naive CD4 + T cells. Activated CD4+ T cells proliferate, secrete large amounts of IFNγ, and produce heterogeneous Th1, Th2, and Th17 cytokines | Preclinical trial | uveal melanoma | 288 | Tr1, type 1 regulatory T cell; cDC1s, type 1 conventional dendritic cells; MCA, 3-Methylcholanthrene; IDH1, isocitrate dehydrogenase 1; R-2-HG, (R)-2-hydroxyglutarate; TCR, T cell receptor. Figure legends Figure. 1 Gene and protein structures of MHC II (Created in https://BioRender.com) Figure. 2 Mechanism of APCs process and present antigens through MHC II. Exogenous antigens are recognized and taken up by antigen-presenting cells (APCs), transported from early endosomes to lysosomes, where antigens are degraded into peptides and transported to late endosomes. The Major Histocompatibility Complex Class II molecules (MHC Ⅱ) is synthesized in Endoplasmic Reticulum (ER) and combined with Li chain to form a complex. The Li chain is degraded and the class II-associated invariant chain peptide (CLIP) remains in the antigen-polypeptide binding slot of MHC Ⅱ, and is transported to the late endosome by Golgi apparatus. Under the action of human leukocyte antigen-DM (HLA-DM), the CLIP of the antigen-binding polypeptide binding slot is replaced by the antigen-peptide to be presented. A stable antigenic peptide-MHC II complex is formed and transported from vesicles to the APCs membrane surface, where antigenic peptides are presented to CD4+T cells. CD4 molecules bind to the non-polymorphic region of MHC II as co-receptors, enhancing the affinity between T cell receptors (TCR) and MHC II-antigenic peptide complex. The intracellular portion of the CD4 molecule binds to the lymphocyte-specific protein tyrosine kinase (LCK), which phosphorylates the intracellular regions of the TCR and CD3 molecules, thus initiating signaling. After TCR recognizes the MHC II-antigenic peptide complex, the CD3 molecules in the TCR-CD3 complex (including the γ, δ, ε, and ζ chains) transmit signals to the cell. These signals activate downstream signaling pathways through a series of protein phosphorylation and dephosphorylation events, such as phosphorylated immunoreceptor tyrosine-based activation motif (ITAMs) that provide binding sites for the zeta chain of T cell receptor associated protein kinase 70 (ZAP-70), ultimately leading to T cell activation and proliferation. (Created in https://BioRender.com) Figure. 3 Regulation mechanism of MHC II expression in TME. IFNγ activates the JAK/STAT pathway. pSTAT1 and IRF1 can bind to the CIITA gene promoter. Citrullinated STAT1 promotes its interaction with the inhibitor. The S-X-Y module forms the scaffold for recruiting CIITA. Histone acetylation and DNA methylation promote or inhibit MHC II transcription by altering chromatin structure. Glucose deficiency causes fatty acids, glutamine, leucine, etc. to polarize macrophages towards M2 state through TCA cycle, and can also initiate epigenetic regulation of neutrophil acetyl-coA metabolism. Lactic acid can decrease the expression of MHC II in DCs. Adenosine increases the level of cAMP, which decreases the expression of MHC II in immune cells through the PKA/EPAC pathway. In addition, Adenosine can trigger cAMP/PKA/CREB signaling to inhibit IFNγ and indirectly reduce the expression of MHC II. IFNγ, interferon gamma; IFNγ R1/2, interferon gamma receptor 1/2; JAK, janus kinase; STAT, activator of transcription; ISGs, interferon-stimulated genes; GAS, gamma-activated sequence; IRF1, interferon regulatory factor 1; ISRE, interferon-stimulated response element; RF, regulatory factor ; NF, nuclear factor ; CREB, cAMP response element binding protein; CIITA, class II major histocompatibility complex transactivator; PAD4, peptidylarginine deiminase 4; PIAS1, protein inhibitor of activated STAT1; HAT, histone acetyltransferase; DNMT, DNA methyltransferase; FAO, fatty acid oxidation; CoA, coenzyme A; GLUD, glutamate dehydrogenase; GOT, glutamic-oxaloacetic transaminase; GPT, glutamic-pyruvic transaminase; PSAT, phosphoserine aminotransferase; α-KG, α-ketoglutarate; Adenosine, adenosine; ATP, adenosine triphosphate; AMP, adenosine monophosphate; A2AR, adenosine A2A receptor; PKA, protein kinase A; EPAC, exchange protein activated by cAMP; GPR81, G protein-coupled receptor 81; iNOS, inducible nitric oxide synthase; TLR, toll-like receptor; Ym1/2, chitinase-like proteins Ym1 and Ym2. (Created in https://BioRender.com) Information & Authors Information Version history Peer review timeline Published Critical Reviews in Oncology/Hematology Version of Record1 Oct 2025Published Copyright This work is licensed under a Non Exclusive No Reuse License.

Authors Metrics & Citations Metrics Article Usage 501views 278downloads Citations Download citation Jiaqi Liu, Xueru Song, Wenqi Guo, et al. Unlock the Code of MHC II-enabled Cancer Immunotherapy. Authorea. 25 January 2025. DOI: https://doi.org/10.22541/au.173782765.53711494/v1 DOI: https://doi.org/10.22541/au.173782765.53711494/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu.