LNPEP as a Prognostic-Related Biomarker in Ovarian Cancer Correlating with Immune Infiltrates

Background: Leucyl And Cystinyl Aminopeptidase (LNPEP) encodes a zinc-dependent aminopeptidase, which has been proved to participate in the vesicle-mediated transport and class I major histocompatibility complex-mediated antigen processing and presentation. However, the function of LNPEP in the tumor immune microenvironment of ovarian cancer (OV) and its potential molecular mechanisms have not been elucidated. Material: and Methods To analyze the expression profile, prognostic value, and immune infiltration of LNPEP, bioinformatics web resources, including Gene Expression Profiling Interactive Analysis Gent2, HPA, Cbioportal, Kaplan–Meier Plotter, and tumor immune estimation resource, were employed. The related genes of LNPEP in OV were mined by TISIDB and LinkedOmics database. The protein-protein interaction network involving LNPEP was constructed by GeneMANIA and STRING database. Additionally, further studies of pathway and LNPEP expression were conducted through GSEA. The protein levels of LNPEP were validated by western-blot assay and immunohistochemistry. Results: The mRNA expression of LNPEP was noticeably down-regulated in OV than its expression in para-cancer tissues, contrary to the protein level. Importantly, high LNPEP expression was associated with poor prognosis in patients with OV. Furthermore, Cox regression analysis showed that LNPEP was an independent prognostic factor in OV. From the GO and KEGG pathway analyses, it was observed that the co-expressed genes of LNPEP were mainly related to a variety of immune-related pathways, including Th1 and Th2 cell differentiation, Th17 cell differentiation, and immunoregulatory interaction between a lymphoid and a non-lymphoid cell. Our data also demonstrated that LNPEP expression was strongly correlated with immune infiltration rates, immunomodulators, chemokine, and chemokine receptors. Conclusions: We identified and established a prognostic signature of immune-related LNPEP in OV, which will be important for predicting the prognosis of clinical trials and may become a new therapeutic target for immunological research and potential prognostic biomarker in OV.