Abnormal expression of B2M inhibits immune evasion of head and neck cancers through the PDL1 axis

PURPOSE Head and neck cancers exhibit immune dysregulation closely linked to immune escape, which may occur in response to immunosuppressive cells, immune checkpoints, antigen loss, and immune escape ligands. However, the specific mechanism of immune escape is not known yet. This study aimed to investigate the immune escape mechanism through molecular and genetic verification experiments. PATIENTS AND METHODS The head and neck cancer data were downloaded from the TCGA database. Similarly, head and neck tumor samples were collected from 40 patients and subjected to qPCR and immunohistochemical analysis to verify the roles of B2M, PDL1, CD8, and PRF1 in head and neck tumors. RESULTS The analysis of TCGA data revealed a correlation between B2M and HLA (R = 0.722, P < 0.5), whereas the correlation between B2M and CD8A, PDL1, and PRF1 was found to be R = 0.525, P < 0.5, R = 0.534, P < 0.5, and R = 577, P < 0.5, respectively. Similarly, the qPCR analysis revealed that B2M, CD8A, PDL1, and PRF1 expression levels were significantly higher in laryngeal squamous cell carcinoma (LSCC) tumors than in adjacent tissues. B2M was variably expressed in different clinical stages of LSCC, where an increased positive expression of B2M was observed at higher stages, while the CD8A, PDL1, and PRF1 expressions were relatively low. Analysis of survival curves of different LSCC clinical stages showed that the higher clinical stage was associated with shorter survival, which was associated with higher B2M expression. These results are suggestive of B2M affecting head and neck cancers. CONCLUSION Immune evasion of head and neck tumors may result from imbalanced MHCI complexes, which interact with CD 8+ T cells and secrete PRF1, resulting in immune cell infiltration and tumor growth.