CMTM6 and PD-1/PD-L1 overexpression is associated with the clinical characteristics of malignancy in oral squamous cell carcinoma.

Objectives: This study aimed to evaluate the expression of chemokine-like factor superfamily 6 (CMTM6) and programmed cell death 1 (PD-1)/programmed death ligand 1 (PD-L1) in oral squamous cell carcinoma (OSCC) and to further explore its clinical significance in OSCC.
Study Design: Samples of 44 OSCC and paracancerous tissues were investigated. We estimated the expression of the 3 proteins by immunohistochemistry and further detected mRNA expression by quantitative real-time polymerase chain reaction (qRT-PCR).
Results: Immunohistochemistry results demonstrated that the positive expression of CMTM6 and PD-1/PD-L1 in OSCC tissues was significantly higher than that in paracancerous tissues. Statistical significance was found between the 2 groups (all P < .05). Moreover, PD-L1 expression was related to OSCC clinical stage and lymph node metastasis (P < .05). The qRT-PCR results confirmed that the relative expression of CMTM6 and PD-1/PD-L1 mRNA in OSCC tissues was significantly higher than that in paracancerous tissues (all P < .05), and Spearman rank correlation showed that there was a significant relationship between mRNA and protein expression (all P < .05).
Conclusions: CMTM6 and PD-1/PD-L1 were upregulated in OSCC, and CMTM6 may play a synergistic role with PD-1/PD-L1 in the immune pathway. Therefore, we believe that CMTM6 and PD-1/PD-L1 will become checkpoints for immunotherapy of OSCC.
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