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. (Oral Surg Oral Med Oral Pathol Oral Radiol 2021;132:202-209)

Automated summary

The study showed that the expression of CMTM6 and PD-1/PD-L1 was significantly higher in OSCC tissues compared to paracancerous tissues. PD-L1 expression was associated with clinical stage and lymph node metastasis in OSCC. qRT-PCR results confirmed the relationship between mRNA and protein expression.