Pd-L1 Expression in Oral Cavity Squamous Cell Carcinomas.

Programmed cell death ligand-1 (PD-L1) is involved in T-cell regulation by acting as an immune checkpoint inhibitor, and its expression is being widely studied in various malignancies. The following study was designed to examine the role of PD-L1 and its association with HPV in oral squamous cell carcinomas in the Indian population. Immunohistochemistry for PD-L1 and p16 was done on the resection specimens. Combined positive score (CPS) was evaluated for PD-L1; a CPS  1and < 20 was considered low-positive, and a CPS  20 was considered strong positive. Diffuse and strong nuclear and cytoplasmic expression of p16 in  70% tumor cells was considered positive (block) expression. A total of 188 cases were included in the study. PD-L1 expression was seen in a total of 86.1% (162 cases); of these, 67.02% (126 cases) showed strong expression of PD-L1 with a CPS  20. A significant correlation was observed between PD-L1 expression and tumor stage, with higher PD-L1 expression in advanced stages T2-4 compared to T1 (p-value = 0.014). No significant correlation of PD-L1 with p16 positivity, lymph node metastases, or tumor grade was observed. High PD-L1 expression was observed in more than 80% of cases, regardless of HPV status, suggesting that targeted immunotherapy with PD-L1 inhibitors can be an effective treatment in the Indian subpopulation, especially in those with advanced-stage tumors.