The Expression of PDL-1 and PD1 in the Microenvironment of Oral Squamous Cell Carcinoma

Objective: Immune checkpoint proteins, especially PD-1/PD-L1, play a vital role in controlling the intensity and duration of the immune response. However, cancer cells often over-expression PDL-1 on their surfaces, which leads to the permanent activation of the PD-1/PDL-1 pathway and exhaustion of T cells and creates a resistant tumor microenvironment. This study aimed to analyze PD-1, PD-L1 expression in tumor cells (PDL-1/TC) and in Tumor-Infiltrating Lymphocytes (PDL-1/TILS) of OSCC patients and associated with and to correlate it with histologic grade of malignancy and clinicopathologic parameters. Methods: The sample consisted of 43 archived specimens of 43 patients of OSCC with Clinical features (gender, age, smoking, clinical stage) collected from medical records between 2014-2021. The intensity of PD-1, PDL-1/TC, PDL-1/TILS, positive cells were assessed by immunohistochemistry. Result: PDL-1/TILS and PDL-1/TC were observed in all specimens except two cases in well-differentiated were negative. PDL-1/TILS was significant between histological grades(P=0.004<0.05). There was no significant between PDL-1/TC and PDL-1/TILS and between poorly differentiated and moderately differentiated groups’ ROC P values (P=0.133, 0.340>0.05) respectively. There is a difference between PDL-1/TC and PDL-1/TILS between poorly differentiated and well-differentiated groups ROC P value (0.005, 0.028), Sensitivity (0.857, 0.857), specificity (0.765, 0.824) respectively and there is a difference between and PDL-1/TILS moderate differentiated and well-differentiated groups ROC P value (0.133,) Sensitivity (0.737), specificity (0.765). No differences between PDL-1/TC and moderate and well-differentiated groups P value (0.173). There is a significant correlation between PDL-1/TC and PDL-1/TILS with an age P>65 value (0.032) in the well-differentiated group. PDL-1/TC and PDL-1/TILS with the depth of invasion (DOI) in the well-differentiated group. No significant correlation was obtained between PDL-1/TC and PDL-1/TILS and smoking, clinical stage, and gender. No significant correlation was obtained between PD1 and the histological grades or clinicopathologic characteristics. Conclusion: PDL-1/TILS and PDL-1/TC are independent prognostic factors in OSCC and PDL1-/TILS has an important role.