Clinical significance of tumor-associated immune cells in patients with oral squamous cell carcinoma.

BACKGROUND The expression of PD-L1 in tumor cells and infiltration of tumor-associated immune cells (TAICs) might reflect the tumor biology of head and neck cancer. We aimed to characterize their prognostic roles in oral squamous cell carcinomas (OSCCs). METHODS We enrolled 103 OSCC patients who underwent definitive surgery. Immune expression levels of PD-L1, PD-1, CD3, CD4, CD8, and CD68 were assessed in surgically resected specimens. We evaluated the effects of immune marker expression and localization on survival outcomes. RESULTS Multivariate analysis results adjusted by the pathological stage, resection margin, and extracapsular extension showed that a high number of PD-1+ TAICs and intratumoral CD68+ TAICs were independent positive and negative prognostic markers (hazard ratio: 0.20 and 4.15, respectively; P = .02 and .01, respectively). CONCLUSION PD-1+ TAICs in the tumor microenvironment and CD68+ TAICs in the intratumoral area could act as novel biomarkers for predicting overall survival outcomes in OSCC patients.