Association of PD-L1 expression in oral squamous cell carcinoma with smoking, sex, and p53 expression

Objectives. The aim of this study was to investigate the association between oral cavity squamous cell carcinoma (OSCC) and PD-L1 expression, and smoking, and p53 expression. Study Design. Histologic review of archival slides of patients with OSCC, obtained from the Sydney Head and Neck Cancer Institute database from 1995 to 2015, was undertaken with tissue microarray construction and immunohistochemistry to identify PD-L1 and p53 expression. Results. Of the 255 patients identified, PD-L1 expression was observed in 70 (27.5%) and more commonly in females (odds ratio [OR]= 2.19; P=.005). PD-L1 expression of 1% or greater was associated with p53 expression (P=.019) and associated with absence of smoking (P=.06). PD-L1 expression, at 1%, was not significantly associated with overall survival (P=.482), disease-specific survival (P=.864), and disease-free survival (P=.731). Conclusions. Our data demonstrate that PD-L1 expression of 1% or greater is more frequent in OSCC in females, nonsmokers, and in patients with p53-positive OSCC. These findings have important implications for immune therapy for OSCC.