Prognostic value and clinicopathological status of PD‐L1 expression and CD8+ TILs in oral squamous cell cancer patients with or without traditional risk factors

Abstract

AbstractBackgroundNon‐smokers, non‐drinkers, and non‐betel quid chewers (NSNDNBs) with oral squamous cell carcinoma (OSCC) have poor survival outcomes. Tumor microenvironment based on PD‐L1/CD8+ T cell infiltrated lymphocyte (TIL) proportion is proposed as a prognostic indicator.MethodsImmunohistochemistry staining was performed on OSCC samples from 64 patients. The PD‐L1/CD8+ TILs were scored and stratified into four groups. Disease‐free survival (DFS) was analyzed using a Cox regression model.ResultsOSCC in NSNDNB patients was associated with female sex, T1‐2 classification, and PD‐L1 positivity. Low CD8+ TILs correlated with perineural invasion. High CD8+ TILs correlated with improved DFS. PD‐L1 positivity was not correlated with DFS. Type IV tumor microenvironment yielded the highest DFS (85%).ConclusionNSNDNB status relates to PD‐L1 expression regardless of CD8+ TILs infiltration. Type IV tumor microenvironment was associated with the best DFS. High CD8+ TILs resulted in better survival, while PD‐L1 positivity alone was not correlated to DFS.