Tumor PD-L1 expression is correlated with increased TILs and poor prognosis in penile squamous cell carcinoma

ABSTRACTDespite its rare incidence worldwide, penile squamous cell carcinoma (PeSCC) still presents with significant morbidity and mortality due to the limited treatment options for advanced patients, especially those in developing countries. The program death-1 (PD-1)/PD-1 ligand (PD-L1) axis has been demonstrated to play an important role in tumor immune escape, and immunotherapies targeting this pathway have shown great success in certain cancer types. Here, we analyzed the expression pattern of PD-L1 in tumor cells and tumor-infiltrating lymphocytes (TILs) in PeSCC with a multi-center cohort. We found that the majority of PeSCCs (53.4%) were PD-L1-positive and that high PD-L1 expression in tumor cells was associated with a poor prognosis. Notably, PD-L1 expression in tumor cells was significantly associated with the extent of TILs and CD8+ TILs. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) showed that PD-L1 was positively correlated with interferon-gamma (IFNγ) and CD8+ gene ...