Positive PD-L1 Expression Predicts Worse Outcome in Cutaneous Angiosarcoma

PURPOSE: Programmed death-1 (PD-1) or programmed death ligand-1 (PD-L1) targeted therapies have shown promising survival outcomes in several human neoplasms. However, it is unclear whether the expression of PD-L1 can be correlated to any clinical and pathologic variables in patients with cutaneous angiosarcoma (CA). The aim of this study was to evaluate the clinicopathological significance of PD-L1 expression in CA patients. MATERIALS AND METHODS: Data from 52 patients with CA were retrospectively reviewed. PD-L1 expression, tumor proliferation determined by Ki-67 index, and immunohistochemical evaluation of tumor-infiltrating lymphocytes, CD4+ and CD8+, were used to determine correlation with clinicopathological variables. RESULTS: PD-L1 was positively expressed in 40% of all patients. PD-L1 expression was significantly associated with tumor cell proliferation. Multivariate analysis confirmed that high levels of CD8+ tumor-infiltrating lymphocytes were a significant predictor in patients with clinical stage I CA and the positive expression of PD-L1 was an independent prognostic factor in predicting worse outcome. CONCLUSION: PD-L1 expression is a novel pathologic marker for predicting worse outcome in patients with CA.