Infiltration of PD-1-positive cells in combination with tumor site PD-L1 expression is a positive prognostic factor in cutaneous angiosarcoma

ABSTRACTCutaneous angiosarcoma(CAS) is a malignant sarcoma with poor prognosis. Programmed cell death-1 (PD-1)/ programmed cell death-1 ligand-1 ( PD-L1) expression reflects antitumor immunity, and is associated with patient prognosis in various cancers. The purpose of this study is to investigate the relationship between PD-1/ PD-L1expression and CAS prognosis. CAS cases (n = 106) were immunohistochemically studied for PD-L1and PD-1 expression, and the correlation with patient prognosis was analyzed. PD-L1expression was assessed by flow cytometry on three CAS cell lines with or without IFNγ stimulation. A total of 30.2% of patients' samples were positive for PD-L1, and 17.9% showed a high infiltration of PD-1-positive cells. Univariate analysisshowed a significant relationship between a high infiltration of PD-1-positive cells with tumor site PD-L1expression and favorable survival in stage 1 patients (p = 0.014, log-rank test). Multivariable Cox-proportional hazard regression analysis also showed that...