[Correlation of VISTA and PD-L1 expression with the clinicopathological features and prognosis in triple-negative...

Objective: To investigate the expression of VISTA and PD-L1 in triple-negative breast cancer (TNBC) and to explore its relationship with clinicopathologic features and prognosis. Methods: Ninety TNBC patients who underwent surgical resections between 2016 to 2018 in Jiangsu Province Hospital were selected. The expression of VISTA and PD-L1 in both tumor cells and immune cells was evaluated by immunohistochemistry, and the relationship with clinicopathologic parameters and prognosis was analyzed. Results: VISTA was expressed in 17.8% (16/90) of the tumors. The expression of VISTA in tumor cells was related to a higher Ki-67 proliferation index (P=0.02) and higher number of tumor-infiltrating lymphocytes (TIL, P<0.01). VISTA was expressed in 71.1% (64/90) of the immune cells and the expression correlated with smaller tumor size (P=0.02), lower T stage (P=0.04), higher number of TIL (P<0.01), higher number of CD8⁺T cells (P=0.03) and higher Ki-67 proliferation index (P=0.02). PD-L1 was expressed in 17.8% (16/90) of the immune cells and the expression correlated with higher histologic grade (P=0.04), higher Ki-67 proliferation index (P=0.02) and higher number of TIL (P<0.01). VISTA expression was higher in immune cells within TNBC patients than PD-L1 (P<0.01). Among 90 TNBC patients, complete follow-up was obtained in 85 patients, 8 of whom had recurrences or metastasis after surgery, and two patients cases died of recurrences or metastasis. Conclusions: The expression rate of VISTA is higher than that of PD-L1 in TNBC. The expression of VISTA in immune cells predicts a lower T stage. VISTA may act as an effective immunotherapy target.