Clinicopathological and prognostic significance of programmed death ligand 1 expression in Korean patients with triple-negative breast carcinoma

Background/Aim: The clinicopathological and prognostic significances of programmed death ligand 1 (PDL1) expression in triple-negative breast carcinoma (TNBC) are still unclear. We investigated whether PD-L1 expression is associated with clinicopathological characteristics and outcomes of TNBC patients. Materials and Methods: We performed immunostaining for PD-L1 (SP142) in 83 TNBCs. Staining proportion of =1% was regarded as positive PD-L1 expression. Results: Positive intratumoral (IT) PD-L1 expression (19/83; 22.9%) was inversely associated with lymphovascular invasion (LVI) and distant metastasis, and was significantly associated with better disease-free survival for TNBC patients. Positive stromal PD-L1 expression (44/83; 53.0%) also correlated inversely with LVI. Conclusion: Positive IT PD-L1 expression was associated with favorable outcomes in TNBC. In addition, positive IT and stromal PD-L1 were inversely associated with LVI and distant metastasis of TNBC.