[Evaluation of PD-L1 expression and intratumoral lymphocytic infiltration in triple-negative invasive breast carcinoma].

Introduction: Triple negative breast cancer endophenotype (TNBC) is one of the least frequent and without therapeutic target; therefore we propose to study the correlation of PD-L1 immune checkpoint with the establishment of tumor microenvironment assessed by intratumoral stromal lymphocyte infiltration (TILS) and its importance in clinical practice.

Methods: A retrospective case-control study was performed, with 31 cases of triple-negative infiltrating breast carcinoma and 57 unmatched controls of Luminal A, Luminal B and HER-2 endophenotype seen in one year. The following variables were evaluated: histologic type and grade, PD-L1 expression with clone 22C3, TILS, lymphovascular invasion, tumor size, lymph node involvement and metastasis.