In contrast, 15.9% of HER2-negative patients exhibited absence of PTEN staining with the highest frequency seen in triple-negative breast cancer (TNBC) subgroup versus ER/PR-positive patients (35.1% vs. 10.9%).
This study was undertaken to determine whether PD-L1 is overexpressed in triple-negative breast cancer (TNBC) and to investigate the loss of PTEN as a mechanism of PD-L1 regulation.