Programmed death-ligand 1 (PD-L1) expression predicts response to neoadjuvant chemotherapy in triple-negative breast cancer: a systematic review and meta-analysis.

Background: In patients with metastatic triple-negative breast cancer (TNBC), programmed death-ligand 1 (PD-L1) expression has been demonstrated to predict response to immunotherapy. It is unclear whether PD-L1 expression measured with currently available validated assays can predict chemotherapy response in patients with non-metastatic TNBC.

Methods: We conducted a systematic review and meta-analysis of clinical studies to assess the PD-L1 expression as a predictor of response to chemotherapy in non-metastatic TNBC using validated assays.