PD-L1 expression in breast cancer: expression in subtypes and prognostic significance: a systematic review

To systematically review the literature on the expression of PD-L1 in primary BC, variation of expression between subtypes and effect on overall survival (OS), disease-free survival (DFS), and recurrence-free survival (RFS). Additionally, for studies in the neoadjuvant setting, we have reviewed the ability of PD-L1 to predict pathological complete response (pCR). Articles included in this review were retrieved by searching PubMed (1966–2018) and...