Finally, HER2-positive breast cancer may well benefit from immunotherapeutic interventions with anti-programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1) agents.
Some of this resistance has been attributed to the upregulation of immune checkpoints such as programmed cell death-1 (PD-1) and its ligand, PD-L1 in Her2-positive breast cancer patients.
In this review, we discuss the current evidence for PD-1/PD-L1 blockade in metastatic triple-negative breast cancer (TNBC), HER2+ breast cancer and ER+ disease, as well as the emerging evidence for use in the early-stage (neoadjuvant) setting.
In addition, we demonstrate for the first time that high PD-L1 expression is also associated with better outcome in ER- disease as a whole including HER2+ breast cancer.
Evaluation of Immune Reaction and PD-L1 Expression Using Multiplex Immunohistochemistry in HER2-Positive Breast Cancer: The Association With Response to Anti-HER2 Neoadjuvant Therapy.
Therefore, our data suggest cytotoxic immune reaction mediated by CD8-positive T cells and PD-L1 expression may predict a better outcome in patients with HER2-positive breast carcinoma managed with conventional chemotherapy and HER2-blocking therapy.