PD-1/PD-L1 Pathway in Breast Cancer

Oncol Res Treat. 2017;40(5):294-297. doi: 10.1159/000464353. Epub 2017 Mar 27.


The programmed cell death-1 receptor (PD-1) is an immune checkpoint inhibitor which is expressed on the surface of immune effector cells. It is activated mainly by PD-L1 which can be expressed by all human cells. The PD-1/PD-L1 pathway plays a subtle role in maintaining peripheral T-lymphocyte tolerance and regulating inflammation. In cancer, the expression of PD-L1 seems to be one of the major immune escape mechanisms. Many studies have shown efficacy of blocking PD-1 or PD-L1 with specific antibodies like pembrolizumab or atezulizumab. In breast cancer, potential response was demonstrated in metastatic triple-negative breast cancers.

Keywords: Breast cancer; Immune checkpoints; Immunotherapy; PD1/PD-L1.

Publication types

  • Review

MeSH terms

  • Animals
  • Antibodies, Monoclonal / immunology
  • Antibodies, Monoclonal / therapeutic use*
  • Antineoplastic Agents / immunology
  • Antineoplastic Agents / therapeutic use
  • B7-H1 Antigen / immunology*
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / immunology*
  • Breast Neoplasms / pathology
  • Cell Survival / drug effects
  • Cell Survival / immunology
  • Female
  • Humans
  • Metabolic Networks and Pathways / drug effects
  • Metabolic Networks and Pathways / immunology*
  • Molecular Targeted Therapy / methods
  • Programmed Cell Death 1 Receptor / immunology*
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / immunology*
  • Treatment Outcome


  • Antibodies, Monoclonal
  • Antineoplastic Agents
  • B7-H1 Antigen
  • CD274 protein, human
  • PDCD1 protein, human
  • Programmed Cell Death 1 Receptor