Prognostic significance of PD-L1 and PD-L2 in breast cancer

Hum Pathol. 2016 Jan;47(1):78-84. doi: 10.1016/j.humpath.2015.09.006. Epub 2015 Sep 25.


PD-L1 and PD-L2 constitute an important antitumor immune response. In breast cancer, their prognostic value is still to be defined. In this study, we investigate the correlation between PD-L1 and PD-L2 protein expressions with clinical and pathologic features and disease-free survival and overall survival. To assess PD-L1 and PD-L2 expressions, we conducted immunohistochemistry studies using a breast cancer tissue microarray encompassing a total of 192 breast cancer cases, stages I, II, and III, with detailed clinical and outcome data. PD-L1 expression was present in 56.6% (107/189), and PD-L2 expression was identified in 50.8% (97/191) of breast cancer cases. Younger age at diagnosis, lymph node positivity, negative estrogen receptor, and recurrence at distant sites were all associated with both PD-L1 and PD-L2 expressions. The presence of larger tumors was associated only with PD-L1 expression. In our study, PD-L1 expression was significantly associated with better overall survival (P = .04) in breast cancer patients. Despite its association with poor clinical and pathologic features, PD-L1 expression emerges as a positive prognostic biomarker in breast cancer. This survival result might be due to the presence of a strong antitumor immune response leading to PD-L1 expression.

Keywords: Biomarker; Breast cancer; PD-L1; PD-L2; Prognosis; Survival.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • B7-H1 Antigen / analysis*
  • Biomarkers, Tumor / analysis*
  • Breast Neoplasms / chemistry*
  • Breast Neoplasms / immunology
  • Breast Neoplasms / mortality
  • Breast Neoplasms / pathology
  • Breast Neoplasms / therapy
  • Disease-Free Survival
  • Female
  • Humans
  • Immunohistochemistry
  • Kaplan-Meier Estimate
  • Lymphatic Metastasis
  • Middle Aged
  • Neoplasm Staging
  • Programmed Cell Death 1 Ligand 2 Protein / analysis*
  • Receptors, Estrogen / analysis
  • Risk Factors
  • Time Factors
  • Tissue Array Analysis
  • Tumor Burden


  • B7-H1 Antigen
  • Biomarkers, Tumor
  • CD274 protein, human
  • PDCD1LG2 protein, human
  • Programmed Cell Death 1 Ligand 2 Protein
  • Receptors, Estrogen