Stromal PD-L1 Expression Is Associated With Better Disease-Free Survival in Triple-Negative Breast Cancer

Am J Clin Pathol. 2016 Oct;146(4):496-502. doi: 10.1093/ajcp/aqw134.


Objectives: Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer, and there is no approved targeted therapy. We studied the expression of programmed cell death protein 1 (PD-1) and its ligand (PD-L1) in TNBC.

Methods: Full-face sections from 136 TNBC cases without neoadjuvant therapy between 2004 and 2013 were stained and evaluated for immune cell PD-1 staining and stromal or tumoral PD-L1 staining using the H-score (staining percentage × intensity). Nottingham histologic grade, lymphovascular invasion (LVI), mitotic count, and tumor-infiltrating lymphocytes (TILs) were evaluated. Tumor size, lymph node status, Ki-67 score, metastasis, overall survival (OS), and disease-free survival (DFS) were retrieved from medical records.

Results: Of the 136 TNBC cases, 69 (51%) had any PD-L1 staining and 35 (26%) had PD-L1 staining with an H-score of 5 or more; 117 (86%) had any PD-1 staining and 68 (50%) had PD-1 staining with an H-score of 5 or more. Tumor size and LVI were significantly associated with worse OS and DFS, and TILs and LVI were significantly associated with metastasis in univariate analysis. Stromal PD-L1 expression was significantly associated with better DFS in multivariate analysis. PD-1 expression was not associated with DFS, OS, or metastasis.

Conclusions: PD-L1 expression is seen in a high proportion of TNBCs and associated with better DFS.

Keywords: Breast cancer; Disease-free survival; Full-face section; Overall survival; PD-1; PD-L1; Stromal PD-L1 expression; TNBC.

MeSH terms

  • B7-H1 Antigen / metabolism*
  • Disease-Free Survival
  • Female
  • Humans
  • Lymphatic Metastasis / pathology*
  • Neoplasm Grading
  • Prognosis
  • Programmed Cell Death 1 Receptor / metabolism*
  • Stromal Cells / metabolism*
  • Stromal Cells / pathology
  • Survival Rate
  • Triple Negative Breast Neoplasms / metabolism*
  • Triple Negative Breast Neoplasms / mortality
  • Triple Negative Breast Neoplasms / pathology


  • B7-H1 Antigen
  • CD274 protein, human
  • PDCD1 protein, human
  • Programmed Cell Death 1 Receptor