Stromal PD-L1 Expression Is Associated With Better Disease-Free Survival in Triple-Negative Breast Cancer.
OBJECTIVE
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.
From the Department of Pathology and Laboratory Medicine, xli40@emory.edu.
Xiaoxian
X
Li
Department of Biology, Georgia State University, Atlanta.
Ceyda Sonmez
CS
Wetherilt
From the Department of Pathology and Laboratory Medicine.
Uma
U
Krishnamurti
Department of Biostatistics.
Jing
J
Yang
Morehouse College, Atlanta, GA.
Yamin
Y
Ma
Department of Surgery, and.
Toncred M
TM
Styblo
Department of Hematology and Medical Oncology, Emory University, Atlanta, GA.
Jane L
JL
Meisel
Department of Biostatistics.
Limin
L
Peng
From the Department of Pathology and Laboratory Medicine.
Momin T
MT
Siddiqui
From the Department of Pathology and Laboratory Medicine.
Cynthia
C
Cohen
Department of Biology, Georgia State University, Atlanta.
Ritu
R
Aneja
D060890:B7-H1 Antigen / Q000378:metabolism*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000473:pathology*; D060787:Neoplasm Grading; D011379:Prognosis; D061026:Programmed Cell Death 1 Receptor / Q000378:metabolism*; D017154:Stromal Cells / Q000378:metabolism* / Q000473:pathology; D015996:Survival Rate; D064726:Triple Negative Breast Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology
D060890:B7-H1 Antigen; C423236:CD274 protein, human; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor
Breast cancer; Disease-free survival; Full-face section; Overall survival; PD-1; PD-L1; Stromal PD-L1 expression; TNBC