Abstract
Background:Triple-negative breast cancers comprise 15% of breast cancers and are more common in women with BRCA1 mutations. Although most have basal gene expression signatures, others resemble luminal tumors with expression of androgen receptor-related genes and some express the immunoinhibitory protein programmed death-ligand 1 (PD-L1). Given the availability of androgen receptor-targeted and immune therapies for triple-negative breast cancers, determining predictors of these biomarkers is important.Aims:To determine the prevalence and predictors of androgen receptor and PD-L1 expression in BRCA1-associated and sporadic triple-negative breast cancer.Methods:We studied 197 triple-negative breast cancers: 78 (39.6%) from BRCA1 mutation carriers and 119 (60.4%) from noncarriers. Tumor pathology was reviewed and tissue microarray sections were immunostained for androgen receptor and PD-L1.Results:Androgen receptor expression was seen in 18% of tumors and was significantly less common in tumors from BRCA1 mutation carriers than noncarriers (9.2 vs. 23.7%; P=0.01). Twenty-six percent of cancers expressed PD-L1 with no significant difference in frequency between carriers and noncarriers. Factors predicting androgen receptor expression were lower histologic grade (odds ratio (OR) 4.6; 95% confidence interval (CI) 1.1–19.7), older age at diagnosis (OR 1.3; 95% CI 1.03–1.7) and PD-L1 expression (OR 2.6; 95% CI 1.1–6.1). PD-L1 expression was significantly more common in cancers with lymphocytic infiltrates (OR, 3.3; 95% CI 1.1–10.4) and androgen receptor expression (OR, 3.2; 95% CI 1.4–7.5), and less common in tumors with lymphovascular invasion (OR 0.41; 95% CI 0.18–0.92).Conclusions:These results identify predictors for androgen receptor and PD-L1 expression among triple-negative breast cancers that may lead to better treatment selection and participation in clinical trials.
Highlights
Triple-negative breast cancer (TNBC) comprises 15% of all breast cancers and is characterized by the absence of expression of estrogen receptor (ER), progesterone receptor (PR), and the human epidermal growth factor receptor 2 (HER2)
BRCA1 mutation carriers were significantly younger at diagnosis than noncarriers
There was no difference in axillary nodal involvement between triple-negative breast cancer (TNBC) in BRCA1 mutation carriers and noncarriers (Table 1)
Summary
Triple-negative breast cancer (TNBC) comprises 15% of all breast cancers and is characterized by the absence of expression of estrogen receptor (ER), progesterone receptor (PR), and the human epidermal growth factor receptor 2 (HER2). There was no significant difference in PD-L1 cancer cell expression between TNBC from BRCA1 carriers and noncarriers (22.7% vs 28.8%; P = 0.35). When PD-L1 positivity on cancer or inflammatory cells is considered, of the 177 TNBC evaluable, 163 (92.1%) were PD-L1+ with no significant difference in frequency between BRCA1-associated and sporadic TNBC (P = 0.11: Table 2).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
