Androgen Receptor Is Expressed in the Majority of Breast Cancer Brain Metastases and Is Subtype-Dependent

• Published in: Cancers Vol. 15; no. 10; p. 2748
• Main Authors: Fan, Kevin Yijun, Chehade, Rania, Qazi, Maleeha, Moravan, Veronika, Nofech-Mozes, Sharon, Jerzak, Katarzyna J
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 13-05-2023; MDPI
• Subjects: Androgen receptors; Androgens; Antibodies; Brain research; Breast cancer; Cancer; Cancer therapies; Care and treatment; Diagnosis; Drug development; ErbB-2 protein; Health aspects; Hormones; Immunohistochemistry; Metastases; Metastasis; Pathology; Patients; Surgery; Therapeutic targets; Tumors; United States > US; breast cancer; brain metastasis; androgen receptor; immunohistochemistry
• ISSN: 2072-6694; 2072-6694
• DOI: 10.3390/cancers15102748

We aimed to evaluate the expression of the "targetable" androgen receptor (AR) in breast cancer brain metastases (BrM). An established, retrospective 57-patient cohort with metastatic breast cancer who underwent surgery for BrM at the Sunnybrook Odette Cancer Centre between 1999-2013 was studied. AR expression in BrM samples was assessed in triplicate using immunohistochemistry (IHC). AR positive status was defined as nuclear AR expression ≥ 10% by IHC using the SP107 antibody. The median age of patients was 52 years (range 32-85 years). 28 (49%) of BrM were HER2+, 17 (30%) were hormone receptor positive (HR+)/HER2-, and 12 (21%) were triple negative breast cancers (TNBCs). 56% (n = 32/57) of BrM were AR positive, and median AR expression was 20% (CI 1.6-38.3%). AR expression was different across breast cancer subtypes; AR was most frequently expressed in HER2+ (n = 21/28), followed by HR+/HER2- (n = 9/17), and lowest in TNBC (n = 2/12) BrM (
= 0.003). Patients with AR positive versus AR negative BrM had similar overall survival (12.5 vs. 7.9 months,
= 0.6), brain-specific progression-free survival (8.0 vs. 5.1 months,
= 0.95), and time from breast cancer diagnosis to BrM diagnosis (51 vs. 29 months,
= 0.16). AR is expressed in the majority of breast cancer BrM and represents a potential therapeutic target.