Association of Androgen Receptor Expression on Tumor Cells and PD-L1 Expression in Muscle-Invasive and Metastatic Urothelial Carcinoma: Insights for Clinical Research

BACKGROUND: Limited information is available regarding the use of androgen receptor (AR) immunohistochemical expression in muscle-invasive or metastatic urothelial carcinoma. We aimed to evaluate the frequency of AR expression by tumor cells (TC), its prognostic role, and its relationship with programmed cell-death ligand 1 (PD-L1) expression in these patients.

PATIENTS AND METHODS: From September 2015 to January 2017, we collected tissue from patients who received platinum-based chemotherapy at our center. Immunohistochemistry for AR was performed (1% cutoff of TC). PD-L1 coexpression, by TC or immune cells (1% cutoff), was also analyzed. Molecular analysis of AR gene was performed by sequencing of exons 5 to 8 and by fluorescence in-situ hybridization analysis. Cox models for overall survival (OS), adjusted for stage, visceral metastases, and platinum type, were fitted.

RESULTS: A total of 110 patients had tumor samples stained. Overall, 48 (43.6%) had AR-expressing TC: 19 (17.3%) had 1%-5% expression, 15 (13.6%) 5%-25% expression, and 14 (12.7%) > 25% expression. Among the latter, 7 had molecularly evaluated tumor tissue: no AR gene mutations or amplifications were found, but polysomy of Xq chromosome was seen. PD-L1 expression by TC and immunohistochemistry concordantly decreased with increasing levels of AR expression by TC. In Cox analyses, AR expression was not associated with OS, both on univariable (P = .477) and multivariable (P = .505) analyses.

CONCLUSION: AR is frequently expressed in patients with muscle-invasive and advanced urothelial carcinoma, and it does not seem to be prognostic for OS. The AR pathway is worthy of clinical studies to assess its synergistic action with anti-PD-L1 therapy.