Urinary exosomal AR-V7 as a predictive biomarker for treatment outcomes in castration-resistant prostate cancer

Jingcheng Lyu; Ruiyu Yue; Yukun Liu; Bo Song; Boyu Yang; Fengbo Zhang

doi:10.32604/cju.2026.084989

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Urinary exosomal AR-V7 as a predictive biomarker for treatment outcomes in castration-resistant prostate cancer

Jingcheng Lyu^1,2,#, Ruiyu Yue^3,#, Yukun Liu^3,#, Bo Song^3,*, Boyu Yang^1,2,*, Fengbo Zhang^3,*
1 Department of Urology, Capital Medical University, Beijing Friendship Hospital, Beijing, China
2 Institute of Urology, Beijing Municipal Health Commission, Beijing, China
3 Department of Urology, Capital Medical University, Beijing Luhe Hospital, Beijing, China
* Corresponding Author: Bo Song. Email: email ; Boyu Yang. Email: email ; Fengbo Zhang. Email: email
# Jingcheng Lyu, Ruiyu Yue and Yukun Liu are co-first authors

Canadian Journal of Urology https://doi.org/10.32604/cju.2026.084989

Received 08 May 2026; Accepted 28 August 2026; Published online 17 September 2026

Abstract

Objective: Androgen receptor splice variant 7 (AR-V7) has emerged as a resistance biomarker in castration-resistant prostate cancer (CRPC), yet non-invasive detection methods and its predictive value for first-line treatment selection remain insufficiently characterized. This study investigated the association between urinary exosomal AR-V7 expression and tumor aggressiveness, prognosis, and treatment outcomes in CRPC patients. Methods: This retrospective cohort study enrolled 69 newly diagnosed CRPC patients from two centers (January 2020–January 2026). Urinary exosomes were isolated by ultracentrifugation, and AR-V7 status was determined qualitatively using a TaqMan probe-based qPCR assay (positive: Ct ≤ 35). Survival outcomes were analyzed using multivariable Cox regression and formal interaction testing between AR-V7 status and treatment type (novel hormonal agents [NHA] vs. docetaxel). Results: A total of 28 patients (40.6%) were AR-V7-positive. The AR-V7(+) group exhibited significantly higher tumor risk grades, T stages, M stages, and Gleason scores compared with the AR-V7(−) group (all p < 0.05). Multivariable Cox regression adjusting for treatment type, age, M stage, and Gleason score confirmed AR-V7 positivity as an independent prognostic factor for PFS (adjusted HR = 4.84, 95% CI: 2.23–10.48, p < 0.001) and OS (adjusted HR = 9.34, 95% CI: 3.41–25.64, p < 0.001). A significant treatment-by-biomarker interaction was observed (p < 0.05). In the AR-V7(+) subgroup, NHA was associated with significantly worse outcomes compared with docetaxel (HR for NHA vs. docetaxel: 3.362, 95% CI: 1.476–7.659 for PFS; 9.193, 95% CI: 3.040–27.795 for OS). In the AR-V7(−) subgroup, docetaxel was associated with worse outcomes compared with NHA (HR for NHA vs. docetaxel: 0.458, 95% CI: 0.228–0.918 for PFS; 0.365, 95% CI: 0.144–0.930 for OS). Conclusions: Urinary exosomal AR-V7 is a promising non-invasive candidate predictive biomarker for CRPC treatment stratification. These exploratory findings require validation in larger, multicenter, prospective studies before clinical implementation.