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Updated: Dec 30, 2025
Serum and Plasma Copy Number Detection Using Real-time PCR
Published on: December 15, 2017
AR-V7 Protein Expression in Circulating Tumour Cells Is Not Predictive of Treatment Response in mCRPC
Holger Hans Herman Erb1, Peter Sparwasser2, Tamara Diehl2
1Department of Urology, Technische Universität Dresden, Dresden, Germany.
Introduction:
Androgen receptor variant 7 (AR-V7) plays an important role in the progression of castration-resistant prostate cancer (CRPC) and has shown potential as a predictive biomarker in circulating tumour cells (CTCs) isolated from the bloodstream in terms of a liquid biopsy. Studies have shown that AR-V7 is a potential surrogate for selecting drug classes for systemic treatment by detecting nuclear AR-V7 by immunofluorescence or measuring AR-V7 messenger RNA by quantitative PCR. Here, we assessed the predictive value of AR-V7 detected by classical immunohistochemistry (IHC) for treatment response.
Methods:
CTCs were isolated by cell separation by density gradient centrifugation from patients with metastatic CRPC (n = 26) before, while, and after undergoing a new therapy with chemotherapy (cabazitaxel or docetaxel) or antiandrogen (enzalutamide or abiraterone). CTCs were sequentially cytospun on object slides, and AR-V7 status was then detected by IHC based on a staining regime established on a 22Rv1 cell line with antibodies against CK8/18 und AR-V7.
Results:
AR-V7 status detected by IHC showed no predictive value for progression-free survival (PFS). Kaplan-Meier analysis revealed that there was no difference in PFS between patients found positive or negative for AR-V7.
Discussion/Conclusion:
AR-V7 detected by classical IHC has no predictive value for treatment response in the described setting. The future role of AR-V7 in CTCs as a biomarker in clinical routine remains elusive.
