A novel capillary nano-immunoassay for assessing androgen receptor splice variant 7 in plasma. Correlation with CD133 antigen expression in circulating tumor cells. A pilot study in prostate cancer patients

Purpose Androgen receptor (AR) splice variant 7 (AR-V7) has been related with both a higher risk of prostate cancer (PC) progression and differential responsiveness to hormonal agents versus chemotherapy. The objective of this study was to investigate the feasibility of a novel capillary nano-immunoassay in assessing AR-V7 in plasma from PC patients. Methods Patients with either localized or advanced PC were included in the study. Assessment of AR-V7 in plasma was performed through a capillary nano-immunoassay platform. Correlation with clinical data, stem cell biomarkers (such as CD133+), AR amplification and PTEN status was identified. Results The study included 72 PC patients. AR-V7 signal was detected in 21 (29%) patients: 17 (81%) had a Gleason score ≥7, 15 (71%) castration-resistant prostate cancer (CRPC), 18 (86%) metastatic disease and PSA (median) high than AR-V7 negative ( p