SFRP1 and prostate cancer: To study whether sFRP1 could affect AR transcriptional activity, we expressed sFRP1 in 22Rv1 cells, an AR-positive prostate cancer cell line that does not express sFRP family members (data not shown), together with the androgen-responsive reporter MMTV-luciferase and a control reporter, and treated cells with the AR ligand dihydrotestosterone (DHT).