SFRP1 and posterior cortical atrophy: Hence, we performed a cell viability test to investigate the potential effect of SFRP1 on PCa cells that did not express AR or TMPRSS2-ERG but SFRP1 and how was expected, not effect was observe in PC3 (AR negative) and RWPE-1 (non-cancerous epithelial cells (Fig. 3e, f).