AR and posterior cortical atrophy: Importantly, applying an interruption approach for blocking the AR function during the co-culture system showed that infiltrating HMC-1 cells no longer were able to significantly increase the CD133+ stem/progenitor cell population in PCa C4-2 cells (Figure 5D), suggesting infiltrating HMC-1 cells might function through down-regulation of AR to increase PCa CD133+ stem/progenitor cell population.