FKBP5 and prostate cancer: Considering the link between HSPs and AR activity, we next investigated the impact of NXP800 on AR signaling, demonstrating a decrease in AR-FL and AR-V7 protein expression, and also in expression of AR-responsive genes (KLK2, KLK3, TMPRSS2, and FKBP5), across all three prostate cancer cell lines (Fig. 2A–C).