AR and benign prostatic hyperplasia: In addition, mRNA levels of HSP90 isoforms and AR-FL were significantly upregulated in metastatic CRPC compared to normal prostate or benign prostatic hyperplasia and primary PCa in two independent GEO microarray datasets (Figure 7A and Figure S12A), and AR-FL expression was significantly correlated with levels of HSP90 isoforms (Figure 7B).