Because HSP90B1 is a dominant isoform in the HSP90 family and is critically involved in disease development [23,24], we investigated its protein expression profile by proteomic analysis using ovarian tissues from 10 patients with PCOS, and we defined the role of HSP90B1 in the pathogenesis of PCOS. This evidence concerns the gene HSP90AB1 and polycystic ovary syndrome.