ESR2 and prostate carcinoma: In addition, a recent study revealed that 17β-HSD6 is expressed in ERβ-positive epithelial cells of the human prostate but that in prostate cancers of Gleason grade higher than 3, both ERβ and 17βHSD6 become undetectable [26], suggesting that formation of 3β-Adiol via 17βHSD6 from DHT could be considered an important growth regulatory pathway, but not a marker of prostate cancer aggressiveness [26].