HSD17B2

17β-HSD2 is involved in inactivation of androgens and estrogens,^[8] being accurately describable as "antiandrogenic" and "antiestrogenic",^[9] and is the key 17β-HSD isozyme in androgen and estrogen inactivation.^{[8][additional citation(s) needed]} Specific reactions catalyzed by 17β-HSD2 include estradiol to estrone, testosterone to androstenedione, and androstenediol to DHEATooltip dehydroepiandrosterone.^[8][10] In addition to 17β-HSD activity, this enzyme also shows high 20α-hydroxysteroid dehydrogenase activity and can activate the weak progestogen 20α-hydroxyprogesterone into the potent progestogen progesterone.^[8][10]

17β-HSD2 is widely expressed throughout the body including in the placenta, liver, intestines, endometrium, kidney, pancreas, breast, prostate, bone, and many other tissues.^[11][12]

Polymorphisms in HSD17B2 have been associated with breast cancer and prostate cancer.^[13] 17β-HSD2 activity has also been associated with endometriosis and osteoporosis,^[14] and inhibitors of the enzyme are of potential interest in the treatment of the latter condition.^[15][16] Inactivating mutations resulting in a syndrome of congenital deficiency of 17β-HSD2 have not been reported to date.^[17]