The present application discloses 17β hydroxy steroid dehydrogenase (17β HSD) type 1, 3, 10 inhibitors and use thereof (alone and in combination) in the treatment of cancer and other afflictions. 17β HSD1 inhibitors include estradiol derivatives with a nieta-carbamoylbenzyl substituent at C 16. 17β HSD3/HSD10 inhibitors include androsterone derivatives substituted at the C3 position with a sulfonamide piperazine. Also disclosed are compounds that are inhibitors of both 17β HSD1 and 17β HSD3 that have a spiro-morpholine substituent at C20.