It acts by hydrolyzing inactive steroid sulfates[including estrone-3-sulfate (E1S) and dehydroepiandrosterone-3-sulfate(DHEAS)],6,7 which are the precursors for the biosynthesisof active estrogens and androgens.8 Recentevidence prompted STS as an extremely important new molecular targetin the development of novel and effective cancer therapies.9 STS inhibition may also be of relevance in thetreatment of other hormone-dependent types of tumors, for example,endometrial and prostate cancers.10 This evidence concerns the gene STS and cancer.