STS and neoplasm: The lattercan be basically divided into steroidal and nonsteroidal derivatives.9,11 Among the steroidal STS inhibitors, EMATE (Figure 1) stood out as themost promising compound, exhibiting a great inhibitory effect withan IC50 value of 65 pM upon evaluation in MCF-7 cells.12 However, in some cases, the presence of thesteroidal core resulted to be associated with the induction of sideeffects that limit clinical use, which include the estrogenic propertiesof metabolites leading to stimulation of tumor growth.