Potent bicyclic nonsteroidal sulfamate-based active-site-directed inhibitors of the enzyme steroid sulfatase (STS), an emerging target in the treatment of post-menopausal hormone-dependent diseases, including breast cancer, were designed.179 The compounds were examined for STS inhibition in intact MCF-7 breast cancer cells and in placental microsomes. This evidence concerns the gene STS and breast carcinoma.