Breast cancer tissue has STS, 3βHSD, reductive 17βHSD, 5α-reductase and aromatase activities (Labrie et al., 2003, McNamara and Sasano, 2015b, Suzuki et al., 2005) as well as 3αHSD, UGT, and SULT activity (McNamara et al., 2013). Here, CYP19A1 is linked to breast carcinoma.