CYP19A1 and breast cancer: 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).