CYP19A1 and benign prostatic hyperplasia: In addition to the conversion of testosterone to DHT, there is an increased conversion of androgen to estrogen (catalyzed by aromatase) in aging men, and the released estrogens cause increased expression of DHT and stimulation of the prostatic stroma, resulting in prostate proliferation and BPH (Eleazu et al., 2016a; Zhou et al., 2010; Kumar et al., 2010).