CYP19A1 and leiomyoma: The growth of leiomyomas is dependent on estrogen [4] and early studies demonstrated that the expression level of CYP19A1, or aromatase, which is a member of the cytochrome P450 superfamily and converts androgens to estrogens [68], is higher in leiomyomas [101] and this increase is more pronounced in African American women compared with Japanese women [102].