Assessing the utility of aromatase cytochrome P450 mRNA (CYP19) quantity as a diagnostic tool for endometriosis and adenomyosis, Hatok et al. (2011) observed a statistically significant increase (p = 0.0002) in CYP19 expression in eutopic endometrial biopsy specimens from women with adenomyosis (56%), endometriosis (73.3%), or both diseases (65.5%) compared to disease-free women (21.7%) (Hatok et al., 2011). The gene discussed is CYP19A1; the disease is endometriosis.