CYP19A1 and breast cancer: Our previous study demonstrated that, in stages I-II and operable stage III breast cancer patients, hormone receptor- (HR-) positive premenopausal patients with the long allele of the CYP19 polymorphism have a significantly better DFS and OS than those without the long allele, but this prognostic effect of the CYP19 polymorphism is not seen in postmenopausal women patients [8].