As an example, aromatase inhibitors – which suppress estrogen serum levels and are currently approved as a treatment of (hormone-receptor positive) breast cancer in premenopausal (in addition to a GnrRH analog) and postmenopausal women and in men and gynecomastia in men [154] – might theoretically be an attractive treatment option in men with chronic migraine. This evidence concerns the gene CYP19A1 and breast carcinoma.