An association between endocrine symptoms plus breast density, if confirmed, may have important clinical implications given that estrogen receptor-positive breast cancer incidence is rising31, particularly among younger women who are generally not eligible to take aromatase inhibitors unless they are at high-risk of recurrence, and in which situation, ovarian suppression or oophorectomy might be clinically indicated32,33. Here, CYP19A1 is linked to breast carcinoma.