High weight gain was associated with two-fold increased risks of BC overall (OR = 2.71, 95% CI:1.29-5.69, Ptrend = 0.01) and ER+PR+ BC (OR = 2.47, 95% CI:1.03-5.94, Ptrend = 0.03) only in women who had experienced menopause ≥15 years ago. The gene discussed is ESR1; the disease is breast cancer.