ESR1 and breast cancer: In African American women participating in the AMBER (African American Breast Cancer Epidemiology and Risk) Consortium, historical obesity (defined as young adult weight) was associated with a decreased risk of ER-positive breast cancer, but not overall or ER-negative breast cancer, whereas recent BMI was not significantly linked with pre-menopausal ER-positive, ER-negative, or triple-negative diseases [47].