LEP and breast cancer: Black women, with or without BC, had significantly higher serum leptin levels (median [IQR], 55.3 [40.3-66.2] ng/mL and 29.1 [21.1-46.5] ng/mL, respectively, P < .001) than White women (median [IQR], 33.4 [18.9-47.7] ng/mL and 16.5 [10.0-22.9] ng/mL, respectively), which was associated with higher odds of luminal A disease (OR, 5.25; 95% CI, 1.69-14.32, P = .003).