LEP and breast cancer: To observe whether leptin, being a bioactive signaling molecule, could mediate the risk association of BMI with early-onset BC and luminal A and TNBC diagnosis, we prospectively enrolled 99 patients with BC (53 Black and 46 White) along with 100 controls without BC (50 each from self-reported Black and White racial groups) (eTable 2 in Supplement 1).