Although triple-negative breast cancers, which lack expression of ERα, PR, and HER2, are more frequently diagnosed in premenopausal patients [18], the impact of obesity on the risk of development of triple-negative breast cancer in premenopausal women is less clearly defined [19,20,21], which may be in part due to underlying familial risk factors that impact younger women. The gene discussed is ESR1; the disease is obesity due to melanocortin 4 receptor deficiency.