Patient is a 63-year-old female with a past medical history significant for stage IV invasive ductal carcinoma, positive for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), with osseous metastases to the calvarium and ribs, heart failure with preserved ejection fraction, diabetes mellitus type 2, hypertension, obstructive sleep apnea, unspecified anxiety disorder, and recurrent major depressive disorder. The gene discussed is ESR1; the disease is diabetes mellitus.