ERBB2 and cancer: Data clearly demonstrate that when patients with cancer develop acute or chronic kidney disease, severe fluid and electrolyte abnormalities, outcomes are inferior, and the promise of curative therapeutic regimens is lessened. We present a case of a 74-year-old woman with metastatic, recurrent ER+/PR-/HER2+ invasive ductal carcinoma of the right breast, status post bilateral mastectomies, chemotherapy, radiation therapy, and hormonal therapies, who were clinically stable on Trastuzumab/Pertuzumab maintenance for about a year.