ERBB2 and obesity due to melanocortin 4 receptor deficiency: Besides well-known prognostic factors such as age, stage of disease, HER2-Neu expression, and estrogen and progesterone receptor status, factors relating to the cancer patient’s metabolism such as obesity [3, 4], sarcopenia [5, 6], insulin levels [7, 8], and chronic hyperglycemia [9–11] have been shown to possess a prognostic role.