Leptin overexpression has been described in multiple types of cancer, such as esophageal cancer, hepatocellular carcinoma, gallbladder cancer, pancreatic cancer, colorectal cancer, renal cell carcinoma, prostate cancer, bladder cancer, breast cancer, endometrial cancer, ovarian cancer, and papillary thyroid cancer [9,10,11]. The gene discussed is LEP; the disease is familial pancreatic carcinoma.