Tumor-produced high molecular weight insulin-like growth factor (IGF)-II (big IGF-II) is considered to cause hypoglycemia, and big IGF-II production by various tumors, such as hepatocellular carcinoma, gastric cancer, mesothelioma, hemangiopericytoma, leiomyosarcoma, and fibrous tumor, has been previously reported [2]. This evidence concerns the gene IGF2 and leiomyosarcoma.