Although IGF1 has been proposed as a tumor-promoting factor due to its established oncogenic effects exerted through its receptor (IGF1R) in vitro and in engineered mouse models [59,60], a substantial number of published evidences [61] point at IGF-II as the insulin-like growth factor used by most cancers and produced by malignant cancer cells in vivo. The gene discussed is IGF1; the disease is cancer.