GH1 and cancer: Substantial experimental evidence supports the involvement of growth hormone (GH) and, especially, its main effector insulin-like growth factor-I (IGF-I) in the development, growth, and dissemination of several types of cancer (Cianfarani and Rossi, 1997; Holly et al., 1999, Renehan et al., 2004; Clayton et al., 2011).