IGF1 and cancer: The insulin-like growth factor (IGF) axis consisting of the heterotetrameric IGF-1 receptor (IGF-1R) and its high affinity binding ligands IGF-1 and IGF-2 have been implicated in all stages of cancer growth and progression including cellular transformation, epithelial-to-mesenchymal transition (EMT), invasion and metastasis, as well as in the regulation of the tumor microenvironment1–5.