IGF1 and lung cancer: In lung cancer, TGFβ is one of the most important physiologic EMT inducers, along with other factors such as HGF, FGF (Fibroblast Growth Factor), IGF (Insulin-like Growth factor-1)/PDGF, EGF/VEGF, each secreted by the tumor or/and its microenvironment and acting through downstream pathways including Wnt/β-catenin, TGFβ/SMAD, Notch, MAPK/ERK, and PI3K/Akt [27,28].