TGFA and cancer: EGFR’s 2 cognate ligands, EGF and transforming growth factor alpha (TGFα), after receptor binding, activate multiple downstream signaling pathways, including the mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K)/AKT, protein kinase C (PKC) and Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathways, which increase cancer cell proliferation, pro-survival functions and apoptotic resistance5 (Figure 1).