IGF1 and cancer: Several studies have suggested that the insulin‐like growth factor‐1 receptor (IGF‐1R) pathway is an essential target of EBV‐positive cancer such as NPC.17 IGF‐related ligands (IGF‐1, IGF‐2 and insulin) and insulin‐like growth factor binding proteins (IGFBPs) are produced the liver that are stimulated by growth hormone (GH).