IGF1R and cancer: IGF1-R is a transmembrane protein that contains two extracellular α subunits with the ligand-binding site and two transmembrane β subunits with intracellular tyrosine kinase activity.6, 8 It is activated by engagement with IGF1 and IGF2 and has an important physiological role in regulating cell growth and proliferation that has been established in knockout mice.6, 8, 11, 12 Although upregulation of IGF1-R has been found in many types of cancers including colon cancer,8 the mechanism(s) of the increase remains elusive.