INS and cancer: Inhibition of RTKs with small-molecule inhibitors and monoclonal antibodies (mAbs) is conventional therapy in various cancers.5 Activation of RTKs with various ligands (replacement therapy), such as insulin and growth factors (GFs), is used to treat diabetes,2 neurodegeneration,6 wound healing and muscle regeneration.7 While insulin as a hormone acts on multiple organs and tissues,2 the activity of other RTK ligands is usually localized and their use for therapeutic purposes should be spatio-temporally controlled.