RTKs that have been found to activate these pathways independent from EGFR activation in CRC that can confer resistance to cetuximab include ERBB2/HER2, mesenchymal–epithelial transition factor (MET) receptor, and insulin-like growth factor receptor (IGF-1R) [134,135,136,137,138,139,140]. The gene discussed is ERBB2; the disease is colorectal carcinoma.