EGFR and colorectal carcinoma: Tyrosine kinase inhibitors such as gefitinib (EGFR inhibitor) desensitises CRC cells to the antitumour effect of the drugs by promoting the heterodimerisation of EGFR and IGF1Rβ, leading to cross-regulation of the IGFR1β and MAPK signalling pathways (Yang et al., 2011).