Nevertheless, secondary mutations in the extracellular domain of EGFR, mutations in KRAS, NRAS and C-Met, loss of PTEN and activating mutations in PIK3CA, and gain-of-activity in the IGFR pathway have been associated with acquired resistances of some cases of colorectal cancer (8, 9, 126, 127). Here, EGFR is linked to colorectal cancer.