Although studies have shown that the status of KRAS and NRAS is independent of the tumor staging [37, 43], since Lievre et al. [44] first reported that the mutations of KRAS can reduce the efficacy of anti-EGFR mAbs in 2006, emerging studies have confirmed that RAS mutations are the major causes of resistance to anti-EGFR therapy [5, 43, 45–50]. Here, KRAS is linked to neoplasm.