KRAS and colorectal cancer: It was well-known that KRAS mutations in codons 12 and 13 are established predictive biomarkers for treatment of advanced colorectal cancer, with the antiepidermal growth factor receptor (EGFR) antibodies cetuximab and panitumumab.23, 24KRAS involves mutations in several codons, some of which may show resistance to anti-EGFR treatment.