KRAS and colorectal carcinoma: Recently, Imclone Systems Inc. first developed cetuximab, a recombinant mouse/human chimeric monoclonal antibody that targets the epidermal growth factor receptor (EGFR), to treat patients with EGFR- and wild-type ki-ras2 kirsten rat sarcoma viral oncogene homolog (KRAS)-expressing CRC [5].