EGFR and colorectal cancer: K-RAS mutations in colorectal cancers have been clinically shown to render tumors insensitive to the EGFR-directed antibodies cetuximab and panitumumab, whereas the EGFR-directed small molecule erlotinib has obtained FDA approval for the treatment of pancreatic cancer, of which over 70–90% possess K-RAS mutations [4], [40].