Patients with a colorectal tumor bearing mutated K-ras did not benefit from cetuximab, whereas patients with a tumor bearing wild-type K-ras did benefit from cetuximab. The mutation status of the K-ras gene had no influence on survival among patients treated with best supportive care alone. (ClinicalTrials.gov number, NCT00079066.)

Cetuximab improves overall survival and progression-free survival and preserves quality-of-life measures in patients with colorectal cancer in whom other treatments have failed. (ClinicalTrials.gov number, NCT00079066 [ClinicalTrials.gov].).

ECENT RETROSPECTIVE CORrelative analyses of metastatic colorectal cancer trials indicate that patients with KRAS-mutated tumors (NCBI Entrez Gene 3845) do not benefit from the anti-epidermal growth factor receptor (EGFR) monoclonal antibodies cetuximab and panitumumab. 1 These retrospective analyses were performed independently, and for each analysis, KRAS wild-type vs mutant were studied grouping codons 12 and 13 mutations together, without subgroup analysis. Health authorities in the United States and Europe have indicated that patients with KRAS codon 12-or KRAS codon 13-mutated tumors should not receive cetuximab or panitumumab. 2-4 However, indications exist that not all KRAS mutations are equal in their biological characteristics. First, the pattern of KRAS mutations is tumor-type spe-Author Affiliations are listed at the end of this article.