Colon cancer patients with KRAS mutations do not respond to cetuximab or panitumumab, which are antibodies that target epidermal growth factor receptor (EGFR).2–5 Because these mutations are found in 40% of colon cancers,6 additional treatment options and biomarkers of response are urgently needed for KRAS mutant cancers. The gene discussed is KRAS; the disease is colonic neoplasm.