KRAS and metastatic colorectal cancer: In the study by Lièvre et al.,6 the relative risk of responding to cetuximab was 10-fold higher for the patients who had metastatic colorectal cancer without KRAS mutations than for those with KRAS mutations (HR, 10.5; 95 % confidence interval [CI], 2.1–51.1). The authors concluded that a prospective randomized study was needed for validation.