Beyond Exon 2-The Developing Story of RAS Mutations in Colorectal Cancer

Initial single-agent studies of anti-epidermal growth factor receptor (anti-EGFR) antibodies in the treatment of colorectal cancer showed that these agents were marginally effective.(1),(2) The minority of patients derived benefit, as evidenced by progression-free survival curves that had no inflection until well after the 50% mark. However, after the determination that activating mutations in exon 2 of the gene KRAS predicted the inefficacy of anti-EGFR antibodies, reanalyses of multiple trials suggested that these agents could be more effective when administered to a more limited cohort of patients.(3) Thus, mutations in exon 2 of KRAS became the first biomarkers of colorectal ...