KRAS and rectal cancer: In this study, we describe the frequency of missense mutations and copy number variation (CNV) of wild-type (wt) and mutated alleles of KRAS and NRAS in a very large dataset of 13,336 CRC tumors from patients profiled by Foundation Medicine (FM) Inc. We separately report results based on occurrence in MSS versus MSI-H tumors, in colon versus rectal cancer, and based on patient age.