KRAS and neoplasm: KRAS mutations were found to vary significantly by tumor side (P < .0001), with 46.3% (95% CI: 42.3%‐50.4%) of right‐sided colon cancers harboring a KRAS mutation compared to 35.8% (95% CI: 32.2%‐39.6%) of left‐sided tumors (Figure 2A,B).