KRAS and cancer: The proto-oncogene KRAS is among the most frequentlymutated genes in human cancers, with mutations found in approximately14% of patient samples.1 Its protein product(KRas) is a membrane-localized small GTPase responsible for cell growthand proliferation signaling through its effectors RAF and PI3K.2 Transforming mutations in KRAS (most commonly at G12, G13, or Q61) result in an increased cellularproportion of active GTP-bound KRas, typically by impairing the hydrolysisreaction of GTP.