KRAS is a member of the RAS protein family, a group of small GTPases involved in cell signaling pathways that regulate cell growth, proliferation, differentiation, and survival. KRAS functions as a molecular switch by cycling between an inactive GDP-bound state and an active GTP-bound state. Activation of KRAS triggers downstream signaling pathways that promote normal cellular functions. Mutations in KRAS, such as the Q61R mutation, impair its GTPase activity and lock the protein in the active GTP-bound form, resulting in continuous signaling that drives uncontrolled cell proliferation and cancer development. KRAS mutations are frequently found in pancreatic, colorectal, and lung cancers. The KRAS Q61R nucleotide exchange assay is a TR-FRET–based assay designed to measure GTP binding activity and evaluate inhibitors targeting KRAS Q61R-mediated signaling pathways.