KRAS and cancer: KRAS A146 mutations (A146T, A146V, A146P) disrupt guanine nucleotide binding to promote GDP for GTP exchange39 and are found in MM and a handful of other cancers, including chronic myelogenous leukemia (CML), glioblastoma (GBM), (acute lymphoblastic leukemia (ALL), and acute myeloid leukemia (AML) (Fig. 4A; ref: 1).