KRAS and acute lymphoblastic leukemia: For example, in MLL-rearranged infant ALL in whom NRAS/KRAS mutations are present in 24–50% of cases, mutations were shown to be an independent prognostic factor associated with an extremely poor outcome, with a 5-year event free survival rates of 0.0% for RAS mutated compared to 32.7% for RAS wildtype (47, 75).