SOS1 and chronic myelogenous leukemia, BCR-ABL1 positive: Importantly, in the analysis of mice cohorts of the appropriate genotypes and controls grown under similar conditions in parallel, SOS1 appeared to be significantly more relevant than SOS2 regarding CML development since SOS1 ablation resulted in about a ~4-month increase in CML survival and a 40% increase in lifespan compared to the WT controls (Figure 2A) in comparison with the ~2-month increase in survival shown by the SOS2-KO mice (Figure 2C).