FLT3 and acute lymphoblastic leukemia: Mutations in RAS pathway proteins (e.g., KRAS, NRAS, FLT3, PTPN11, and NF1) are highly prevalent in acute lymphoblastic leukemia (ALL), with such mutations occurring in 40%–50% of pediatric B cell ALL cases (Irving et al., 2014; Jerchel et al., 2018; Oshima et al., 2016; Zhang et al., 2011).