JAK2 and acute myeloid leukemia: When classified by tumor type, the majority of variants in B-ALL were in KRAS, NOTCH1, PAX5, CREBBP, PTPN11, and JAK2. In AML, the most common mutations identified were in NRAS, RUNX1, and FLT3. ETV6-RUNX1 was the most common fusion identified in 6.7% (9/134) panels from patients with B-ALL (Figs. 2 and 5).