RUNX1 and acute lymphoblastic leukemia: The majority, including those with DS‐ALL, were classified as B‐other ALL (Figure 1B,C); however, primary, established chromosomal abnormalities co‐occurred in 22% (Supporting Information Table 1): ETV6‐RUNX1 (n = 3), BCR‐ABL1 (n = 5), high hyperdiploidy (n = 12), and iAMP21 (n = 17).