CRLF2 and acute lymphoblastic leukemia: After the exclusion of two patients with KMT2A gene rearrangements identified by RNA-Seq, remaining cases without canonical B-ALL gene fusions and cases with high hyperdiploidy or low hypodiploidy (n = 101) were selected for RNA-Seq and CRLF2 gene break FISH analysis to identify other kinase and cytokine receptor activating lesions (Fig. 1).