CRLF2 and acute lymphoblastic leukemia: Thus, patients with Ph-like ALL cases are divided into two major classes for therapeutic targeting purposes: ABL class (including ABL1, ABL2, CSF1R, and PDGFRB rearrangements) and JAK pathway activating (including CRLF2, JAK2, or EPOR rearrangements, SH2B3 deletions, and IL7R indels) (Figure 1A).