CRLF2 and acute lymphoblastic leukemia: The age distribution was similar to B‐ALL overall, with the majority <10 years (71%).20 Median age (4 y vs. 14 y, P < .001), WBC (25% vs. 43% with WBC >50 × 106/l, P = .016) and percentage NCI high risk (38% vs. 77%, P < .001) differed significantly between P2RY8‐CRLF2 and IGH‐CRLF2, respectively (Supporting Information Table 4; Figure 1A).