Thirteen of these patients (27%) were classified as BCR-ABL1-like based on heatmap clustering, with all equally showing overexpression of ENAM and IGJ. Also, most of the patients with high CRLF2 expression (CRLF2+) were classified into the BCR-ABL1-like ALL subgroup: 11/13 (85%) versus 7/36 (19%) non-BCR-ABL1-like, P < 0.001. This evidence concerns the gene CRLF2 and acute lymphoblastic leukemia.