EBF1 and chronic myelogenous leukemia, BCR-ABL1 positive: Deletion of IKZF1 (IKAROS), CDKN2A, PAX5 and EBF1 genes are common features of BCR-ABL+ lymphoid leukemia (CML at its progression to lymphoid blast crisis) but are rarely present in CML in its chronic phase9–11.