Variant of ETV6/ABL1 gene is associated with leukemia phenotype.

The ETV6/ABL1 fusion transcript is thought to be a very rare aberration in hematopoietic malignancies. We describe two new cases of acute leukemia with the ETV6/ABL1 fusion, acute myeloid leukemia with eosinophilia (case 1) and B acute lymphoblastic leukemia (ALL) (case 2), screened by multiplex RT-PCR. The ETV6/ABL1 fusion was also confirmed by fluorescence in situ hybridization using a mixture of BCR/ABL1 and ETV6/RUNX1 probes. A thorough review of all published cases showed that all 7 reported ALL patients possess the type A ETV6/ABL1 fusion transcript, composed of the first 4 exons of ETV6 fused to the second exon of ABL1. The presence of the type A fusion transcript strongly implies ALL manifestation in ETV6/ABL1-positive hematologic malignancies as minor BCR breakpoint in BCR/ABL1-positive ALL.