New E2A/PBX1 fusion transcript in a patient with t(1;19)(q23;p13) acute lymphoblastic leukemia

About 25% of the children with pre-B cell acute lymphoblastic leukemia (ALL) have a chromosomal translocation of t(1;19)(q23;p13). This translocation juxtaposes the E2A gene on chromosome 19 to the PBX1 gene on chromosome 1, leading to production of a fusion transcript. The fusion sites of the E2A and PBX1 coding sequence have been identical among all cases of t(1;19) ALL studied so far. Here we described a new fusion site of the E2A and PBX1 genes, which was detected in the leukemic blasts of a child with t(1;19) pre-B ALL using the reverse transcriptase polymerase chain reaction and direct sequencing. The fusion site was located just upstream of the DNA binding domain of the E2A gene, and was close to a homeodomain of the PBX1 gene.