PAX5-KIAA1549L: a novel fusion gene in a case of pediatric B-cell precursor acute lymphoblastic leukemia.

In B-cell precursor acute lymphoblastic leukemia (BCP-ALL) PAX5, a transcription factor pivotal for B-cell commitment and maintenance, is frequently affected by genetic alterations. In 2-3 % of the cases PAX5 rearrangements result in the expression of oncogenic fusion genes. The encoded chimeric proteins consist of the N-terminal PAX5 DNA-binding paired domain, which is fused to the C-terminal domains of a remarkable heterogeneous group of partner proteins. Employing fluorescence in situ hybridization and molecular methods PAX5-KIAA1549L was identified as novel fusion gene in a case of pediatric BCP-ALL. Our report underlines the high diversity of PAX5 fusion partners in BCP-ALL and we describe the second involvement of KIAA1549L in a genetic rearrangement in acute leukemia.