Objective: The RUNX1 (also known as AML1) gene is observed frequently as the target of chromosomal rearrangements in human acute leukemia. We describe here a previously unreported rearrangement, t(11;21)(q13;q22), that disrupts the RUNX1 gene in a patient with acute leukemia and the molecular analysis of the fusion gene.
Methods: We have established a monocytic leukemia cell line, ELAM-1, from a patient with acute leukemia evolving from myelodysplastic syndrome (MDS). Translocation (11;21) (q13;q22) was observed in both patient leukemia cells and ELAM-1.
Results: The split signal of RUNX1 was detected by fluorescence in situ hybridization and indicated the involvement of RUNX1 in ELAM-1. Using 3'- Rapid amplification of cDNA ends and reverse transcription-Polymerase chain reaction analysis, we detected both RUNX1 (exon 5)-LRP16 and RUNX1 (exon 6)-LRP16 transcripts, suggesting that the RUNX1 breakpoint lies in intron 6 and that alternative fusion splice variants are generated. Reciprocal LRP16-RUNX1 fusion was also detected.
Conclusions: We identified a novel RUNX1 fusion partner, LRP16 on 11q13 involving t(11;21)(q13;q22). Although it was reported that overexpression of LRP16 promotes human breast cancer cell proliferation, the function of LRP16 in leukemia remains to be studied. This fusion gene and cell line may provide a new research tool to investigate the mechanism of leukemogenesis generated by the RUNX1 fusion gene.