MLL insertion with MLL-MLLT3 gene fusion in acute leukemia: case report and review of the literature.

A new chromosomal insertion involving the MLL gene was detected by fluorescence in situ hybridization in a patient with acute myeloblastic leukemia (AML) and a t(9;11)(p21;q13). Genomic polymerase chain reaction confirmed the MLL-MLLT3 gene fusion. A review of the literature on MLL insertions shows that the opposite orientation of the genes involved in the fusion plays a role in the genesis of the rearrangement in most of the cases reported.