MLL-SEPTIN gene fusions in hematological malignancies

Abstract

AbstractThe mixed lineage leukemia (MLL) locus is involved in more than 60 different rearrangements with a remarkably diverse group of fusion partners in approximately 10% of human leukemias.MLLrearrangements include chromosomal translocations, gene internal duplications, chromosome 11q deletions or inversions andMLLgene insertions into other chromosomes, or vice versa. MLL fusion partners can be classified into four distinct categories: nuclear proteins, cytoplasmatic proteins, histone acetyltransferases and septins. Five different septin genes (SEPT2,SEPT5,SEPT6,SEPT9, andSEPT11) have been identified asMLLfusion partners, giving rise to chimeric fusion proteins in which the N terminus of MLL is fused, in frame, to almost the entire open reading frame of the septin partner gene. The rearranged alleles result from heterogeneous breaks in distinct introns of bothMLLand its septin fusion partner, originating distinct gene fusion variants.MLL-SEPTIN rearrangements have been repeatedly identified inde novoand therapy related myeloid neoplasia in both children and adults, and some clinicopathogenetic associations are being uncovered. The fundamental roles of septins in cytokinesis, membrane remodeling and compartmentalization can provide some clues on how abnormalities in the septin cytoskeleton and MLL deregulation could be involved in the pathogenesis of hematological malignancies.