Mutations of the transcription factor PU.1 are not associated with acute lymphoblastic leukaemia

The transcription factor PU.I plays a crucial role during normal haematopoiesis in both myeloid cells and B-lymphocytes. Mice with a disruption in both alleles of the PU.I locus were found to lack macrophages and B cells and had delayed appearance of neutrophils. In addition, critical decrease of PU.I expression is sufficient to cause acute myeloid leukaemia (AML) and lymphomas in mice. Recently, we reported that heterozygous mutations in the PU.I gene are present in some patients with AML. Thus, we hypothesised that PU.I mutations might also contribute to the development of acute leukaemias of the B-cell lineage. Here, we screened 62 patients with B-cell acute lymphoblastic leukaemia (B-ALL) at diagnosis for genomic mutations by direct sequencing of all five exons of the PU.I gene. We found no genomic alteration of the PU.I gene suggesting that PU.I mutations are not likely to be common in B-ALL.