Terminal deoxynucleotidyl transferase promotes acute myeloid leukemia by priming FLT3-ITD replication slippage.

FLT3-internal tandem duplications (FLT3-ITDs) are prognostic driver mutations found in acute myeloid leukemia (AML). Although these short duplications occur in 25% of AML patients, little is known about the molecular mechanism underlying their formation. Understanding the origin of FLT3-ITDs would advance our understanding of the genesis of AML.

Molecular roulette: nucleophosmin mutations in AML are orchestrated through N-nucleotide addition by TdT.

Nucleophosmin (NPM1) is the most commonly mutated gene in acute myeloid leukemia (AML). AML with mutated NPM1 is recognized as a separate entity in the World Health Organization 2016 classification and carries a relatively favorable prognosis. NPM1 mutations are predominantly 4-bp duplications or insertions in the terminal exon that arise through an unknown mechanism.

Constitutional and somatic rearrangement of chromosome 21 in acute lymphoblastic leukaemia.

Changes in gene dosage are a major driver of cancer, known to be caused by a finite, but increasingly well annotated, repertoire of mutational mechanisms. This can potentially generate correlated copy-number alterations across hundreds of linked genes, as exemplified by the 2% of childhood acute lymphoblastic leukaemia (ALL) with recurrent amplification of megabase regions of chromosome 21 (iAMP21). We used genomic, cytogenetic and transcriptional analysis, coupled with novel bioinformatic approaches, to reconstruct the evolution of iAMP21 ALL.

NUP98-NSD1 fusion in association with FLT3-ITD mutation identifies a prognostically relevant subgroup of pediatric acute myeloid leukemia patients suitable for monitoring by real time quantitative PCR.

The cytogenetically cryptic t(5;11)(q35;p15) leading to the NUP98-NSD1 fusion is a rare but recurrent gene rearrangement recently reported to identify a group of young AML patients with poor prognosis. We used reverse transcription polymerase chain reaction (PCR) to screen retrospectively diagnostic samples from 54 unselected pediatric AML patients and designed a real time quantitative PCR assay to track individual patient response to treatment. Four positive cases (7%) were identified; three arising de novo and one therapy related AML.

The histone acetyl transferase activity of monocytic leukemia zinc finger is critical for the proliferation of hematopoietic precursors.

The monocytic leukemia zinc finger (MOZ) gene encodes a large multidomain protein that contains, besides other domains, 2 coactivation domains for the transcription factor Runx1/acute myeloid leukemia 1 and a histone acetyl transferase (HAT) catalytic domain. Recent studies have demonstrated the critical requirement for the complete MOZ protein in hematopoietic stem cell development and maintenance. However, the specific function of the HAT activity of MOZ remains unknown, as it has been shown that MOZ HAT activity is not required either for its role as Runx1 coactivator or for the leukemic transformation induced by MOZ transcriptional intermediary factor 2 (TIF2).

Identification of an angiogenic factor that when mutated causes susceptibility to Klippel-Trenaunay syndrome.

Angiogenic factors are critical to the initiation of angiogenesis and maintenance of the vascular network. Here we use human genetics as an approach to identify an angiogenic factor, VG5Q, and further define two genetic defects of VG5Q in patients with the vascular disease Klippel-Trenaunay syndrome (KTS). One mutation is chromosomal translocation t(5;11), which increases VG5Q transcription.

A murine model of CML blast crisis induced by cooperation between BCR/ABL and NUP98/HOXA9.

Constitutive activation of tyrosine kinases, such as the BCR/ABL fusion associated with t(9;22)(q34;q22), is a hallmark of chronic myeloid leukemia (CML) syndromes in humans. Expression of BCR/ABL is both necessary and sufficient to cause a chronic myeloproliferative syndrome in murine bone marrow transplantation models, and absolutely depends on kinase activity. Progression of CML to acute leukemia (blast crisis) in humans has been associated with acquisition of secondary chromosomal translocations, including the t(7;11)(p15;p15) resulting in the NUP98/HOXA9 fusion protein.