t(2;3)(p16;q26) BCL11A/MECOM

2013-09-01 Jean-Loup Huret Affiliation

1.Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers, France

Clinics and Pathology

Disease

Phenotype stem cell origin

There were one M1-AML, two M2-AMLs, and one M5-AML; patients presented with dysplasia of at least two myeloid cell lineages.

Epidemiology

Four cases to date; there were three male and one female patients; patients were aged 36, 36, 36, and 55 (in years) (Trubia et al., 2006).

Prognosis

Clinical outcome in cases with the t(2;3)(p16;q26) BCL11A/MECOM and the case with the t(2;3)(p21;q26) THADA/MECOM (plotted together) was severe: "One patient is alive with active disease at 12 months, five patients died after 4-14 months" (Trubia et al., 2006).

Note

MECOM was overexpressed.

Genes Involved and Proteins

Gene name

BCL11A (B-cell lymphoma/leukemia 11A)

Location

2p16.1

Protein description

BCL11A is a Krüppel zinc-finger transcription factor, which has been shown to be essential for pre-B-cell development, thymocyte maturation, and globin switching, expressed in haematopoietic and neural tissues. BCL11A controls FLT3 and IL7R expression in early hematopoietic progenitors (Wu et al., 2013).

Gene name

MECOM (Ecotropic Viral Integration Site 1 (EVI1) and Myelodysplastic Syndrome 1 (MDS1-EVI1)

Location

3q26.2

Note

MECOM is also known as EVI1 or PRDM3; MECOM symbol means: "MDS1 and EVI1 complex locus".

Protein description

"EVI1" contains two domains of seven and three zinc finger motifs, respectively, a repression domain between the two sets of zinc fingers, and an acidic domain at its C-term. Sequence specific DNA binding protein. Interacts with transcriptional coactivators, corepressors, and other sequence specific transcription factors. MECOM ("MDS1-EVI1") also contains a PR domain from "MDS1" in N-term (Wieser, 2008).

Result of the Chromosomal Anomaly

Description

Regulatory elements were transferred at the 5 of MECOM.The t(2;3) brings about the juxtaposition at 3q26 of the MECOM locus with regulatory elements normally located in proximity of the 2p breakpoints, with consequent EVI1 overexpression, without the formation of a fusion protein.

Article Bibliography

Pubmed ID	Last Year	Title	Authors
16619048	2006	Characterization of a recurrent translocation t(2;3)(p15-22;q26) occurring in acute myeloid leukaemia.	Trubia M et al
23741395	2013	Bcl11a controls Flt3 expression in early hematopoietic progenitors and is required for pDC development in vivo.	Wu X et al

Summary

Note

This translocation is found in a subset of cases described in the card t(2;3)(p15-23;q26-27). Other subsets involve other genes, such as THADA in the t(2;3)(p21;q26) THADA/MECOM.

Citation

Jean-Loup Huret

t(2;3)(p16;q26) BCL11A/MECOM

Atlas Genet Cytogenet Oncol Haematol. 2013-09-01

Online version: http://atlasgeneticsoncology.org/haematological/1664/t(2;3)(p16;q26)