Download Leukaemia Section t(8;12)(q24;q22) Atlas of Genetics and Cytogenetics in Oncology and Haematology

Atlas of Genetics and Cytogenetics
in Oncology and Haematology
OPEN ACCESS JOURNAL AT INIST-CNRS
Leukaemia Section
Short Communication
t(8;12)(q24;q22)
Jean-Loup Huret
Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers, France
Published in Atlas Database: October 2007
Online updated version: http://AtlasGeneticsOncology.org/Anomalies/t0812q24q22ID2057.html
DOI: 10.4267/2042/38605
This work is licensed under a Creative Commons Attribution-Non-commercial-No Derivative Works 2.0 France Licence.
© 2008 Atlas of Genetics and Cytogenetics in Oncology and Haematology
Protein
B-cell translocation gene 1 (BTG1) is an antiproliferative gene; it regulates cell growth and
differentiation. BTG1 is strongly expressed in the
G0/G1 phases of the cell cycle, and then downregulated during the G1 phase. Overexpression of
BTG1 results in a retardation of cell proliferation.
Potentially high-affinity self-reactive B cells are
eliminated through the interaction of membrane Ig
(mIg) with self-antigens. Anti-IgM upregulates BTG1
and BTG2, resulting in growth inhibition. Engagement
of mIg on the cells results in G1 arrest and eventual
apoptosis.
Clinics and pathology
Disease
Chronic lymphocytic leukemia (CLL) in blastic
transformation.
Note: CLL was diagnosed after bone marrow recovery
following intensive chemotherapy for acute
lymphoblastic leukemia.
Epidemiology
Only one case to date, 69-year-old female patient.
Cytogenetic
The patient had a primary t(11;14)(q13;q32) in all
lymphocytic/lymphoblastic cells. A subpopulation of
cells carried in addition a t(8;12)(q24;q22) together
with the loss of the normal chromosome 8 and
homozygosity for the abnormal der(8). It is likely that
the t(11;14) corresponded to the CLL, and the subclone
with t(8;12) to the blast population.
References
Archimbaud E, Charrin C, Gentilhomme O, Rimokh R, Guyotat
D, Fiere D, Germain D. Initial clonal acute lymphoblastic
transformation of chronic lymphocytic leukemia with (11;14)
and (8;12) chromosome translocations and acquired
homozygosity. Acta Haematol 1988;79(3):168-73.
Rimokh R, Rouault JP, Wahbi K, Gadoux M, Lafage M,
Archimbaud E, Charrin C, Gentilhomme O, Germain D,
Samarut J, et al. A chromosome 12 coding region is
juxtaposed to the MYC protooncogene locus in a
t(8;12)(q24;q22) translocation in a case of B-cell chronic
lymphocytic leukemia. Genes Chromosomes Cancer 1991
Jan;3(1):24-36.
Prognosis
The patient died 5 months after initial blastic phase.
Genes involved and Proteins
MYC
Iwai K, Hirata K, Ishida T, Takeuchi S, Hirase T, Rikitake Y,
Kojima Y, Inoue N, Kawashima S, Yokoyama M. An antiproliferative gene BTG1 regulates angiogenesis in vitro.
Biochem Biophys Res Commun 2004 Apr 9;316(3):628-35.
Location: 8q24
Protein
Transcription factor binding to specific DNA
sequences, upon dimerization to Max (Max can also
form heterodimers with Mad as well as homodimers
with itself). Myc/Max complexes activate transcription
and promote cell proliferation and transformation.
Mad/Max complexes, repress transcription.
Hata K, Nishijima K, Mizuguchi J. Role for Btg1 and Btg2 in
growth arrest of WEHI-231 cells through arginine methylation
following membrane immunoglobulin engagement. Exp Cell
Res 2007 Jul 1;313(11):2356-66.
This article should be referenced as such:
Huret JL. t(8;12)(q24;q22). Atlas Genet Cytogenet Oncol
Haematol.2008;12(6):455.
BTG1
Location: 12q22
Atlas Genet Cytogenet Oncol Haematol. 2008;12(6)
455