t(3;7)(q26;q21) MECOM/CDK6

2005-08-01   Clelia Tiziana Storlazzi , Francesco Albano 

1.Department of Genetics, Microbiology, University of Bari, Via Amendola 165/A, 70126 Bari, Italy

Clinics and Pathology

Noted

This translocation has been observed in myeloid leukemia [one case of acute myeloid leukemia (AML), subtype M4, and two cases of chronic myeloid leukemia in blast crisis (CML-BC)]

Disease

blast crisis chronic myelogenous leukemia (myeloid-myeloid/NK phenotype)

Phenotype stem cell origin

myeloid leukemia

Prognosis

poor

Disease

AML M4

Phenotype stem cell origin

Acute myeloid leukemia

Prognosis

poor

Cytogenetics

Cytogenetics morphological

t(3;7)(q26;q21) in BC-CML; -7,+der(7)t(3;7)(q26;q21) in AML M4
Atlas Image
FISH cohybridization between clones identifying breakpoints on chromosome 3 (RP11-33A1) and 7 (RP11-332M5) in a case of BC-CML with a t(3;7)(q21;q26).

Additional anomalies

Sole anomaly in AML; Ph chromosome in BC-CML patients

Variants

No variants described.

Genes Involved and Proteins

Gene name
MECOM (Ecotropic Viral Integration Site 1 (EVI1) and Myelodysplastic Syndrome 1 (MDS1-EVI1)
Location
3q26.2
Note
EVI1 is expressed at very low levels in normal peripheral blood and bone marrow. The gene is overexpressed in myeloid leukemias and myelodysplastic syndromes as a result of chromosomal rearrangements at either the 5 region of the gene in t(3;3)(q21;q26) or at the 3 region in inv(3)(q21q26) by juxtaposition of the gene to putative enhancer elements of the Ribophorin I gene in 3q21. High expression of EVI1 can also occur in the t(3;21)(q26;q22) as part of the fusion gene AML1/MDS1/EVI1 in CML-BC, or MDS or as part of the fusion gene ETV6/MDS1/EVI1 in AML with t(3;12) translocation. EVI1 is also involved in other translocations such as t(2;3)(p13;q26), t(2;3)(q23;q26), t(3;17)(q26;q22) and t(3;13)(q26;q13-14). Other studies have reported abnormal expression of EVI1 in MDS and AML without 3q26 structural abnormalities, suggesting that inappropriate activation of this gene occurs through various mechanisms.
Dna rna description
16 exons spanning 64.2 Kb. Transcriptional orientation is from telomere to centromere. 6 splicing variants.
Protein description
1051 amino acids; 118335 Da. Nuclear location, contains 10 C2H2-type zinc fingers.
Gene name
CDK6 (cyclin dependent kinase 6)
Location
7q21.2
Dna rna description
7 exons spanning 229 Kb. Transcriptional orientation is from telomere to centromere.
Protein description
326 amino acids; 36938 Da. It belongs to the Ser/Thr protein kinase family, CDC2/CDKX subfamily. It is probably involved in the control of the cell cycle. Interacts with D-type G1 cyclins.

Result of the Chromosomal Anomaly

Note

overexpression of EVI1 in bone marrow; no detected CDK6/EVI1 fusion gene in any of the myeloid leukemia cases analyzed.

Bibliography

Pubmed IDLast YearTitleAuthors
153227642004Myeloid/natural killer cell blast crisis representing an additional translocation, t(3;7)(q26;q21) in Philadelphia-positive chronic myelogenous leukemia.Henzan H et al
145517382004A novel chromosomal translocation t(3;7)(q26;q21) in myeloid leukemia resulting in overexpression of EVI1.Storlazzi CT et al

Summary

Fusion gene

MECOM/CDK6 MECOM (3q26.2) CDK6 (7q21.2) M t(3;7)(q26;q21)
Atlas Image
Partial karyotype showing an unbalanced t(3;7)(q26;q21)

Citation

Clelia Tiziana Storlazzi ; Francesco Albano

t(3;7)(q26;q21) MECOM/CDK6

Atlas Genet Cytogenet Oncol Haematol. 2005-08-01

Online version: http://atlasgeneticsoncology.org/haematological/1287/t(3;7)(q26;q21)

External Links