t(8;9)(p22;p24) PCM1/JAK2

2006-09-01   Andreas Reiter , Christoph Walz 

1.Medizinische Universitatsklinik, Fakultat fur Klinische Medizin Mannheim der Universitat Heidelberg, Wiesbadener Str. 7-11, 68305 Mannheim, Germany

Clinics and Pathology

Disease

The PCM1-JAK2 resulting from a t(8;9)(p22;p24) fusion gene occurs in both myeloid and lymphoid malignancies: CML-like chronic phase disease with associated eosinophilia and marrow fibrosis and possible evolvement to secondary AML and B-ALL (blast crisis), de novo B-ALL and T-ALL/T-NHL. Striking male predominance.

Phenotype stem cell origin

Atypical chronic myeloid leukemia; chronic eosinophilic leukemia; pre-B-cell acute lymphoblastic leukemia; acute myeloid leukemia M6;T-cell acute lymphoid leukemia; myelodysplastic syndrome/myeloproliferative disease, unclassifiable; secondary acute myeloid leukemia.

Epidemiology

15 published cases (plus 3 unpublished), striking male predominance, only 2 females, median age 45.5 years (range, 12-74).

Clinics

CML-like chronic phase disease with associated eosinophilia and marrow fibrosis and possible evolvement to secondary AML and B-ALL (blast crisis), de novo B-ALL and T-ALL/T-NHL. Striking male predominance, clinical course highly variable.

Treatment

Allogeneic stem cell transplantation; interferon; hydroxyurea; no specific JAK2 inhibitor currently available.

Prognosis

PCM1-JAK2 positive disease is an aggressive disease compared to patients with MPD and associated V617F JAK2 mutation. Acute leukemias (de novo and secondary) seen in approximately 50% of all cases.

Cytogenetics

Atlas Image
Figure 1. left: FISH: JAK2 breakapart probe. The der(8) is marked by the red 5JAK2 signal and the der(9) by the green 3JAK2 signal - Courtesy Marc Muller; center top: Ideogram and t(8;9)(p22;p24) QFQ-banding - Courtesy Marc Muller; center bottom: cytology - Courtesy Lucienne Michaux, Peter Meeus and Peter Vandenberghe; right: t(8;9)(p22;24) PCM1/JAK2 R-banding and FISH- Courtesy Lucienne Michaux, Peter Meeus and Peter Vandenberghe

Genes Involved and Proteins

Gene name
PCM1 (pericentriolar material 1)
Location
8p22
Dna rna description
41 exons; alternate splicing.
Protein description
PCM1 is involved in recruiting proteins necessary for centrosome replication and predicted to contain multiple coiled-coil motifs.
Gene name
JAK2 (janus kinase 2)
Location
9p24.1
Dna rna description
23 exons.
Protein description
JAK2 is a tyrosine-protein kinase with transmembrane and tyrosine kinase domains.

Result of the Chromosomal Anomaly

Description

5 PCM1 - 3 JAK2.

Transcript

PCM1-JAK2 chimeric RNA constantly present; variable positions of the breakpoints within PCM1 and JAK2; reciprocal transcript may be present.
Atlas Image
Diagrammatic representation of normal JAK2, normal PCM1 and the PCM1-JAK2 fusion protein.

Description

PCM1-JAK2 mRNA is predicted to encode a protein that retains several of the predicted coiled-coil domains from PCM1 and the entire tyrosine kinase domain of JAK2.

Oncogenesis

As has been found for other tyrosine kinase fusion proteins, e.g. BCR-ABL, it is likely that one or more of the coiled-coil motifs from PCM1 result in dimerization or oligomerization of the PCM1-JAK2 chimera, with consequent constitutive activation of the JAK2 kinase domain.

Bibliography

Pubmed IDLast YearTitleAuthors
164248652006A t(8;9) translocation with PCM1-JAK2 fusion in a patient with T-cell lymphoma.Adélaïde J et al
165649302006Myeloproliferative disorders carrying the t(8;9) (PCM1-JAK2) translocation.Bousquet M et al
160071272005JAK the trigger.Mahon FX et al
160344662005PCM1-JAK2 fusion in myeloproliferative disorders and acute erythroid leukemia with t(8;9) translocation.Murati A et al
158052632005The t(8;9)(p22;p24) is a recurrent abnormality in chronic and acute leukemia that fuses PCM1 to JAK2.Reiter A et al

Summary

Fusion gene

PCM1/JAK2 PCM1 (8p22) JAK2 (9p24.1) M t(8;9)(p22;p24)|PCM1/JAK2 PCM1 (8p22) JAK2 (9p24.1) TIC

Citation

Andreas Reiter ; Christoph Walz

t(8;9)(p22;p24) PCM1/JAK2

Atlas Genet Cytogenet Oncol Haematol. 2006-09-01

Online version: http://atlasgeneticsoncology.org/haematological/1329/t(8;9)(p22;p24)

External Links