JAK2 V617F Mutation Analysis

Background

Janus Kinase 2 (JAK2) is a cytoplasmic tryosine kinase that mediates signals from cytokine receptors. A point mutation in codon 617 (GTC<TTC), resulting in the phenylalanine for valine substitution in the regulatory domain of the JAK2 kinase, confers growth factor-independent activity. This mutation is frequently present in Myeloproliferative Disorders that are not associated with a Philadelphia chromosome. Approximately 80% of Polycythemia and 30-50% of Essential Thrombocythemia and Chronic Idiopathic Myelofibrosis patients have a heterozygous or homozygous V617F mutation in the progenitor cells that give rise to the myeloid, erythroid and megakaryocytic lineages. The JAK2 V617F mutation has also been found in smaller numbers of other Philadelphia chromosome-negative myeloproliferative disorders, including some "atypical" cases. The mutation is somatic in the majority of cases, and can be found in a subset of peripheral myeloid cells, but not in T-cells or in non-hematopoietic cells.

Clinical Utility

JAK2 V617F mutation is present in myeloproliferative neoplasms (Polycythemia vera, essential thrombocythemia and primary myelofibrosis) and some other myeloid neoplasms. The test can be done for confirmation of clinical diagnosis or presymptomatic testing.

Methodology

The JAK2 V617F c.1849G>T mutation is detected by means of an allele-specific PCR assay. This is a qualitative test and reported as positive or negative.

Specimen Requirements

  1. Peripheral Blood: 3-5 ml, collected in EDTA (purple top) tube, store at room temperature 24 hours
  2. Bone Marrow: 0.5-1 ml, collected in EDTA (purple top)tube, store at room temperature, 24 hours
  3. Unacceptable Specimens: Frozen blood or bone marrow specimens are unacceptable as are tissue samples that have undergone a freeze/thaw cycle(s).

Performed

Weekly

Turnaround time

Within 3-7 business days of receipt

CPT

81270

Shipment Must Include

Specimen
Requisition form
Patient pathology report

References

  1. Baxter, E. J., L. M. Scott, et al. (2005). Acquired mutation of the tyrosine kinase JAK2 in human myeloproliferative disorders. Lancet 365(9464): 1054-61.
  2. James, C., V. Ugo, et al. (2005). A unique clonal JAK2 mutation leading to constitutive signalling causes polycythaemia vera. Nature 434(7037): 1144-8.
  3. Jones, A. V., S. Kreil, et al. (2005). Widespread occurrence of the JAK2 V617F mutation in chronic myeloproliferative disorders. Blood. 106(6): 2162-2168.
  4. Kralovics, R., F. Passamonti, et al. (2005). A gain-of-function mutation of JAK2 in myeloproliferative disorders. N Engl J Med 352(17): 1779-90
  5. Levine, R. L., M. Loriaux, et al. (2005). The JAK2V617F activating mutation occurs in chronic myelomonocytic leukemia and acute myeloid leukemia, but not in acute lymphoblastic leukemia or chronic lymphocytic leukemia. Blood.106(10): 3377-3379
  6. Shannon, K. and R. A. Van Etten (2005). JAKing up hematopoietic proliferation. Cancer Cell 7(4): 291-3.
  7. Steensma, D. P., G. W. Dewald, et al. (2005). The JAK2 V617F activating tyrosine kinase mutation is an infrequent event in both atypical myeloproliferative disorders and myelodysplastic syndromes. Blood 106(4): 1207-9.
  8. Tefferi, A. and D. G. Gilliland (2005). JAK2 in Myeloproliferative Disorders is Not Just Another Kinase. Cell Cycle 4(8).
  9. Tefferi, A. and D. G. Gilliland (2005). The JAK2V617F tyrosine kinase mutation in myeloproliferative disorders: status report and immediate implications for disease classification and diagnosis. Mayo Clin Proc 80(7): 947-58.