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MOLECULAR Analysis:
Janus Kinase 2 V617F Mutation (JAK2)
Polycythemia vera (PV), essential thrombocythemia (ET), and idiopathic myelofibrosis (IMF) are clonal myeloproliferative disorders arising from hematopoietic progenitor cells. The V617F point mutation in the Janus kinase 2 (JAK2) gene has been identified in 65 – 97% of patients with PV, 23 – 57% of patients with ET, 35 – 57% of patients with IMF, and 3 – 5% of patients with myelodysplastic diseases such as atypical chronic myeloid leukemia (CML) and chronic myelomonocytic leukemia (CMML). The V617F mutation in the JAK2 gene is believed to contribute to the myeloproliferative state of these disorders.
- Confirm a diagnosis of PV, ET, and IMF
- Confirm cases of myelodysplastic disease
Direct mutation analysis: Our laboratory utilizes polymerase chain reaction (PCR) analysis followed by (1) direct sequencing of the amplicons to identify a G to T point mutation leading to a substitution of valine to phenylalanine at amino acid position 617 (V617F) and (2) restriction enzyme digestion of the amplicons and gel electrophoresis to identify the nucleotide substitution.
Lymphocyte cells do not harbor the acquired V617F mutation. False negative results may occur either in specimens containing a high percentage of non-myeloid cells or in specimens with a low percentage of granulocytes or monocytes.
Recent studies indicate an increase in sensitivity for detection of the V617F mutation in patients with polycythemia vera when results are obtained quantitatively. A quantitative assay should be considered for patients who receive a negative result with this assay particularly if MPD therapies become available.
Validation studies on a quantitative assay are currently being performed in our laboratory.
Blood: 5 cc collected in a purple top (EDTA) or yellow top (acid citrate dextrose) vacutainer tube. Do not centrifuge or freeze. Specimen may be refrigerated or stored at room temperature.
Bone marrow: 1 - 2 cc collected in a purple top (EDTA) or yellow top (acid citrate dextrose) vacutainer tube. Do not centrifuge or freeze. Specimen may be refrigerated or stored at room temperature. The specimen should reach the laboratory within 48 hours from the time of collection.
12 days
83891, 83892, 83894, 83900, 83904, 83909, 83912
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