Aiding in the distinction between a reactive cytosis and a chronic myeloproliferative disorder
Evaluating for variants in MPL in an algorithmic process
Only orderable as a reflex. For more information see MPNJM / Myeloproliferative Neoplasm, JAK2 V617F with Reflex to CALR and MPL, Bone Marrow.
Sanger Sequencing
Bone Marrow
Only orderable as a reflex. For more information see MPNJM / Myeloproliferative Neoplasm, JAK2 V617F with Reflex to CALR and MPL, Bone Marrow.
Container/Tube: Lavender top (EDTA)
Specimen Volume: 2 mL
Collection Instructions:
1. Invert several times to mix bone marrow.
2. Send specimen in original tube. Do not aliquot.
3. Label specimen as bone marrow.
0.5 mL
Gross hemolysis | Reject |
Moderately to severely clotted | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Bone Marrow | Ambient (preferred) | 7 days | |
Refrigerated | 7 days |
Aiding in the distinction between a reactive cytosis and a chronic myeloproliferative disorder
Evaluating for variants in MPL in an algorithmic process
The Janus kinase 2 gene (JAK2) codes for a tyrosine kinase (JAK2) that is associated with the cytoplasmic portion of a variety of transmembrane cytokine and growth factor receptors important for signal transduction in hematopoietic cells. Signaling via JAK2 activation causes phosphorylation of downstream signal transducers and activators of transcription (STAT) proteins (eg, STAT5) ultimately leading to cell growth and differentiation. BCR-ABL1-negative myeloproliferative neoplasms (MPN) frequently harbor an acquired single nucleotide variant in JAK2 characterized as c.G1849T; p. Val617Phe (V617F). JAK2 V617F is present in 95% to 98% of polycythemia vera and 50% to 60% of primary myelofibrosis (PMF) and essential thrombocythemia (ET) cases. It has also been described infrequently in other myeloid neoplasms, including chronic myelomonocytic leukemia and myelodysplastic syndrome. Detection of JAK2 V617F is useful to help establish the diagnosis of MPN. However, a negative JAK2 V617F result does not indicate the absence of MPN. Other important molecular markers in BCR-ABL1-negative MPN include CALR exon 9 variant (20%-30% of PMF and ET) and MPL exon 10 variant (5%-10% of PMF and 3%-5% of ET). Variants in JAK2, CALR, and MPL are essentially mutually exclusive. A CALR variant is associated with decreased risk of thrombosis in both ET and PMF and confers a favorable clinical outcome in PMF patients. A triple negative (JAK2 V617F, CALR, and MPL-negative) genotype is considered a high-risk molecular signature in PMF.
Only orderable as a reflex. For more information see MPNJM / Myeloproliferative Neoplasm, JAK2 V617F with Reflex to CALR and MPL, Bone Marrow.
An interpretive report will be provided.
An interpretation will be provided.
A positive result is not specific for a particular subtype of myeloproliferative neoplasm and clinicopathologic correlation is necessary in all cases.
A negative result does not exclude the presence of a myeloproliferative neoplasm or other neoplastic process.
Analytical sensitivity is approximately 20%, meaning there must be about 20% of the variant DNA in the specimen for reliable detection.
1. Tefferi A, Lasho TL, Finke CM, et al: CALR vs JAK2 vs MPL-mutated or triple-negative myelofibrosis: clinical, cytogenetic and molecular comparisons. Leukemia. 2014;28(7):1472-1477. doi:10.1038/leu.2014.3
2. Pikman Y, Lee BH, Mercher T, et al: MPLW515L is a novel somatic activating mutation in myelofibrosis with myeloid metaplasia. PLoS Med. 2006;3:e270. doi:10.1371/journal.pmed.0030270
3. Pardanani A, Levine R, Lasho T, et al: MPL515 mutations in myeloproliferative and other myeloid disorders: a study of 1182 patients. Blood. 2006;108:3472-3476. doi:10.1182/blood-2006-04-018879
4. Kilpivaara O, Levine RL: JAK2 and MPL mutations in myeloproliferative neoplasms: discovery and science. Leukemia. 2008;22:1813-1817. doi:10.1038/leu.2008.229
Polymerase chain reaction amplification of MPL exon 10 is performed on DNA isolated from the patient sample. The entire exon 10 sequence is obtained using Sanger sequencing with analysis on an automated genetic analyzer.(Unpublished Mayo method)
Monday through Friday
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
81339
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
MPLJM | MPL Exon 10 Mutation Detection, BM | 75033-1 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
614541 | Final Diagnosis | 22637-3 |