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JAK2V617F + CALR + MPL NGS Panel

CPT

81219; 81270; 81338

Test Details

Methodology

Amplicon-based Next Generation Sequencing

Result Turnaround Time

7 days

Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Use

Molecular testing of blood or bone marrow is useful in the evaluation of suspected myeloproliferative neoplasms (MPN). Mutations in the JAK2, MPL and CALR genes are present in virtually all MPNs and their presence help distinguish benign reactive processes from clonal neoplasms. These mutations are generally considered mutually exclusive, although concurrent clones have been reported in rare patients.

The JAK2 (Janus kinase 2) gene encodes for a non-receptor protein tyrosine kinase that activates cytokine and growth factor signaling. The V617F (c.1849 G>T) mutation results in constitutive activation of JAK2 and downstream STAT5 and ERK signaling. The V617F mutation is observed in approximately 95% of polycythemia vera (PV), 60% of essential thrombocythemia (ET) and primary myelofibrosis (PMF). It is also infrequently present (3-5%) in myelodysplastic syndrome, chronic myelomonocytic leukemia and other atypical chronic myeloid disorders. JAK2 mutation allele burden correlates with clinical phenotype, with low levels of mutant allele characterized by thrombocytosis, intermediate levels with erythrocytosis and high mutant allele burden, correlating with enhanced myelopoiesis of the BM, leukocytosis, increasing spleen size and circulating CD34-positive cells.

The CALR (Calreticulin) gene encodes for a multifunctional calcium-binding protein involved in many cellular activities such as growth, proliferation, adhesion and programmed cell death. Among patients with JAK2-negative MPNs, CALR mutations are found in approximately 70% of patients with JAK2-negative essential thrombocythemia (ET) and 60-88% of patients with JAK2-negative primary myelofibrosis(PMF). Only a minority of patients (approximately 8%) with myelodysplasia have mutations in the CALR gene. CALR mutations are rarely detected in patients with de novo acute myeloid leukemia, chronic myelogenous leukemia, lymphoid leukemia or solid tumors. CALR mutations are not detected in polycythemia and generally appear to be mutually exclusive with JAK2 mutations and MPL mutations. The majority of mutational changes involve a variety of insertion or deletion mutations in exon 9 of the calreticulin gene: approximately 53% of all CALR mutations are a 52 bp deletion (type-1) while the second most prevalent mutation (approximately 32%) contains a 5 bp insertion (type-2). Other mutations (non-type 1 or type 2) are seen in a small minority of cases. CALR mutations in PMF tend to be associated with a favorable prognosis compared to JAK2V617F mutations, whereas primary myelofibrosis negative for CALR, JAK2V617F and MPL mutations (so-called triple negative) is associated with a poor prognosis and shorter survival.

The MPL (myeloproliferative leukemia virus oncogene) gene encodes the thrombopoietin receptor, which regulates hematopoiesis and megakaryopoiesis. Activating MPL mutations are associated with a subset of myeloproliferative neoplasms and acute megakaryoblastic leukemia. MPL W515 mutations are present in approximately 5-8% of patients with primary myelofibrosis (PMF) and 1-4% of patients with essential thrombocythemia (ET). The S505 mutation is detected in patients with hereditary thrombocythemia.

Limitations

This assay has a sensitivity of approximately 1% VAF for JAK2V617F mutations and 2.5% VAF for CALR and MPL mutations. Deletions in CALR up to 70 bp and insertions up to 12 bp have been detected in validation studies. 

This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.

 

References

Alghasham N, Alnouri Y, Abalkhail H, Khalil S. Detection of mutations in JAK2 exons 12-15 by Sanger sequencing. Int J Lab Hematol. 2016 Feb;38(1):34-41.26361084
Arber DA, Orazi A, Hasserjian R, et al. The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia. Blood. 2016 May 19;127(20):2391-2405.27069254
Ma W, Kantarjian H, Zhang X, et al. Mutation profile of JAK2 transcripts in patients with chronic myeloproliferative neoplasias. J Mol Diagn. 2009 Jan;11(1):49-53.19074595
NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) Myeloproliferative Neoplasms Version 3.2022 - August 11, 2022.
Swerdlow SH, editor. WHO classification of Tumours of Haematopoietic and Lymphoid Tissues. 4th edn. Lyon, France: International Agency for Research on Cancer; 2017.
Tefferi A. Primary myelofibrosis: 2021 update on diagnosis, risk-stratification and management. Am J Hematol. 2021 Jan;96(1):145-162.33197049
Vainchenker W, Kralovics R. Genetic basis and molecular pathophysiology of classical myeloproliferative neoplasms. Blood. 2017 Feb 9;129(6):667-679.28028029

Specimen Requirements

Specimen

Whole blood or bone marrow

Volume

3 to 5 mL whole blood or 1 to 2 mL bone marrow

Minimum Volume

3 mL whole blood or 1 mL bone marrow

Container

Lavender-top (EDTA) tube, green-top (sodium heparin) tube, yellow-top (ACD) tube, tan-top (K2-EDTA) tube or pink-top (K2-EDTA) tube

Collection Instructions

Submit at room temperature. Specimens should arrive in the laboratory within 48 hours of collection. Indicate date and time of collection on test request form.

Storage Instructions

Ship at room temperature. If specimen is to be stored prior to shipment, store at 2°C to 8°C.

Causes for Rejection

Specimen does not meet all of the criteria for sample type, container, minimum volume, collection and storage; frozen whole blood or marrow; leaking tube; clotted blood or marrow; grossly hemolyzed or otherwise visibly degraded; contamination by another specimen; specimen containing foreign material

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
489615 NGS JAK2 V617F/CALR/MPL 489532 Specimen Type 66746-9
489615 NGS JAK2 V617F/CALR/MPL 489616 JAK2 V617F Result 43399-5
489615 NGS JAK2 V617F/CALR/MPL 489617 JAK2 V617F % % 53761-3
489615 NGS JAK2 V617F/CALR/MPL 489618 CALR Result 77174-1
489615 NGS JAK2 V617F/CALR/MPL 489619 CALR % % N/A
489615 NGS JAK2 V617F/CALR/MPL 489620 CALR Nucleotide 48004-6
489615 NGS JAK2 V617F/CALR/MPL 489621 CALR Amino Acid 48005-3
489615 NGS JAK2 V617F/CALR/MPL 489622 MPL Result 75033-1
489615 NGS JAK2 V617F/CALR/MPL 489623 MPL % % N/A
489615 NGS JAK2 V617F/CALR/MPL 489624 MPL Nucleotide 48004-6
489615 NGS JAK2 V617F/CALR/MPL 489625 MPL Amino Acid 48005-3
489615 NGS JAK2 V617F/CALR/MPL 489626 JAK2 V617F/CALR/MPL Background 62364-5
489615 NGS JAK2 V617F/CALR/MPL 489627 Method 49549-9
489615 NGS JAK2 V617F/CALR/MPL 489628 References 75608-0
489615 NGS JAK2 V617F/CALR/MPL 489629 Director Review 72486-4
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489532
Result Code NameSpecimen Type
UofM
Result LOINC66746-9
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489616
Result Code NameJAK2 V617F Result
UofM
Result LOINC43399-5
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489617
Result Code NameJAK2 V617F %
UofM%
Result LOINC53761-3
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489618
Result Code NameCALR Result
UofM
Result LOINC77174-1
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489619
Result Code NameCALR %
UofM%
Result LOINCN/A
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489620
Result Code NameCALR Nucleotide
UofM
Result LOINC48004-6
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489621
Result Code NameCALR Amino Acid
UofM
Result LOINC48005-3
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489622
Result Code NameMPL Result
UofM
Result LOINC75033-1
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489623
Result Code NameMPL %
UofM%
Result LOINCN/A
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489624
Result Code NameMPL Nucleotide
UofM
Result LOINC48004-6
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489625
Result Code NameMPL Amino Acid
UofM
Result LOINC48005-3
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489626
Result Code NameJAK2 V617F/CALR/MPL Background
UofM
Result LOINC62364-5
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489627
Result Code NameMethod
UofM
Result LOINC49549-9
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489628
Result Code NameReferences
UofM
Result LOINC75608-0
Order Code489615
Order Code NameNGS JAK2 V617F/CALR/MPL
Order Loinc
Result Code489629
Result Code NameDirector Review
UofM
Result LOINC72486-4