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MPL Gene Mutation

ET, essential thrombocytosis, thrombocythemia, PMF, primary myelofibrosis, fibrosis, MPN, myeloproliferative neoplasm

Test Codes

EPIC: LAB6393, Beaker: GMPLG

Department

Molecular Pathology

Specimen Collection Criteria

Collect: One of the following specimens:

• Peripheral Blood: 10.0 mL whole blood in Lavender-top EDTA or Yellow-top ACD tubes. (Minimum: 5.0 mL)
• Bone Marrow Aspirate: 1.0 mL bone marrow in a Lavender-top EDTA tube. (Minimum: 0.5 mL) 

Physician Office/Draw Specimen Preparation

Do not freeze specimens. Maintain whole blood or bone marrow refrigerated (preferred) (2-8°C or 36-46°F) or at room temperature (20-26°C or 68-78.8°F) prior to transport.

Preparation for Courier Transport

Transport: 10.0 mL whole blood (Minimum: 5.0 mL) or 1.0 mL bone marrow (Minimum: 0.5 mL), at room temperature (20-26°C or 68-78.8°F) or refrigerated (preferred) (2-8°C or 36-46°F).

Rejection Criteria

• Frozen specimens.
• Centrifuged specimens.
• Mislabeled or unlabeled tubes.
• Specimens collected in heparin tubes (Green-top), clot tubes (Red-top), or SST tubes.
• Specimens not collected and processed as indicated.

Clients will be notified of any cancellations of testing. 

In-Lab Processing

Do not freeze specimens. Maintain specimen refrigerated (2-8°C or 36-46°F) prior to testing. 

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 72 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Royal Oak Molecular Pathology Laboratory

Performed

Results available within 14 days.

Reference Range

Negative for MPL mutations.

Test Methodology

Real-time polymerase chain reaction (PCR) with allelic discrimination.

Interpretation

This test detects the W515L and W515K mutations in the MPL gene. The MPL gene is a member of the hematopoietin gene superfamily and encodes the thrombopoietin receptor, facilitating global hematopoiesis and megakaryocyte growth and differentiation. The MPL mutations are gain of function mutations and induce initiating events in myeloproliferative neoplasms.

Clinical Utility

• MPL mutations have been reported in JAK 2 negative myeloproliferative neoplasms; 5-8% of patients with primary myelofibrosis and 1-3% of patients with essential thrombocythemia are positive for MPL mutations. Therefore detection of MPL mutations facilitates the diagnosis of myeloproliferative neoplasms and aids in patient monitoring, representing a useful clonal marker.
• The test is recommended in patients with BCR/ABL1 and JAK2 negative myeloproliferative neoplasms to aid in diagnosis and monitoring the malignant clone.

CPT Codes

81402

Contacts

Last Updated

11/2/2023