CAT #: NPM1
NPM1 Mutation Detection by PCR
Description of Test:
Primers targeting exon 12 on the NPM1 gene are used to amplify the patient’s DNA. The size of the NPM1 PCR product is determined by capillary electrophoresis.
LabPMM offers the only internationally harmonized assay for NPM1 mutations.
The Nucleophosmin (NPM1) gene is one of the most commonly mutated genes in acute myeloid leukemia (AML), occurring in about 35% of AML patients at diagnosis and in approximately 60% of adult cytogenetically normal AML (CN-AML). The CN-AML group is collectively the most common AML group and assigned an intermediate prognosis. However studies have shown that the CN-AML group is not homogeneous and significant diversity has been shown to exist within this population of AML patients.
The vast majority of NPM1 mutations are insertions in exon 12 occurring near the C-terminus of the protein that result in cytoplasmic localization. Currently there are over 40 known NPM1 mutations, most of which will be detected with our assay. Clinical studies have found that NPM1 mutations are associated with increased blast counts, higher extramedullary involvement and increased platelet counts in AML. In the absence of FLT3 mutation, NPM1 mutations are associated with a good response to induction therapy and have a 60% improved 5 year survival.It has been suggested that the identification of mutations in both NPM1 and FLT3 genes allows for the stratification of the CN-AML patients into three different prognostic groups: Favorable prognosis (NPM1+ and FLT3-), intermediate prognosis (NPM1+ and FLT3+ or NPM1-and FLT3-) and poor prognosis (NPM1– and FLT3+).
It is recommended that patients who are CN-AML to be screened for NPM1 mutations in efforts to assess prognosis and aid in treatment decisions. Utilizing both NPM1 and FLT3 mutations status is the most common method in stratification of the CN-AML population.
Indications for Testing:
- At initial diagnosis of AML
- Stratifying high and low risk AML
- Recurrence of leukemia after induction therapy on patients not initially screened for NPM1 mutations.
US CPT Code:
Palmetto GBA Test Identifier:
- PBD57 – NPM1 Exon 12 Mutations
- 1-3mL of Peripheral Blood, NAHeparin, EDTA or ACD
- 0.25-1mL of bone marrow in NaHeparin, EDTA or ACD
- 250 ng of purified, high quality genomic DNA
Specimen Storage Conditions:
2-8 C for up to 7 days prior to testing
Specimen Shipping Conditions:
- Peripheral blood or bone marrow: Ambient or cool. Do not freeze.
- Isolated DNA: Ambient or frozen on dry ice.
Locations Where Test is Performed:
- San Diego, California, USA – LabPMM, LLC
- Martinsried, Germany – LabPMM GmbH
NPM1 Mutation Testing is performed pursuant to patents licensed from TrovaGene, Inc. of San Diego, CA.
- Thiede C, et al. (2006) Prevalence and prognostic impact of NPM1 mutations in 1485 adult patients with acute myeloid leukemia (AML). Blood 107:4011-4020.
- Wertheim G, et al. (2008) Nucleophosmin (NPM1) mutations in acute myeloid leukemia: an ongoing (cytoplasmic) tale of dueling mutations and duality of molecular genetic testing methodologies. J Mol Diagn 10(3):198-202.
- Falini B. et al. (2007) Translocations and mutations involving the nucleophosmin (NPM1) gene in lymphomas and leukemias. Haematologica 92(4):519-532.
- Döhner K, et al. (2005) Mutant nucleophosmin (NPM1) predicts favorable prognosis in younger adults with acute myeloid leukemia and normal cytogenetics: interaction with other gene mutations. Blood 106(12):3740-3746.
- Gale R, et al. (2008) The impact of FLT3 internal tandem duplication mutant level, number, size and interaction with NPM1 mutations in a large cohort of young adult patients with acute myeloid leukemia. Blood 111:2776-2784.