CAT #: NPM1
NPM1 Mutation Assay
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.1 The vast majority of NPM1 mutations are insertions in exon 12 occurring near the C-terminus of the protein that result in cytoplasmic localization.2 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.3 Furthermore, in the absence of a FLT3 ITD mutation (or FLT3 ITD with a low ratio), NPM1 mutations are associated with a favorable prognosis.4 It has been suggested that the identification of mutations in both NPM1 and FLT3 genes allows for the stratification of the AML patients into three different prognostic groups:
- Favorable prognosis: NPM1 mutation without FLT3 ITD or with FLT3 ITDlow
- Intermediate prognosis: NPM1 mutation and FLT3 ITDhigh; NPM1– without FLT3 ITD or with FLT3 ITDlow (without adverse-risk genetic lesions)
- Poor prognosis: NPM1 wild-type and FLT3 ITDhigh
It is recommended that AML patients be screened for NPM1 mutations as an effort to assess prognosis and aid in treatment decisions. Results from NPM1 and FLT3 mutational screening should be available within 48 to 72 hours (at least in patients eligible for intensive chemotherapy). Utilizing both NPM1 and FLT3 (mutant:wild-type ratio) mutation status is the most common molecular method for stratification of the AML population.
Indications for Testing:
- Patients diagnosed with AML
- Stratify high and low risk AML
- Recurrence of leukemia after induction treatment in patients not initially screened for NPM1 mutations
US CPT Code:
Palmetto GBA Test Identifier:
- PBD57 – NPM1 Exon 12 Mutations
- Service Description:
NPM1 mutation testing is performed pursuant to patents licensed from TrovaGene, Inc. of San Diego, CA.
1. Thiede, C et al. (2006) Blood. 107:4011-4020.
2. Falini, B et al. (2007) Haematologica. 92(4):519-532.
3. Döhner, K et al. (2005) Blood. 106(12):3740-3746.
4. Döhner, H et al. (2017) Blood. 129:424-447.