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FLT3 Mutation Analysis Test

Last updated Feb. 1, 2017

Approved by: Krish Tangella MD, MBA, FCAP

The FLT3 Mutation Analysis Test is a genetic test to detect abnormalities in the FLT3 gene. It is used to diagnose leukemia.

What are other Names for this Test? (Equivalent Terms)

  • Cluster of Differentiation Antigen 135 Mutation Analysis Test
  • FMS Like Tyrosine Kinase 3 Mutation Analysis Test
  • Receptor-Type Tyrosin-Protein Kinase Mutation Analysis Test

What is FLT3 Mutation Analysis Test? (Background Information)

  • FLT3 mutation refers to an alteration in the FLT3 gene. It is associated with cancer of the white blood cells (leukemia)
  • The FLT3 gene gives instructions for the FLT3 protein. The FLT3 protein plays an important role in signaling for the growth and division of white blood cells (leukocytes)
  • FLT3 belongs to a class of proteins called receptor tyrosine kinases (RTKs). As their name implies, these proteins sit outside cell membranes and serve as receptors - essentially as antennas, for compounds that stimulate cell growth and division
  • FLT3 is found on the surfaces of stem cells that are destined to become blood cells. Once FLT3 recognizes its target molecule (called FLT3L), it sets in motion powerful chemical events inside the cell with the final result of ramping up growth and division of the early blood cell
  • Normal FLT3 protein function is essential to the development of healthy blood cells, especially leukocytes. However, alterations in the FLT3 gene may result in a defective FLT3 protein that is always on (constitutively active)
  • The constitutively active FLT3 protein plays a role in turning leukocytes cancerous, by disrupting the normal signaling process responsible for balancing their growth and division
  • The FLT3 Mutation Analysis Test is a genetic test to detect abnormalities in the FLT3 gene. It is used to diagnose leukemia. It also aids in the treatment of leukemia by guiding selection of therapeutic drugs, including disqualifying certain drugs from use

The molecular testing, in general, can be performed using a variety of methods. Some of these methods include:

  • In situ hybridization technique, such as fluorescence in situ hybridization (FISH)
  • Immunohistochemistry (IHC)
  • Next-generation sequencing (NGS)
  • Polymerase chain reaction (PCR)
  • Comparative genomic hybridization (CGH)
  • Karyotyping including spectral karyotyping
  • mRNA analysis
  • Tissue microarrays (TMAs)
  • Southern blot test
  • Northern blot test
  • Western blot test
  • Eastern blot test

The methodology used for the test may vary from one laboratory to another. 

Note: Molecular testing has limitations due to the molecular method and genetic mutational abnormalities being tested. This can affect the results on a case-by-case basis. Consultation with your healthcare provider will help in determining the right test and right molecular method, based on individual circumstances.

What are the Clinical Indications for performing the FLT3 Mutation Analysis Test?

Following are the clinical indicators for performing the FLT3 Mutation Analysis Test: 

  • Fever and chills
  • Persistent fatigue, weakness
  • Frequent or severe infections
  • Losing weight without trying
  • Swollen lymph nodes, enlarged liver or spleen
  • Easy bleeding or bruising
  • Recurrent nosebleeds
  • Tiny red spots on skin (petechiae)
  • Excessive sweating, especially at night
  • Bone pain or tenderness

In general, the molecular genetic testing is undertaken in the following situations: 

  • To assist (and in some cases, confirm) the initial diagnosis
  • To distinguish other tumors/conditions that have similar histological features, when examined by a pathologist under the microscope
  • To help in determining treatment options
  • To confirm recurrence of the tumor: Tumor recurrence can either be at the original tumor site, or at a distant location (away from the initial site)

How is the Specimen Collected for the FLT3 Mutation Analysis Test?

Following is the specimen collection process for FLT3 Mutation Analysis Test:

The specimen sample requirements may vary from lab to lab. Hence, it is important to contact the testing lab for exact specimen requirements, before initiating the testing process.

  • Sample on which the test is performed may include:
    • Fresh tumor tissue during biopsy
    • Formalin-fixed paraffin-embedded solid tumor tissue (FFPE tumor tissue), often referred to as paraffin block of the tumor
    • Unstained tissue slides
  • Process of obtaining the sample: As outlined by the laboratory testing facility
  • Preparation required: As outlined by the laboratory testing facility


  • In some cases, a different source of specimen (such as peripheral blood, bone marrow biopsy specimen, or other body fluids) may be acceptable to the laboratory performing the test
  • Occasionally, additional samples may be required to either repeat the test or to perform follow-up testing
  • Depending on the location of testing, it may take up to 2 weeks’ turnaround time, to obtain the test results
  • Many hospitals preserve the paraffin blocks for at least 7 years. In general, older paraffin blocks (over 5 years) may affect the detection of specific mutations, due to degradation of the tumor specimen over time

Cost of FLT3 Mutation Analysis Test:

  • The cost of the test procedure depends on a variety of factors, such as the type of your health insurance, annual deductibles, co-pay requirements, out-of-network and in-network of your healthcare providers and healthcare facilities
  • In many cases, an estimate may be provided before the test is conducted. The final amount may depend upon the findings during the test procedure and post-operative care that is necessary (if any)

What is the Significance of the FLT3 Mutation Analysis Test Result?

  • A mutation in the FLT3 gene indicates a positive result for the FLT3 Mutation Analysis Test. This may point to a diagnosis of acute myeloid leukemia (AML)

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

  • FLT3 gene mutations are present in one-third of acute myeloid leukemia cases. The most common mutations in the FLT3 gene are internal tandem duplications (ITD) and point mutations
  • Many laboratories may not have the capability to perform this test. Only highly-specialized labs with advanced facilities and testing procedures may perform this test

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

What are some Useful Resources for Additional Information?

The following DoveMed website link is a useful resource for additional information:


Please visit our Laboratory Procedures Center for more physician-approved health information:


References and Information Sources used for the Article:

https://ghr.nlm.nih.gov/primer/testing/genetictesting (accessed on 05/10/2017)

https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5806a1.htm (accessed on 05/10/2017)

http://www.nature.com/gim/journal/v10/n5/full/gim200852a.html (accessed on 05/10/2017)

http://pediatrics.aappublications.org/content/106/6/1494 (accessed on 05/10/2017)

Mayo Clinic. (2016, January 28). Leukemia Symptoms. Retrieved from http://www.mayoclinic.org/diseases-conditions/leukemia/basics/symptoms/con-20024914

Robinson DR, Wu YM, Lin SF (November 2000). "The protein tyrosine kinase family of the human genome". Oncogene. 19 (49): 5548–57. doi:10.1038/sj.onc.1203957

Small, D. (2006). FLT3 Mutations: Biology and Treatment. Hematology, 2006(1), 178-184. doi:10.1182/asheducation-2006.1.178

Yamamoto Y, Kiyoi H, Nakano Y, Suzuki R, Kodera Y, Miyawaki S, Asou N, Kuriyama K, Yagasaki F, Shimazaki C, Akiyama H, Saito K, Nishimura M, Motoji T, Shinagawa K, Takeshita A, Saito H, Ueda R, Ohno R, Naoe T (April 2001). "Activating mutation of D835 within the activation loop of FLT3 in human hematologic malignancies". Blood. 97 (8): 2434–9. doi:10.1182/blood.V97.8.2434. PMID 11290608

Helpful Peer-Reviewed Medical Articles:

Carrano, A. V., et al. Measurement and purification of human chromosomes by flow cytometry and sorting. Proceedings of the National Academy of Sciences 76, 1382–1384 (1979)

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Pinkel, D., et al. High resolution analysis of DNA copy number variation using comparative genomic hybridization to microarrays. Nature Genetics 20, 207–211 (1998) doi:10.1038/2524

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Loke, J. C. T., Akiki, S., Borrow, J., Ewing, J., Bokhari, S. W., Chandra, D., ... & Membwange, Y. (2015). Acquired isodisomy on chromosome 13 at diagnosis results in impaired overall survival in patients with FLT3-ITD mutant acute myeloid leukaemia. Leukemia, 29(12), 2404.

Kutny, M. A., Alonzo, T. A., Gerbing, R., Wang, Y. C., Fu, C., Gamis, A. S., ... & Meshinchi, S. (2016). FLT3 Mutations in Pediatric Acute Promyelocytic Leukemia; A Report from the Children's Oncology Group AAML0631 Trial.

Burnworth, B., Bennington, R., Fritschle, W., Nguyen, P., Verkamp, S., Angela, B., ... & Zehentner, B. K. (2014). Lineage-Specific Distribution of CALR EXON 9, JAK2V617F, MPLW515L/K, NPM1 and FLT3 Mutations in Myeloid Disorders. Blood, 124(21), 5573-5573.

Galanis, A., Ma, H., Rajkhowa, T., Ramachandran, A., Small, D., Cortes, J., & Levis, M. (2014). Crenolanib is a potent inhibitor of FLT3 with activity against resistance-conferring point mutants. Blood, 123(1), 94-100.

Eckfeldt, C. E., Randall, N., Shanley, R. M., Yohe, S., Bejanyan, N., Dolan, M., ... & Weisdorf, D. J. (2016). Umbilical cord blood transplantation is a suitable option for consolidation of acute myeloid leukemia with FLT3-ITD. haematologica, 101(8), e348.

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Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Feb. 1, 2017
Last updated: Feb. 1, 2017