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TET2 Mutation Analysis Test

Last updated May 31, 2017

The TET2 Mutation Analysis Test detects abnormalities in the TET2 gene. It helps diagnose blood cell cancers, such as cancer of the white blood cells (leukemia), and other conditions.


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

  • MGC125715 Mutation Analysis Test
  • Probable Methylcytosine Dioxygenase TET2 Mutation Analysis Test
  • Tet Oncogene Family Member 2 Mutation Analysis Test

What is TET2 Mutation Analysis Test? (Background Information)

  • TET2 mutation refers to an alteration in the TET2 gene. It is associated with abnormal blood cell growth and development
  • The TET2 gene gives instructions for the TET2 protein (or tet methylcytosine dioxygenase 2 protein). The exact function of the TET2 protein is unknown
  • However, based on the function of similar proteins, it is estimated that the TET2 protein helps prevent early blood cells from turning cancerous. It is believed to be a tumor suppressor
  • TET2 purportedly suppresses tumors by controlling the process of converting genetic material to proteins. It helps restrain growth and development of early blood cells
  • Changes to the TET2 gene may result in a TET2 protein that is defective. The defective TET2 protein is unable to act as a tumor suppressor, and the individual may develop bone cell disorders and cancers
  • The TET2 Mutation Analysis Test detects abnormalities in the TET2 gene. It helps diagnose blood cell cancers, such as cancer of the white blood cells (leukemia), and other conditions.

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

  • In situ hybridization techniques, 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 TET2 Mutation Analysis Test?

Following are the clinical indications for performing the TET2 Mutation Analysis Test: 

  • Fever or 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 in the 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
  • If there is a family history of the medical disorder/condition
  • To distinguish other conditions that have similar features (signs and symptoms)
  • 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 TET2 Mutation Analysis Test?

Following is the specimen collection process for TET2 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:
    • Peripheral blood in individuals showing signs and symptoms suspected of TTT
    • In case of expectant mothers, prenatal testing through amniotic fluid and chorionic villi sampling
    • Fresh tumor tissue during biopsy: In some cases, the testing can be performed on tumor tissue also
    • 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

Note:

  • 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 TET2 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 TET2 Mutation Analysis Test Result?

The presence of a mutation in the TET2 gene indicates a positive result for the TET2 Mutation Analysis Blood Test. This may point to a diagnosis of any of the following:

  • Leukemia
  • Essential thrombocythemia
  • Polycythemia vera
  • Primary myelofibrosis
  • Myelodysplastic syndrome

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:

  • The TET2 gene resides on a position of the chromosome called 4q24 i.e., the long (q) arm of chromosome 4 in location 24
  • 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, 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?

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

http://www.dovemed.com/common-procedures/procedures-laboratory/

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)

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

TET2 gene - Genetics Home Reference. (n.d.). Retrieved from https://ghr.nlm.nih.gov/gene/TET2#location

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)

Drets, M. E., & Shaw, M. W. Specific banding patterns of human chromosomes. Proceedings of the National Academy of Sciences 68, 2073–2077 (1971)

Druker, B. J. Perspectives on the development of a molecularly targeted agent. Cancer Cell 1, 31–36 (2002)

Parra, I., & Windle, B. High resolution visual mapping of stretched DNA by fluorescent hybridization. Nature Genetics 5, 17–21 (1993) doi:10.1038/ng0993-17

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

Speicher, M. R., et al. Karyotyping human chromosomes by combinatorial multi-fluor FISH. Nature Genetics 12, 368–375 (1996) doi:10.1038/ng0496-368

Figueroa, M. E., Abdel-Wahab, O., Lu, C., Ward, P. S., Patel, J., Shih, A., ... & Tallman, M. S. (2010). Leukemic IDH1 and IDH2 mutations result in a hypermethylation phenotype, disrupt TET2 function, and impair hematopoietic differentiation. Cancer cell, 18(6), 553-567.

Busque, L., Patel, J. P., Figueroa, M. E., Vasanthakumar, A., Provost, S., Hamilou, Z., ... & Hassimi, M. (2012). Recurrent somatic TET2 mutations in normal elderly individuals with clonal hematopoiesis. Nature genetics, 44(11), 1179-1181.

Chou, W. C., Chou, S. C., Liu, C. Y., Chen, C. Y., Hou, H. A., Kuo, Y. Y., ... & Tsay, W. (2011). TET2 mutation is an unfavorable prognostic factor in acute myeloid leukemia patients with intermediate-risk cytogenetics. Blood, 118(14), 3803-3810.

Itzykson, R., Kosmider, O., Cluzeau, T., Mansat-De Mas, V., Dreyfus, F., Beyne-Rauzy, O., ... & Preudhomme, C. (2011). Impact of TET2 mutations on response rate to azacitidine in myelodysplastic syndromes and low blast count acute myeloid leukemias. Leukemia, 25(7), 1147-1152.

Metzeler, K. H., Maharry, K., Radmacher, M. D., Mrózek, K., Margeson, D., Becker, H., ... & Wu, Y. Z. (2011). TET2 mutations improve the new European LeukemiaNet risk classification of acute myeloid leukemia: a Cancer and Leukemia Group B study. Journal of clinical oncology, 29(10), 1373-1381.

Kohlmann, A., Klein, H. U., Weissmann, S., Bresolin, S., Chaplin, T., Cuppens, H., ... & Hebestreit, K. (2011). The Interlaboratory RObustness of Next-generation sequencing (IRON) study: a deep sequencing investigation of TET2, CBL and KRAS mutations by an international consortium involving 10 laboratories. Leukemia, 25(12), 1840-1848.

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: May 31, 2017
Last updated: May 31, 2017