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Inv(16), CBFB-MYH Mutation Analysis Test

Last updated July 26, 2019

Approved by: Maulik P. Purohit MD MPH

The Inv(16), CBFB-MYH Mutation Analysis Test is a genetic test that detects the inv(16), CBFB-MYH mutation. It is used to diagnose AML subtype M4Eo.


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

  • Inv(16)(p13q22) Mutation Analysis Test

What is Inv(16), CBFB-MYH Mutation Analysis Test? (Background Information)

  • Inv(16), CBFB-MYH mutation refers to the fusion of the CBFB and MYH11 genes, which is associated with cancer of the white blood cells (leukemia). It is specifically associated with acute myeloid leukemia (AML) type M4Eo
  • The CBFB gene is required for the proper development of early blood cells into white blood cells (leukocytes). However, the fusion protein that results from the inv(16), CBFB-MYH mutation is unable to perform its function
  • It is unclear exactly how this fusion turns normal leukocytes into cancerous ones. However, some of the effects of the fusion mutations on developing white blood cells include slowed maturation and inability to self-destruct following exposure to harmful mutation-causing chemicals
  • The Inv(16), CBFB-MYH Mutation Analysis Test is a genetic test that detects the inv(16), CBFB-MYH mutation. It is used to diagnose AML subtype M4Eo. It also aids in the treatment of AML 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 Inv(16), CBFB-MYH Mutation Analysis Test?

Following are the clinical indications for performing the Inv(16), CBFB-MYH Mutation Analysis Test include:

  • Fever
  • Bone pain
  • Lethargy and fatigue
  • Shortness of breath
  • Pale skin
  • Frequent infections
  • Easy bruising
  • Unusual bleeding, such as frequent nosebleeds and bleeding from the gums

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 Inv(16), CBFB-MYH Mutation Analysis Test?

Following is the specimen collection process for Inv(16), CBFB-MYH 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

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 Inv(16), CBFB-MYH 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 Inv(16), CBFB-MYH Mutation Analysis Test Result?

  • The presence of the inv(16), CBFB-MYH mutation indicates a positive result for the Inv(16), CBFB-MYH Mutation Analysis Test. This may point to a diagnosis of acute myeloid leukemia (AML) subtype M4Eo

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:

  • Inv(16)(p13q22) is shorthand for “inversion (inv) mutation at the long (q) arm of chromosome 13 in position 22”
  • 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.

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

http://www.dovemed.com/diseases-conditions/leukemia-and-lymphoma/

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:


Helpful Peer-Reviewed Medical Articles:


Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: May 29, 2017
Last updated: July 26, 2019