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Test Code KITE KIT Mutation Exons 8-11 and 17, Hematologic Neoplasms, Sequencing

Useful For

The prognostic assessment of acute myeloid leukemias with core binding factor translocations (inv16 or t[16;16] CBFB-MYH11 or t[8;21] RUNX1-RUNX1T1) and to help establish the diagnosis in some cases of mastocytosis

Method Name

Mutation Detection in DNA Using Sanger Sequencing

Reporting Name

KIT Mutation, Hematologic Neoplasm

Specimen Type

Varies


Advisory Information


This test is intended for detection of KIT mutations in "core-binding factor" (CBF) acute myeloid leukemias (AML).   For systemic mastocytosis, see KITB / KIT Asp816Val Mutation Analysis, Blood; KITBM / KIT Asp816Val Mutation Analysis, Qualitative PCR, Bone Marrow; or KITAS / KIT Asp816Val Mutation Analysis, Qualitative PCR).

Shipping Instructions


Specimen must arrive within 7 days (168 hours) of collection.



Necessary Information


The following information is required:

1. Pertinent clinical history

2. Clinical or morphologic suspicion

3. Date and time of collection

4. Specimen source



Specimen Required


Submit only 1 of the following specimens:

 

Specimen Type: Blood

Container/Tube: EDTA (lavender top) or ACD (yellow top)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

3. Label specimen as blood.

Specimen Stability: Ambient (preferred)/Refrigerate

 

Specimen Type: Bone marrow

Container/Tube: EDTA (lavender top) or ACD (yellow top)

Specimen Volume: 2 mL

Collection Instructions:

1. Invert several times to mix bone marrow.

2. Send specimen in original tube.

3. Label specimen as bone marrow.

Specimen Stability: Ambient (preferred)/Refrigerate

 

Specimen Type: Extracted DNA from blood or bone marrow

Container/Tube: 1.5- to 2-mL tube

Specimen Volume: Entire specimen

Collection Instructions: Label specimen as extracted DNA from blood or bone marrow with an indication of volume and concentration of the DNA.

Specimen Stability: Frozen (preferred)/Refrigerate/Ambient

 

Specimen Type: Paraffin-embedded tissue

Container/Tube: Paraffin block

Specimen Volume: Entire block

Specimen Stability: Ambient (preferred)/Refrigerate

 

Specimen Type: Paraffin-embedded bone marrow aspirate clot

Container/Tube: Paraffin block

Specimen Volume: Entire block

Specimen Stability: Ambient (preferred)/Refrigerate

 

Specimen Type: Unstained Slides

Container/Tube: Unstained tissue slides

Specimen Volume: 10 slides

Specimen Stability: Ambient (preferred)/Refrigerate


Specimen Minimum Volume

Blood, Bone Marrow: 1 mL; Extracted DNA: 20 mcL

Specimen Stability Information

Specimen Type Temperature Time
Varies Varies 7 days

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

NA

Icterus

NA

Other

Bone marrow biopsies, slides, paraffin shavings, frozen tissues, or moderately to severely clotted

Clinical Information

Acquired mutations in the KIT gene are identified in a subset of acute myeloid leukemias (AML) characterized by inv16 or t(16;16) CBFB-MYH11 or t(8;21) RUNX1-RUNX1T1 genetic abnormalities (approximately 10%-20% of cases) and in this setting, the additional presence of KIT gene mutation has been described as an adverse prognostic factor in some studies. KIT mutations in AML tend to involve exons 8 through 11 and 17, although the p.Asp816Val (D816V) variant that is highly prevalent in systemic mastocytosis is less common in AML. Mastocytosis is a hematologic disorder characterized by abnormal mast cell expansion in the bone marrow and extramedullary organ sites (eg, skin, gastrointestinal tract). Disease can be localized to skin (ie, cutaneous mastocytosis) or present systemically, with variable features of disease aggressiveness and symptomatology. Mutations in the KIT gene are identified in a large majority of patients with both cutaneous mastocytosis (CM) and systemic mastocytosis (SM). The D816V abnormality is identified in most patients with SM and this finding represents an important minor diagnostic criterion in the 2008 WHO classification. The D816V is less commonly seen in CM, although single nucleotide variants are present in other KIT exons. Rare cases of familial mastocytosis are also described with KIT mutations involving exons 8 and 9. Although KIT gene mutation represents an important diagnostic marker for SM, the number of bone marrow mast cells is often limited in aspirate samples. Therefore, if SM is clinically and pathologically suspected, KIT testing should first proceed with a sensitive and specific screen for the D816V (KITB / KIT Asp816Val Mutation Analysis, Blood; KITBM / KIT Asp816Val Mutation Analysis, Qualitative PCR, Bone Marrow; or KITAS / KIT Asp816Val Mutation Analysis, Qualitative PCR) prior to consideration of KIT gene sequencing, based on the greatly enhanced sensitivity of the PCR test for this particular variant. In AML, KIT sequencing is preferred, given the wider spectrum of mutations in other KIT exons.

Reference Values

An interpretive report will be provided

Interpretation

Mutations detected or not detected. An interpretive report will be issued.

Clinical Reference

1. Orfao A, Garcia-Montero AC, Sanchez L, et al: Recent advances in the understanding of mastocytosis: the role of KIT mutations. Br J Haematol 2007;138:12-30

2. Arock M, Sotlar K, Broesby-Olsen S, et al: KIT mutation analysis in mast cell neoplasms: recommendations of the European Competence Network on Mastocytosis. Leukemia 2015;6:1223-1232

3. Paschka P, Du J, Schlenk RF, et al: Secondary genetic lesions in acute myeloid leukemia with inv(16) or t(16;16): a study of the German-Austrian AML Study Group (AMLSG). Blood 2013;121:170-177

4. Pardanani A: Systemic mastocytosis in adults: 2012 Update on diagnosis, risk stratification, and management. Am J Hematol 2012;87:402-411

5. Paschka P, Marcucci G, Rupprt AS, et al: Adverse prognostic significance of KIT mutations in adult acute myeloid leukemia with inv(16) and t(8;21): a Cancer and Leukemia Group B Study. J Clin Oncol 2006;24:3905-3911

Day(s) and Time(s) Performed

Monday through Friday

Analytic Time

5 days

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81272 – KIT (v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog) (eg, gastrointestinal stromal tumor [GIST], acute myeloid leukemia, melanoma), gene analysis, targeted sequence analysis (eg, exons 8, 11, 13, 17, 18)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
KITE KIT Mutation, Hematologic Neoplasm In Process

 

Result ID Test Result Name Result LOINC Value
39426 KIT Sequencing Result In Process
MP027 Specimen Type 31208-2
37921 Final Diagnosis In Process

Forms

1. Hematopathology Patient Information (T676) in Special Instructions

2. If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request Form (T726) with the specimen (www.mayomedicallaboratories.com/media/customer-service/forms/hematopathology-request-form.pdf).