Test Catalog

Test Id : MGMT

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MGMT Promoter Methylation, Tumor

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Overview

Test Catalog

Useful For
Suggests clinical disorders or settings where the test may be helpful

Prognostication of newly diagnosed glioblastomas

 

Identifying newly diagnosed glioblastomas that may respond to alkylating chemotherapy (ie, temozolomide)

 

Guiding therapy decision making for newly diagnosed glioblastomas in elderly patients (>60 years)

Highlights

MGMT promoter methylation status has prognostic and predictive value for glioblastoma patients

Additional Tests
Lists tests that are always performed, at an additional charge, with the initial tests.

Test Id Reporting Name Available Separately Always Performed
SLIRV Slide Review in MG No, (Bill Only) Yes

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, slide review will always be performed at an additional charge.

Method Name
A short description of the method used to perform the test

Methylation-Specific Polymerase Chain Reaction (PCR) Analysis

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

MGMT Promoter Methylation, Tumor

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, slide review will always be performed at an additional charge.

Specimen Type
Describes the specimen type validated for testing

Varies

Necessary Information

Pathology report must accompany specimen in order for testing to be performed.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Preferred:

Specimen Type: Tissue

Container/Tube: Tissue block

Collection Instructions: Submit a formalin-fixed, paraffin-embedded tissue block. At least 40% tumor is required for this assay. In general, a 6 mm x 3 mm area of tissue cut at 5-micron thickness is the minimum amount of tissue needed; this could be collected over multiple slides.

 

Acceptable:

Specimen Type: Tissue sections

Slides: 1 stained and 5 unstained

Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 5 unstained, nonbaked 5-micron thick sections of the tumor. At least 40% tumor is required for this assay. In general, a 6 mm x 3 mm area of tissue cut at 5 micron thickness is the minimum amount of tissue needed; this could be collected over multiple slides.

Forms

If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

5 unstained slides at 5-microns thickness

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Hemolysis NA
Lipemia NA
Icterus NA
Other Specimens that have been decalcified (all methods); specimens that have not been formalin-fixed, paraffin-embedded; bone marrow in EDTA

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Varies Ambient (preferred)
Frozen
Refrigerated

Useful For
Suggests clinical disorders or settings where the test may be helpful

Prognostication of newly diagnosed glioblastomas

 

Identifying newly diagnosed glioblastomas that may respond to alkylating chemotherapy (ie, temozolomide)

 

Guiding therapy decision making for newly diagnosed glioblastomas in elderly patients (>60 years)

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, slide review will always be performed at an additional charge.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Glioblastoma (WHO grade IV astrocytoma) is the most frequent malignant primary central nervous system tumor in adults. It has a very poor prognosis, with median survival of less than a year. Current standard of care consists of surgical resection followed by radiotherapy in addition to alkylating chemotherapy with temozolomide.

 

MGMT (O[6]-methylguanine-DNA methyltransferase) is a DNA repair enzyme. This enzyme rescues tumor cells from alkylating agent-induced damage, and this leads to resistance to chemotherapy with alkylating agents. Epigenetic silencing of the MGMT gene by promoter methylation results in decreased MGMT protein expression, reduced DNA repair activity, and potential increased sensitivity to therapy. MGMT promoter methylation status has been most widely evaluated by methylation-specific PCR method, which is both sensitive and specific.

 

In newly diagnosed glioblastomas, the presence of MGMT promoter methylation has been shown to be an independent favorable prognostic factor and a strong predictor of responsiveness to alkylating chemotherapy (ie, temozolomide). This is particularly relevant for elderly patients (>60 years), who usually have decreased tolerance for combined aggressive chemoradiation. For this group of patients, recent clinical trials have provided strong evidence supporting an alternative therapeutic strategy consisting of monotherapy with the alkylating agent temozolomide for patients whose tumors show MGMT promoter methylation and radiotherapy alone for patients whose tumors lack MGMT promoter methylation. Thus, in addition to the significant prognostic and predictive value, MGMT methylation status has emerged as a valuable biomarker to guide therapy decision making for newly diagnosed glioblastoma in elderly patients, preventing unnecessary treatment toxicities and costs.

 

MGMT promoter methylation has been reported to high rates in oligodendrogliomas and astrocytomas of lower grade, in which they variably correlate with 1p19q codeletion and IDH mutations. Prognostic and predictive significance of MGMT promoter methylation status in these tumors has been shown in some studies, but not in others.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Interpretation
Provides information to assist in interpretation of the test results

An interpretive report will be provided.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Not all patients whose tumors have MGMT promoter methylation will respond to alkylating chemotherapy.

 

MGMT promoter methylation status should not be used as the sole determinant of alkylating therapy eligibility.

 

Test results should be interpreted in context of clinical findings, tumor sampling, and other laboratory data. If results obtained do not match other clinical or laboratory findings, contact the laboratory for possible interpretation. Misinterpretation of results may occur if the information provided is inaccurate or incomplete.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Hegi ME, Diserens AC, Gorlia T, et al: MGMT gene silencing and benefit from temozolomide in glioblastoma. N Engl J Med 2005;352(10):997-1003

2. Weller M, Stupp R, Reifenberger G, et al: MGMT promoter methylation in malignant gliomas: ready for personalized medicine? Nat Rev Neurol 2010;6:39-51

3. Wick W, Platten M, Meisner C, et al: Temozolomide chemotherapy alone versus radiotherapy alone for malignant astrocytoma in the elderly: The NOA-08 randomised, phase 3 trial. Lancet Oncol 2012;13:707-715

4. Malmstrom A, Gronberg BH, Marosi C, et al: Temozolomide versus standard 6-week radiotherapy versus hypofractionated radiotherapy in patients older than 60 years with glioblastoma: the Nordic randomised, phase 3 trial. Lancet Oncol 2012;13:916-926

5. Wick W, Weller M, van den Bent M, et al: MGMT testing-the challenges for biomarker-based glioma treatment. Nat Rev Neurol 2014;10:372-385

Method Description
Describes how the test is performed and provides a method-specific reference

A modification of the real-time, methylation-specific PCR assay described by Kitange et al, is used to test tumor DNA for the presence of methylation of the promoter of the MGMT gene.(Kitange GJ, Carlson BL, Mladek AC, et al: Evaluation of MGMT promoter methylation status and correlation with temozolomide response in orthotopic glioblastoma xenograft model. J Neurooncol 2009 Mar;92[1]:23-31)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Varies

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

7 to 10 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

Unused portions of blocks will be returned.; Extracted (at Mayo) DNA: 3 months.; Slides are stored indefinitely.

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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 US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

81287

Slide Review

88381

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
MGMT MGMT Promoter Methylation, Tumor 60252-4
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
36734 Result Summary 50397-9
36735 Result 60252-4
36736 Interpretation 69047-9
36737 Additional Information 48767-8
36738 Specimen 31208-2
36739 Source 31208-2
36740 Tissue ID 80398-1
36741 Released by 18771-6

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports