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MGMT (O6-Methylguanine-DNA Methyltransferase) Gene Methylation Assay

CPT

81287; 88381

Synonyms
  • O6-Methylguanine-DNA Methyltransferase (MGMT)

Test Details

Methodology

Quantitative methylation-specific polymerase chain reaction (PCR)

Result Turnaround Time

7 - 10 days

Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Related Documents

For more information, please view the literature below.

MGMT Gene Methylation Assay: A Biomarker for Therapy Consideration in Glioblastoma

Use

MGMT (O6-methylguanine-DNA methyltransferase) is a DNA repair enzyme that is involved in the repair of damage caused by a variety DNA cross-linking compounds, including alkylating agents. Increased methylation of the MGMT gene promoter region causes diminished or silenced expression of the gene, making cells more sensitive to DNA damage. The relationship has been shown for glioblastomas and alkylating agents such as temozolomide (Temodar®).

Special Instructions

Please provide a copy of the pathology report. Sample submission without a copy of the pathology report may delay testing. Please direct any questions regarding this test to customer service at 800-345-4363.

Limitations

Preparation of DNA from tissue samples is dependent upon the quality of the provided specimen. Inadequate DNA extraction may occur in a significant number of paraffin-embedded samples.

References

Brandes AA, Franceschi E, Tosoni A, et al. MGMT promoter methylation status can predict the incidence and outcome of pseudoprogression after concomitant radiochemotherapy in newly diagnosed glioblastoma patients. J Clin Oncol. 2008 May 1; 26(13):2192-2197.18445844
Hau P, Stupp R, Hegi ME. MGMT methylation status: The advent of stratified therapy in glioblastoma? Dis Markers. 2007; 23(1-2):97-104.17325429
Hegi ME, Diserens AC, Gorlia T, et al. MGMT gene silencing and benefit from temozolomide in glioblastoma. N Engl J Med. 2005 Mar 10; 352(10):997-1003.15758010
Vlassenbroeck I, Califice S, Diserens AC, et al. Validation of real-time methylation-specific PCR to determine O6-methylguanine-DNA methyltransferase gene promoter methylation in glioma. J Mol Diagn. 2008 Jul; 10(4):332-337.18556773

Custom Additional Information

Approximately 40% to 50% of glioblastoma multiforme (GBM) tumors exhibit MGMT gene methylation. Retrospective studies have shown that detection of MGMT promoter methylation in tumor samples is associated with an increased likelihood of a favorable response to temozolomide.

Specimen Requirements

Specimen

Glioblastoma specimens in formalin-fixed, paraffin-embedded (FFPE) tissue blocks or slides

Volume

FFPE tissue block or eight unstained slides at 5 μM and one matching H&E slide or nine precut unstained slides from a paraffin block in 5-μM sections

Minimum Volume

50mm2 total tumor area is required for testing. Two unstained slides at 5 μM and one matching H&E slide or three unstained slides at 5 μM.

Collection Instructions

FFPE tissue block or eight unstained slides at 5 μM and one matching H&E slide or nine precut unstained slides from a paraffin block in 5-μM sections

Storage Instructions

Maintain blocks/slides at room temperature.

Causes for Rejection

Tissue is not primary brain tumor; tumor block containing insufficient tumor tissue; tumor fixed in a heavy metal fixative; broken or stained slides; decalcified specimens

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
489280 MGMT Methylation Assay 60252-4 489281 Result: 60252-4
489280 MGMT Methylation Assay 60252-4 489268 Methylation Score: 64083-9
489280 MGMT Methylation Assay 60252-4 489283 Block Number: N/A
489280 MGMT Methylation Assay 60252-4 489284 Background: 77202-0
489280 MGMT Methylation Assay 60252-4 489299 Methodology: 49549-9
489280 MGMT Methylation Assay 60252-4 489286 References: N/A
489280 MGMT Methylation Assay 60252-4 489282 Director Review: 72486-4
489280 MGMT Methylation Assay 60252-4 480903 Microdissection Performed 8100-0
Order Code489280
Order Code NameMGMT Methylation Assay
Order Loinc60252-4
Result Code489281
Result Code NameResult:
UofM
Result LOINC60252-4
Order Code489280
Order Code NameMGMT Methylation Assay
Order Loinc60252-4
Result Code489268
Result Code NameMethylation Score:
UofM
Result LOINC64083-9
Order Code489280
Order Code NameMGMT Methylation Assay
Order Loinc60252-4
Result Code489283
Result Code NameBlock Number:
UofM
Result LOINCN/A
Order Code489280
Order Code NameMGMT Methylation Assay
Order Loinc60252-4
Result Code489284
Result Code NameBackground:
UofM
Result LOINC77202-0
Order Code489280
Order Code NameMGMT Methylation Assay
Order Loinc60252-4
Result Code489299
Result Code NameMethodology:
UofM
Result LOINC49549-9
Order Code489280
Order Code NameMGMT Methylation Assay
Order Loinc60252-4
Result Code489286
Result Code NameReferences:
UofM
Result LOINCN/A
Order Code489280
Order Code NameMGMT Methylation Assay
Order Loinc60252-4
Result Code489282
Result Code NameDirector Review:
UofM
Result LOINC72486-4
Order Code489280
Order Code NameMGMT Methylation Assay
Order Loinc60252-4
Result Code480903
Result Code NameMicrodissection Performed
UofM
Result LOINC8100-0