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MGMT Promoter Methylation Assay
|Utilization Guidelines||Tests with long turn-around times (ie. Molecular based tests and Microarrays) should only be requested on an inpatient if the result is going to affect the inpatient management.
If the patient will likely be discharged before the result will be available, the test should be requested after discharge. (NOTE: UCSF Medical Center is not reimbursed for inpatient testing).
An exception to the above may be appropriate if there is a possibility the patient will not survive to be discharged and the information is important for diagnosis and/or family decisions/management (ie. recurrence risk).
|Performed by||Molecular Diagnostics|
|In House Availability||Run 1x per week, DNA extraction started on Monday, day shift only|
|Method||PCR and DNA sequencing|
|Collection Instructions||Blocks selected for MGMT methylation analysis testing must contain tumor tissue.
Areas of tumor must contain at least 50% tumor cells. The lab can remove adjacent non-tumor tissue, so the entire slide does not need 50% tumor cells, just the area with tumor.
Label slides with pathology case number and block identification.
For UCSF Samples (from remote sites) Click here for sample collection instructions
For NON-UCSF Samples Click here for Requisition form & Account set-up instructions. Note we only do institutional billing.
|Sample type||Sections of Formalin-fixed, paraffin-embedded tumor tissue|
|Normal range||Normal: No methylation (less than two CpG methylation sites)|
|Synonyms||O6 methylguanine DNA methyltransferase|
|Turn around times||2-3 weeks|
|Additional information||An interpretation of this test by a laboratory physician will automatically be performed and billed for separately.
The addition of a methyl group to the O6 position of guanine is a mutagenic event that is corrected by a DNA repair protein encoded by the MGMT gene. If the MGMT repair mechanism does not occur, cells undergo apoptosis and become more susceptible to drug induced-cytotoxicity. Some glioblastoma tumors exhibit epigenetic methylation at the MGMT promoter, causing loss of MGMT gene and protein expression and culminating in the loss of DNA repair at the O6 methyl guanine.
The coupling of MGMT promoter methylation with radiotherapy and alkylating chemotherapy drugs such as carmustine or temozolomide, has been shown to increase mean patient survival. Therefore, this test is used as a prognostic indicator to treatment with alkylating agents.
This assay determines the methylation status of 6 CpG dinucleotides in a critical region of the MGMT promoter that contains Sp1 transcription factor binding sites. The result is reported as POSITIVE: METHYLATED" if two or more CpG sites are methylated in this promoter region.
This test was developed and its performance characteristics determined by the Clinical Laboratories at the Medical Center at UC San Francisco. It has not been cleared or approved by the U.S. Food and Drug Administration.
|LDT or Mod FDA?||Yes|
|Last Updated||10/24/2013 10:52:39 AM|
If you have additional questions regarding this test, please call: 415-353-1667