MGMT (O-6-methylguanine-DNA methyltransferase) (eg, glioblastoma multiforme) promoter methylation analysis
CPT4 code
Name of the Procedure:
MGMT (O-6-methylguanine-DNA methyltransferase) Promoter Methylation Analysis
Summary
MGMT promoter methylation analysis is a laboratory test that assesses whether the MGMT gene—often implicated in brain tumors like glioblastoma multiforme—has been methylated. The test involves examining a sample of tumor DNA to determine the methylation status of the MGMT promoter region, which can influence the effectiveness of certain chemotherapy treatments.
Purpose
The analysis is primarily used to evaluate brain tumors, especially glioblastomas, and to predict the response to alkylating agent chemotherapy. When the MGMT gene promoter is methylated, the gene's expression is altered, often leading to a better response to chemotherapy.
Indications
- Diagnosed glioblastoma multiforme
- Considering treatment with alkylating chemotherapy agents like temozolomide
- Need to predict tumor response to chemotherapy for treatment planning
Preparation
- No special preparation like fasting is required.
- Tissue samples typically come from a biopsy or surgical removal of the tumor.
- Pre-procedure diagnostic imaging, such as MRI or CT scans, may be performed to locate the tumor.
Procedure Description
- Sample Collection: A tumor sample is collected during surgery or biopsy.
- DNA Extraction: DNA is extracted from the tumor tissue.
- Methylation-Specific PCR: The DNA undergoes a process called methylation-specific PCR (polymerase chain reaction) to detect the methylation status of the MGMT gene promoter.
- Analysis: The PCR results are analyzed to determine the methylation status, usually delivering results in a specialized pathology lab.
No anesthesia or sedation is involved in the laboratory analysis itself, though the initial biopsy or surgery may require such measures.
Duration
The lab analysis typically takes a few days, but the surgical procedure for obtaining the tissue sample may last several hours.
Setting
- Tissue sample collection occurs in a hospital or neurosurgical center.
- The methylation analysis is performed in a specialized pathology laboratory.
Personnel
- Neurosurgeon or radiologist for tissue collection
- Pathologists and laboratory technicians for DNA extraction and methylation analysis
Risks and Complications
- Common: Risks are mainly associated with the initial biopsy or surgical procedure, including infection, bleeding, and pain.
- Rare: Misinterpretation of results or technical errors in laboratory processing.
Benefits
- Improved Treatment Planning: Helps in tailoring chemotherapy treatment, potentially improving outcomes.
- Predictive Value: Provides valuable prognostic information that can guide treatment choices.
Recovery
- Post-Surgery/ Biopsy: Follow standard post-operative care for recovery.
- Lab Analysis: No specific post-procedure care is needed for the lab analysis.
- Follow-Up Appointments: Regular follow-ups with an oncologist to discuss the results and next treatment steps.
Alternatives
- Immunohistochemistry: Another method to assess protein expression but does not provide complete methylation status.
- Clinical Observation: Making treatment decisions based on clinical observations and imaging alone, which might not offer as precise a prediction without the genetic insights.
Patient Experience
- During Procedure: For the biopsy or surgery, patients may experience discomfort, anesthesia effects, and the typical risks associated with surgical procedures.
- After Procedure: Normal post-surgical recovery care includes pain management and infection prevention. The lab-based portion of the test is non-invasive, involving no additional patient discomfort.