Laboratory Test Guide

Methylguanine methyltransferase (MGMT) promoter methylation assay

General Information

Lab Name

MGMT Promoter Methylation, Somatic

Lab Code

MGMTMT

Epic Name

MGMT Promoter Methylation, Somatic

Description

The methylguanine methyltransferase (MGMT) promoter methylation assay is useful in the evaluation of malignant gliomas; methylation of the MGMT promoter occurs in approximately 40% of malignant gliomas and is a predictive biomarker for response to alkylating chemotherapy. MGMT is a DNA repair protein that reverses the desired cytotoxic effects of alkylating chemotherapeutic agents. Many clinical trials have shown that patients with a hypermethylated MGMT promoter are more likely to benefit from temozolomide (TMZ) in addition to standard surgical and radiation therapy. MGMT promoter status has recently been incorporated into adjuvant therapy guidelines provided by the US National Comprehensive Cancer Network.

Synonyms

glioblastoma, glioma, hypermethylation, methylation, methylguanine methyltransferase, MGMT, O6-methylguanine-DNA methyltransferase, promoter, temozolomide

Components

Code	Name
MGMTCH	MGMT Promoter Methylation Clinical History
MGMTRE	MGMT Promoter Methylation Result
MGMTIN	MGMT Promoter Methylation Interpretation
MGMETH	MGMT Promoter Methylation Method
MGMTDI	MGMT Promoter Methylation Director

Interpretation

Method

Tumor DNA is bisulfite converted and amplified with a PCR-based assay to assess MGMT promoter hypermethylation

Reference Range

See individual components

Guidelines

Genetics and Solid Tumor Diagnostic Testing

Ordering & Collection

Specimen Type

FFPE, Tissue

Collection

EITHER (a) slides OR (b) tissue block:

(a) Instructions for slide specimens: 1 slide at 4-micron thickness stained with hematoxylin-and-eosin AND 10 unstained, non-baked slides at 10-micron thickness (a minimum of 5 unstained slides is acceptable). Unstained slides can be on charged or uncharged slides.Note: sections should contain as much tumor as possible.

(b) Instructions for tissue block specimen: Provide complete tissue block containing tumor tissue. If there is more than one tissue block, please provide the block that has the greatest amount of tumor tissue. Tissue block will be returned at completion of testing.

Unacceptable: Decalcified sample

Handling Instructions

Attach a copy of the pathology report for the tumor sample being submitted.

Quantity

requested: Requested: Slides or tissue block as noted above.
minimum: Minimum: 5 unstained slides (10-micron thickness) with 20% tumor nuclei

Processing

Hold slides or tissue blocks at room temperature.

Outside Laboratories: Ship at room temperature.

Performance

LIS Dept Code

Genetics (GEN)

Performing Location(s)

UW-MT	Genetics Attention: Genetics Lab Clinical lab, Room NW220 University of Washington Medical Center 1959 NE Pacific Street Seattle, WA 98195 Tel: 206-598–6429 M–F (7:30 AM–4:00 PM) Fax: 206-616-4584 Lab email: cgateam@uw.edu Tel (EXOME only): 206-543-0459	Faculty Jillian Buchan, PhD, FACMG Runjun Kumar, MD, PhD Regina Kwon, MD, MPH Christina Lockwood, PhD, DABCC, DABMGG Abbye McEwen, MD, PhD Colin Pritchard, MD, PhD Vera Paulson, MD, PhD Eric Konnick, MD, MS He Fang, PhD

Frequency

Run at least once a week; Typical Turnaround: 3 weeks *Turn around times may vary based on factors such as tissue acquisition and insurance preauthorization.