Specimen Collection

1. An H&E slide with the tumour region for macrodissection clearly marked by a Histopathologist. The targeted area must contain at least 30% tumour cells in a background of healthy tissue, including inflammatory cells - avoid necrotic material in the targeted area. Please include the tumour content assessed as this is an essential requirement for testing. Samples without a clearly marked target AND tumour % will not be processed.
2. A minimum of 10 unstained slides (10 micron sections) from the formalin-fixed, paraffin-embedded (FFPE) block
3. The slides and request form must contain the following matching ID?s: block number, name and NHI.
4. The test, tumour type, requesting doctor and location must be clearly stated on the referral form.
5. Slides are to be kept at room temperature at all times.

Download: - DG req form - fillable.pdf

Diagnostic Genetics Request Form

Turnaround Time: 5 days
Assay Method

The methylation status of the promoter region of the MGMT gene is determined using a methylation-specific PCR (MS-PCR). Methylation levels are assessed using the relative intensity of MS-PCR products and the following thresholds are used: unmethylated (<5%); low level methylation (5-20%); methylated (>20%). Results may be affected by factors including: intra-tumoral methylation heterogeneity, the presence of normal tissue contamination, or quality of the specimen. Therefore the clinical diagnosis or therapy should not be based solely on this assay and the results should be considered in conjunction with clinical information and additional diagnostic tests.

Diagnostic Use and Interpretation

MGMT promoter methylation testing is an essential part of molecular diagnostics for all high-grade gliomas (grade 3 and 4). MGMT is a DNA repair enzyme that reverses the DNA damage caused by alkylating agents, resulting in tumour resistance to temozolomide (TMZ) therapy. Methylation of the MGMT promoter silences MGMT, making the tumour more sensitive to treatment with alkylating agents. Patients with glioblastoma that is not MGMT promoter methylated derive less benefit from treatment with TMZ compared to those whose tumours are methylated.

References:

Cankovic et al. (2013). The role of MGMT testing in clinical practice: a report of the association for molecular pathology. The Journal of Molecular Diagnostics, 15(5), 539-555.
National Comprehensive Cancer Network. (2022). Central Nervous System Cancers (version 2.2022). Retrieved from https://www.nccn.org/professionals/physician_gls/pdf/cns.pdf

Contact Information

Diagnostic Genetics: 307 4949 (ext. 22008)

Aline Marubayashi ( alinem@adhb.govt.nz )
Chloe Pearson ( cpearson@adhb.govt.nz )

Please send all requests to the histology laboratory holding the FFPET block (for slide preparation & histopathologist assessment):
1. For FFPET samples NOT held at LabPLUS: Please send the request form and instructions to the histology laboratory holding the block.
2. For FFPET samples held at LabPLUS: Please send the request form and instructions to LabPLUS Histology Department :

Histology contacts: 307 4949 (ext. 23349)

Tania Smith ( tanias@adhb.govt.nz )
Tanya Fulton ( tanyaf@adhb.govt.nz )
Debbie O'Regan ( debbieo@adhb.govt.nz )

Specimen Transport Instructions for Referring Laboratories

When sending specimens please address the parcel to

Specimen Reception, LabPLUS

Building 31, Auckland City Hospital
Gate 4 off Grafton Rd
Grafton
Auckland
New Zealand

Last updated at 11:20:43 08/04/2024