MLH1 Promoter Hypermethylation
Test Mnemonic
MLH1PH
CPT Codes
- 81288 - QTY (1)
Aliases
- MLH1PH
Performing Laboratory
Cleveland Clinic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| One | Paraffin block, formalin fixed | Formalin-fixed, paraffin-embedded block | N/A | Ambient | Minimum biopsy size 0.5 x 0.5 x 0.5 cm with mainly tumor tissue. Necrosis area should be less than 15%. Cut 12 charged, unbaked slides, 4um thick. Pre and post H&E slides must be examined. Tumor area will be microdissected from unstained slides. |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| One | Paraffin block, formalin fixed | Formalin-fixed, paraffin-embedded block | N/A | Ambient | Minimum biopsy size 0.5 x 0.5 x 0.5 cm with mainly tumor tissue. Necrosis area should be less than 15%. Cut 8 sections, 10 um thick and place in microcentrifuge tube. Pre and post H&E slides must be examined. |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | Ambient is the only acceptable condition |
Days Performed
2 days per week
Turnaround Time
7 days
Methodology
| Name | Description |
|---|---|
| Polymerase Chain Reaction (PCR) | |
| Pyrosequencing |
Special Info
Submit tissue specimen with anatomic pathology request form, and indicate MLH1 Promoter Hypermethylation on the form.
Clinical Info
Hypermethylation of the promoter of MLH1 in tumor tissue can inform differentiation of sporadic from hereditary tumors and guide further testing.
Clinical Limitation
MLH1 Promoter Assay detects hypermethylation in a region from -209 to -181 bases from the transcription start site of the promoter of the MLH1 gene. It does not detect methylation in other areas of the MLH1 promoter.
Clinical Reference
Methylation promoter hypermethylation present