Sign in →

TEST ID ML1HM MLH1 Hypermethylation Analysis, Tumor

Reporting Name

MLH1 Hypermethylation Analys, Tumor

Specimen Type

Varies


Ordering Guidance


This test is not recommended as a first-tier screening measure for hereditary nonpolyposis colon cancer. For more information see TMSI / Microsatellite Instability, Tumor and IHC / Mismatch Repair (MMR) Protein Immunohistochemistry Only, Tumor.

 

Testing will only be performed on colon or endometrial tumors demonstrating loss of MLH1 protein expression by immunohistochemistry.

 

Mayo Clinic's preferred screening test includes both MLH1 promoter hypermethylation and BRAF V600E testing. Order BRMLH / MLH1 Hypermethylation and BRAF Mutation Analysis, Tumor.

 

Extracted DNA from tissues is not an acceptable specimen type.

 

If the MMR immunohistochemistry (IHC) results for MLH1 and/or PMS2 suggest possible tumor heterogeneity, are ambiguous, or unusual, the physical IHC stains will be required to optimize the area of tissue selected for testing and for interpretation of the results. If IHC stains are required and not sent with the specimen, a request will be submitted to provide the IHC stains which will result in a slight delay.



Necessary Information


Pathology report and MMR IHC results must accompany specimen in order for testing to be performed.



Specimen Required


Specimen Type: Tissue block or slide

Collection Instructions:

1. Submit formalin-fixed, paraffin-embedded tissue block (preferred) or 1 slide stained with hematoxylin and eosin and 10 unstained, nonbaked slides (5-micron thick sections) of the tumor tissue.

2. Sections should contain tumor tissue.


Specimen Minimum Volume

See Specimen Required

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Ambient (preferred)
  Frozen 
  Refrigerated 

Testing Algorithm

When this test is ordered, slide review will always be performed at an additional charge.

 

For more information see Lynch Syndrome Testing Algorithm.

Method Name

Polymerase Chain Reaction (PCR)

Reject Due To

Specimens that have been decalcified (all methods)
Specimens that have not been formalin-fixed, paraffin-embedded
Bone marrow in EDTA		 Reject

Reference Values

An interpretative report will be provided.

Day(s) Performed

Varies

Report Available

7 to 14 days

Specimen Retention Time

FFPE tissue block: Unused portions of FPPE blocks will be returned; Unused, unstained slides: 5 years; Stained slides: Indefinitely

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

81288

88381

Forms

1. Molecular Genetics: Inherited Cancer Syndromes Patient Information (T519)

2. If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Gastroenterology and Hepatology Test Request (T728)

-Oncology Test Request (T729)

Useful For

An adjunct to TMSI / Microsatellite Instability, Tumor and IHC / Mismatch Repair (MMR) Protein Immunohistochemistry Only, Tumor when colon or endometrial tumor demonstrates microsatellite instability (MSI-H) and loss of MLH1 protein expression, to help distinguish a somatic versus germline event prior to performing expensive germline testing

 

An adjunct to negative MLH1 germline testing in cases where colon or endometrial tumor demonstrates MSI-H and loss of MLH1 protein expression

Additional Tests

Test ID Reporting Name Available Separately Always Performed
SLIRV Slide Review in MG No, (Bill Only) Yes