Test Catalog

Test Id : ML1HM

MLH1 Hypermethylation Analysis, Tumor

Useful For
Suggests clinical disorders or settings where the test may be helpful

An adjunct to MSI / Microsatellite Instability (MSI), Tumor and 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
Lists tests that are always performed, at an additional charge, with the initial tests.

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

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

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

 

See Lynch Syndrome Testing Algorithm

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test

Polymerase Chain Reaction (PCR) Analysis

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

MLH1 Hypermethylation Analys, Tumor

Aliases
Lists additional common names for a test, as an aid in searching

Hypermethylation

MLH1 Hypermethylation

Promoter Hypermethylation

MLH1HM

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

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

 

See Lynch Syndrome Testing Algorithm

Specimen Type
Describes the specimen type validated for testing

Varies

Ordering Guidance

This test is not recommended as a first-tier screening measure for hereditary nonpolyposis colon cancer (HNPCC). Refer to MSI / Microsatellite Instability (MSI), Tumor and 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's preferred screening test (BRMLH / MLH1 Hypermethylation and BRAF Mutation Analysis, Tumor) includes both MLH1 promoter hypermethylation and BRAF V600E testing.

 

Extracted DNA from tissues is not an acceptable specimen type.

Necessary Information

Pathology report must accompany specimen in order for testing to be performed.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

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.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

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 Client Test Request (T728)

-Oncology Test Request (T729)

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Hemolysis NA
Lipemia NA
Icterus NA
Other Specimens that have been decalcified (all methods); specimens that have not been formalin-fixed, paraffin-embedded; bone marrow in EDTA, extracted DNA

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

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

Useful For
Suggests clinical disorders or settings where the test may be helpful

An adjunct to MSI / Microsatellite Instability (MSI), Tumor and 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

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

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

 

See Lynch Syndrome Testing Algorithm

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Hereditary nonpolyposis colon cancer (HNPCC), also known as Lynch syndrome, is an inherited cancer syndrome caused by a germline mutation in one of several genes involved in DNA mismatch repair (MMR), including MLH1, MSH2, MSH6, and PMS2. There are several laboratory-based strategies that help establish the diagnosis of HNPCC/Lynch syndrome, including testing tumor tissue for the presence of microsatellite instability (MSI-H) and loss of protein expression for any one of the MMR proteins by immunohistochemistry (IHC). It is important to note, however, that the MSI-H tumor phenotype is not restricted to inherited cancer cases; approximately 20% of sporadic colon cancers are MSI-H. Thus, MSI-H does not distinguish between a somatic (sporadic) and a germline (inherited) mutation, nor does it identify which gene is involved. Although IHC analysis is helpful in identifying the responsible gene, it also does not distinguish between somatic and germline defects.

 

Defective MMR in sporadic colon cancer is most often due to an abnormality in MLH1, and the most common cause of gene inactivation is promoter hypermethylation (epigenetic silencing). A specific mutation in the BRAF gene (V600E) has been shown to be present in approximately 70% of tumors with hypermethylation of the MLH1 promoter. Importantly, the V600E mutation is rarely identified in cases with germline MLH1 mutations. Thus, direct assessment of MLH1 promoter methylation status and testing for the BRAF V600E mutation can be used to help distinguish between a germline mutation and epigenetic/somatic inactivation of MLH1. Tumors that have the BRAF V600E mutation and demonstrate MLH1 promoter hypermethylation are almost certainly sporadic, whereas tumors that show neither are most often caused by an inherited mutation.

 

Although testing for the BRAF V600E mutation and MLH1 promoter hypermethylation are best interpreted together, they are also available separately to accommodate various clinical situations and tumor types. These tests can provide helpful diagnostic information when evaluating an individual suspected of having HNPCC/Lynch syndrome, especially when testing is performed in conjunction with MSI / Microsatellite Instability (MSI), Tumor and Mismatch Repair (MMR) Protein Immunohistochemistry Only, Tumor studies. It should be noted that these tests are not genetic tests, but rather stratify the risk of having an inherited cancer predisposition and identify patients who might benefit from subsequent genetic testing.

 

See Lynch Syndrome Testing Algorithm

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretative report will be provided.

Interpretation
Provides information to assist in interpretation of the test results

An interpretive report will be provided. The likelihood of a germline (inherited) mutation is very low in those cases where the tumor demonstrates MLH1 promoter hypermethylation and the normal tissue is unmethylated. The likelihood of a germline mutation is high in those cases where the tumor and normal tissue lack MLH1 promoter hypermethylation. In cases where the tumor and normal tissue demonstrate MLH1 promoter hypermethylation, this result will be interpreted as equivocal and a blood sample will be requested to confirm potential germline hypermethylation.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Testing tumors other than colon or endometrial for MLH1 hypermethylation has not been fully evaluated, and these specimens are not accepted for testing.

 

Colon cancer is relatively common and it is possible for a sporadic colon cancer to occur in an HNPCC family. Therefore, evaluation of other family members should still be considered in cases with MLH1 promoter hypermethylation if there is high clinical suspicion of HNPCC.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Cunningham JM, Kim CY, Christensen ER, et al: The frequency of hereditary defective mismatch repair in a prospective series of unselected colorectal carcinomas. Am J Hum Genet 2001;69:780-790

2. Wang L, Cunningham JM, Winters JL, et al: BRAF mutations in colon cancer are not likely attributable to defective DNA mismatch repair. Cancer Res 2003;63:5209-5212

3. Domingo E, Laiho P, Ollikainen M, et al: BRAF screening as a low-cost effective strategy for simplifying HNPCC genetic testing. J Med Genet 2004;41:664-668

4. Bettstetter M, Dechant S, Ruemmele P, et al: Distinction of hereditary nonpolyposis colorectal cancer and sporadic microsatellite-unstable colorectal cancer through quantification of MLH1 methylation by real-time PCR. Clin Cancer Res 2007;13:3221-3228

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Description
Describes how the test is performed and provides a method-specific reference

A PCR-based assay is used to test tumor DNA for the presence of hypermethylation of the MLH1 promoter. This is a modification of the method described by Grady et al.(Grady WM, Rajput A, Lutterbaugh JD, Markowitz S: Detection of aberrantly methylated hMLH1 promoter DNA in the serum of patients with microsatellite unstable colon cancer. Cancer Res 2001;61:900)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Varies

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

7 to 14 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

Extracted DNA: 3 months

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

81288

 

88381

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
ML1HM MLH1 Hypermethylation Analys, Tumor 97761-1
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
53299 Result Summary 50397-9
53300 Result 82939-0
53301 Interpretation 69047-9
53302 Reason for Referral 42349-1
53303 Specimen 31208-2
53304 Source 85298-8
54447 Tissue ID 80398-1
53305 Released By 18771-6

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports