An adjunct to MSI / Microsatellite Instability (MSI), Tumor and IHC / Mismatch Repair (MMR) Protein Immunohistochemistry Only, Tumor testing, when colon 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 tumor from the same patient demonstrates MSI-H and loss of MLH1 protein expression
If this test is ordered in conjunction with the MLH1 immunostain (IHC / Mismatch Repair [MMR] Protein Immunohistochemistry Only, Tumor) and MSI (MSI / Microsatellite Instability [MSI], Tumor), this test will only be performed when clinically indicated.
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
PBMLH | MLH1 Hypermethylation/BRAF Mutation | No | Yes |
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
BMLHH | MLH1 Hypermethylation Analysis | Yes, (order ML1HM) | No |
BBRAF | BRAF Analysis | Yes, (order BRAFD) | No |
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
SLIRV | Slide Review in MG | No, (Bill Only) | Yes |
When this test is ordered, BRAF analysis and MLH1 hypermethylation analysis will always be performed. The exception would be if the tissue origin is an endometrial tumor; in those cases, only the MLH1 hypermethylation analysis component will be performed.
When this test is ordered, slide review will always be performed at an additional charge.
Methylation-Specific Polymerase Chain Reaction (PCR) and Digital Droplet Polymerase Chain Reaction (ddPCR)
BRAF Mutation
BRAF V600E
Hypermethylation
MLH1 Hypermethylation
Promoter Hypermethylation
MLBRF
Lynch syndrome
When this test is ordered, BRAF analysis and MLH1 hypermethylation analysis will always be performed. The exception would be if the tissue origin is an endometrial tumor; in those cases, only the MLH1 hypermethylation analysis component will be performed.
When this test is ordered, slide review will always be performed at an additional charge.
Varies
This test is not recommended as a first-tier screening for Lynch syndrome. Order TMSI / Microsatellite Instability, Tumor and IHC / Mismatch Repair (MMR) Protein Immunohistochemistry Only.
This test will only be performed on colon tumors demonstrating loss of MLH1 protein expression.
Pathology report must accompany specimen in order for testing to be performed.
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 both tumor and normal tissue.
1. Molecular Genetics: Inherited Cancer Syndromes Patient Information (T519)
2. If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.
Specimens that have been decalcified (all methods) Specimens that have not been formalin-fixed, paraffin-embedded Extracted DNA | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Ambient (preferred) | ||
Frozen | |||
Refrigerated |
An adjunct to MSI / Microsatellite Instability (MSI), Tumor and IHC / Mismatch Repair (MMR) Protein Immunohistochemistry Only, Tumor testing, when colon 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 tumor from the same patient demonstrates MSI-H and loss of MLH1 protein expression
If this test is ordered in conjunction with the MLH1 immunostain (IHC / Mismatch Repair [MMR] Protein Immunohistochemistry Only, Tumor) and MSI (MSI / Microsatellite Instability [MSI], Tumor), this test will only be performed when clinically indicated.
When this test is ordered, BRAF analysis and MLH1 hypermethylation analysis will always be performed. The exception would be if the tissue origin is an endometrial tumor; in those cases, only the MLH1 hypermethylation analysis component will be performed.
When this test is ordered, slide review will always be performed at an additional charge.
Lynch syndrome is an inherited cancer syndrome caused by a germline pathogenic variant 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 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) etiology, 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 alteration 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 alteration is rarely identified in cases with germline MLH1 pathogenic variants. Thus, direct assessment of MLH1 promoter methylation status and testing for the BRAF V600E alteration can be used to help distinguish between germline etiologyand epigenetic/somatic inactivation of MLH1. Tumors that have the BRAF V600E alteration and demonstrate MLH1 promoter hypermethylation are almost certainly sporadic, whereas tumors that show neither are most often caused by an inherited (germline) pathogenic variant.
Although testing for the BRAF V600E alteration 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 Lynch syndrome, especially when testing is performed in conjunction with MSI / Microsatellite Instability (MSI), Tumor and IHC / Mismatch Repair (MMR) Protein Immunohistochemistry Only, Tumor. 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
An interpretive report will be provided.
An interpretive report will be provided.
Testing tumors other than colon (in the evaluation of Lynch syndrome) for BRAF and MLH1 hypermethylation has not been fully evaluated; therefore, other specimens are not accepted.
Colon cancer is relatively common, and it is possible for a sporadic colon cancer to occur in a Lynch syndrome family. Therefore, evaluation of other family members should still be considered in cases with MLH1 promoter hypermethylation and absence of the BRAF V600E alteration if there is high clinical suspicion of Lynch syndrome.
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
5. Gupta S, Provenzale D, Llor X, et al: NCCN Guidelines Insights: Genetic/familial high-risk assessment: colorectal, version 2.2019. J Natl Compr Canc Netw. 2019;17(9):1032-1041
A methylation-specific polymerase chain reaction (PCR)-based assay is used to test tumor DNA for the presence of hypermethylation of the MLH1 promoter, based on 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), and digital droplet PCR (ddPCR) is used to test for the presence of the V600E alteration within the BRAF gene.(Unpublished Mayo method)
Varies
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
Slide Review
88381-Microdissection, manual
81210-BRAF (v-raf murine sarcoma viral oncogene homolog B1) (eg, colon cancer), gene analysis, V600E variant, if appropriate
81288-MLH1 promoter methylation analysis
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
BRMLH | MLH1 Hypermethylation/BRAF Mutation | 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.
|
---|---|---|
53223 | Result Summary | 50397-9 |
53224 | Result | 82939-0 |
53225 | Interpretation | 69047-9 |
53226 | Specimen | 31208-2 |
53227 | Source | 31208-2 |
53228 | Tissue ID | 80398-1 |
54921 | BRAF Analysis | No LOINC Needed |
54440 | MLH1 Hypermethylation Analysis | No LOINC Needed |
53229 | Released By | 18771-6 |
55139 | Method | 85069-3 |
621822 | Disclaimer | 62364-5 |
Change Type | Effective Date |
---|---|
File Definition - Result ID | 2024-10-31 |