MLH1 Hypermethylation and BRAF Mutation Analysis, Tumor

Casandra

Casandra Test Code MC63339Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID BRMLHCPT Codes 81210, 81288, 88381

MLH1 Hypermethylation and BRAF Mutation Analysis, Tumor

Clinical Use

Use

This test is used as an adjunct in evaluating cases where colon tumors demonstrate microsatellite instability (MSI-H) and loss of MLH1 protein expression. It helps distinguish between somatic and germline events, particularly when performing expensive germline testing is considered. It is useful in cases where colon tumor from the same patient demonstrates MSI-H and loss of MLH1 protein expression and when negative MLH1 germline testing has been documented. The test is not a genetic test but helps stratify the risk for having an inherited cancer predisposition.

Special Instructions

This test is not recommended as a first-tier screening for Lynch syndrome. It should be ordered for colon tumors demonstrating loss of MLH1 protein expression. Pathology reports must accompany the specimen for testing. IHC stains may be required for optimizing the tissue area selected for testing, in cases of ambiguous or unusual results.

Limitations

The test is specifically developed for colon tumors and other tissues like endometrial tumors may have limited evaluation, performing only the MLH1 hypermethylation. Colon cancer may occur in Lynch syndrome families as sporadic events, therefore other family members should still be considered for evaluation in cases without BRAF V600E alteration and with MLH1 promoter hypermethylation.

Test Details

New York Approved