Whole Blood

Lavender top tube 3 mL (EDTA)

Yellow top tube (ACD solution A)

1 mL whole blood in a lavender-top (EDTA) tube(s) or a yellow-top (ACD) tube(s).

5 days upon receipt at the reference laboratory

An interpretive report will be provided.

An interpretive report will include specimen information, pedigree (when appropriate), assay information, and whether the results are consistent with a diagnosis of defective mismatch repair-related hereditary nonpolyposis colorectal cancer.

Mutation carriers face a significantly increased risk of colorectal cancer, as well as increased risk for cancers of the endometrium, kidneys, bladder, stomach, small bowel, pancreas, and ovaries.

Please print, complete and submit the following forms to the lab, with the specimen and the A-1a Miscellaneous Request: Molecular Genetics- Inherited Cancer Syndromes Patient Information Sheet and the Informed Consent for Genetic Testing from the Mayo Medical Laboratories.

Useful for an alternative approach to establishing a diagnosis of mismatch repair-related Hereditary nonpolyposis colorectal cancer (HNPCC) (Lynch syndrome).

Detection of mutations in hMLH1 and hMSH2, the 2 most commonly affected genes in HNPCC, when microsatellite instability and immunohistochemistry tumor testing is not possible and when a diagnosis of HNPCC is suspected
Cautions:
A small percentage of individuals who are carriers or have a diagnosis of HNPCC and/or involvement of hMLH1 or hMSH2 by immunohistochemistrymay have a mutation that is not identified by this method (eg, promoter mutations, deep intronic alterations). The absence of a mutation(s), therefore, does not eliminate the possibility of positive carrier status or the diagnosis of hereditary nonpolyposis colorectal cancer. For carrier testing, it is important to first document the presence of an hMLH1 or hMSH2 gene mutation in an affected family member.

In some cases, DNA alterations of undetermined significance may be identified.

Rare polymorphisms exist that could lead to false-negative or false- positive results. If results obtained do not match the clinical findings, additional testing should be considered.

A previous bone marrow transplant from an allogenic donor will interfere with testing. Call Mayo Medical Laboratories for instructions for testing patients who have received a bone marrow transplant.

Test results should be interpreted in the context of clinical findings, family history, and other laboratory data. Errors in our interpretation of results may occur if information given is inaccurate or incomplete.

We strongly recommend that patients undergoing predictive testing receive genetic counseling both prior to testing and after results are available.

In addition to disease-related probes, the multiplex ligation-dependent probe amplification technique utilizes probes localized to other chromosomal regions as internal controls. In certain circumstances, these control probes may detect other diseases or conditions for which this test was not specifically intended. Results of the control probes are not normally reported. However, in cases where clinically relevant information is identified, the ordering physician will be informed of the result and provided with recommendations for any appropriate follow- up testing.

DNA sequence analysis is performed to test for the presence of a mutation in all 19 exons of the hMLH1 gene and 16 exons of the hMSH2 gene. Additionally, gene dosage analysis (multiplex ligation-dependent probe amplification or Southern blot analysis) is used to test for the presence of large deletions, duplications, and other genomic rearrangements in these genes.

"MLH1/MSH2 Mutation Screen"
83891 x1, 83892 x7, 83900 x5, 83901 x21, 83909 x70, 83898 x2
  and 83894 x7

"MLH1/MSH2 Large Deletion/Duplication, MLPA"
83900 x1, 83914 x39, 83909 x1