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HelpTest Code IHC Mismatch Repair (MMR) Protein Immunohistochemistry Only, Tumor
Useful For
Evaluating tumor tissue to identify patients at risk for having hereditary nonpolyposis colon cancer/Lynch syndrome
Additional Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| MLH1I | MLH-1, Immunostain | No, (Bill only) | Yes |
| MSH2I | MSH-2, Immunostain | No, (Bill only) | Yes |
| MSH6I | MSH-6, Immunostain | No, (Bill only) | Yes |
| PMS2I | PMS-2, Immunostain | No, (Bill only) | Yes |
Testing Algorithm
When this test is ordered, MLH1, MSH2, MSH6, and PMS2 stains will always be performed at an additional charge.
For more information see Lynch Syndrome Testing Algorithm.
Special Instructions
Method Name
Immunohistochemistry (IHC)
Reporting Name
MMR Protein, IHC Only, TumorSpecimen Type
VariesNecessary Information
Pathology report (final or preliminary) at minimum containing the following information must accompany specimen for testing to be performed:
1. Patient name
2. Block number-must be on all blocks, slides, and paperwork (can be handwritten on the paperwork)
3. Tissue collection date
4. Source of the tissue
Specimen Required
Tumor tissue is required.
Preferred:
Specimen Type: Tissue block
Collection Instructions: Submit formalin-fixed, paraffin-embedded tissue block.
Acceptable:
Specimen Type: Tissue slide
Slides: 1 Hematoxylin and eosin stained and 10 unstained
Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 10 unstained, nonbaked slides (5-micron-thick sections) of tumor tissue.
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Ambient (preferred) | ||
| Refrigerated | |||
Reference Values
An interpretive report will be provided.
Interpretation
The interpretation of molecular biomarker analysis includes an overview of the results and the associated diagnostic, prognostic, and therapeutic implications.
Clinical Reference
1. Baudhuin LM, Burgart LJ, Lentovich O, Thibodeau SN. Use of microsatellite instability and immunohistochemistry testing for the identification of individuals at risk for Lynch Syndrome. Fam Cancer. 2005;4(3):255-265. doi: 10.1007/s10689-004-1447-6
2. Shia J, Klimstra DS, Nafa K, et al. Value of immunohistochemical detection of DNA mismatch repair proteins in predicting germline mutation in hereditary colorectal neoplasms. Am J Surg Pathol. 2005;29(1):96-104
3. Idos G, Valle L. Lynch syndrome. In: Adam MP, Feldman J, Mirzaa GM, et al, eds. GeneReviews (Internet). University of Washington, Seattle; 2004. Updated February 2, 2021. Accessed December 5, 2023. Available at www.ncbi.nlm.nih.gov/books/NBK1211/
Day(s) Performed
Varies
Report Available
5 to 8 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
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.CPT Code Information
88341 MLH1, MLH2, or MLH6 (if appropriate)
88342 PMS2 (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| IHC | MMR Protein, IHC Only, Tumor | In Process |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 53258 | Result Summary | 50397-9 |
| 53259 | Result | In Process |
| 54443 | Interpretation | 59465-5 |
| 53260 | Specimen | 31208-2 |
| 53261 | Source | 31208-2 |
| 54444 | Tissue ID | 80398-1 |
| 53262 | MLH1 IHC | 81691-8 |
| 53263 | MSH2 IHC | 81692-6 |
| 53264 | MSH6 IHC | 81693-4 |
| 53265 | PMS2 IHC | 81694-2 |
| 53266 | Released By | 18771-6 |
Forms
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.