What is MSI and IHC testing?
Lynch Syndrome MSI plus IHC is a tumor screening test for all newly diagnosed colorectal cancer patients to identify patients who may have an inherited form of colorectal cancer (Hereditary Nonpolyposis Colon Cancer or Lynch Syndrome).
Why MSI testing is done?
MSI screening is used to see if the Lynch syndrome genes are working properly. Microsatellites are regions of repeated DNA that change in length (show instability) when mismatch repair is not working properly.
How do you test for microsatellite instability?
Microsatellite instability testing is used to identify tumors caused by defective MMR by comparing the number of nucleotide repeats in a panel of microsatellite markers in normal tissue with the number from tumor tissue from the same individual.
What is MMR IHC testing?
Indications for use: The VENTANA MMR IHC Panel is a qualitative immunohistochemistry (IHC) test intended for use in the light microscopic assessment of mismatch repair (MMR) proteins (MLH1, PMS2, MSH2, and MSH6) and BRAF V600E proteins in formalin-fixed, paraffin-embedded colorectal cancer (CRC) tissue sections.
How do I read MSI IHC?
It is defined as high frequency of microsatellite instability (MSI-H) when two or more of the five markers in the tumor DNA were positive. If only one marker was positive, the tumor is termed as low frequency of MSI (MSI-L). And MSS is determined when all of the five markers were negative [7].
What is microsatellite instability status?
Microsatellite instability (MSI) is the condition of genetic hypermutability (predisposition to mutation) that results from impaired DNA mismatch repair (MMR). The presence of MSI represents phenotypic evidence that MMR is not functioning normally.
How is MSI diagnosed?
To detect MSI, the amplified fragments from the tumor and matched normal samples are measured and compared. The amplified fragments are separated by size using capillary electrophoresis, and the fluorescent labelling allows them to be separated by the color of the fluorescent tag.
What is IHC testing?
IHC, or ImmunoHistoChemistry, is a special staining process performed on fresh or frozen breast cancer tissue removed during biopsy. IHC is used to show whether or not the cancer cells have HER2 receptors and/or hormone receptors on their surface. This information plays a critical role in treatment planning.
Is IHC genetic testing?
IHC screening looks to see if certain proteins are absent in the tumor sample, indicating that one of the Lynch syndrome genes might not be working properly….Immunohistochemistry screening (IHC)
| Test Result | What it means | Next Step |
|---|---|---|
| Absent MSH2 and MSH6 proteins | You are likely to have Lynch syndrome | Genetic counseling and testing |
What does microsatellite instability mean?
Microsatellite instability (MSI) is a unique molecular alteration and hyper-mutable phenotype, which is the result of a defective DNA mismatch repair (MMR) system, and can be defined as the presence of alternate sized repetitive DNA sequences which are not present in the corresponding germ line DNA.
What cancers are associated with Lynch syndrome?
Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), is the most common cause of hereditary colorectal (colon) cancer.
- Uterine (endometrial),
- Stomach,
- Liver,
- Kidney,
- Brain, and.
- Certain types of skin cancers.