Microsatellite Instability (MSI)/HNPCC/Lynch Syndrome, PCR

The Microsatellite Instability (MSI) test detects the stability of specific genetic markers called microsatellites. These markers help assess for abnormalities in DNA replication and repair, indicating the presence of microsatellite instability. MSI is associated with Lynch syndrome, a hereditary condition that increases the risk of certain cancers.

This test is primarily done to:

• Screen for Lynch syndrome, a hereditary condition associated with an increased risk of colorectal and other cancers
• Identify candidates for targeted immune therapy using Pembrolizumab, a drug used in treating certain advanced cancers.
• Assist in assessing the effectiveness of treatment for Lynch syndrome-related tumors.

Your doctor may recommend the Microsatellite Instability (MSI) test if you:

• Have a personal or family history of Lynch syndrome or related cancers.
• Present with symptoms or tumors suggestive of Lynch syndrome.
• Require evaluation for targeted immune therapy candidacy using Pembrolizumab.

Possible implications of abnormal results include:

• Higher risk of Lynch syndrome-associated cancers
• Potential eligibility for targeted immune therapy with Pembrolizumab

Discuss the results with your doctor for appropriate diagnosis and further management

• A small biopsy may be taken from the tumor site and a blood sample collected by an oncologist in a clinic or hospital setting
• The samples will undergo processing and analysis to detect microsatellite instability using PCR analysis.
• Results are typically reported within 10 days.

• Provide your clinical history and any relevant histopathology reports.
• If tissue samples are required, consult your healthcare provider for specific instructions.

Alongside the Microsatellite Instability (MSI) test, your doctor may recommend:

• Immunohistochemistry (IHC): To assess protein expression levels to further diagnose Lynch syndrome or related cancers
• Genetic testing: To identify specific gene mutations associated with Lynch syndrome or hereditary conditions

• MSI test
• Molecular pathology test for Lynch syndrome
• Genetic testing for microsatellite instability

Lynch Syndrome, also known as hereditary nonpolyposis colorectal cancer (HNPCC), is an inherited condition that increases the risk of certain cancers, especially in the colon and rectum. It is caused by specific genetic mutations that affect DNA replication and repair mechanisms. Early detection through genetic testing helps manage the risk and implement appropriate preventive measures.