Immunohistochemistry Microsatellite Instability Panel Test
Understanding Microsatellite Instability Testing
The Immunohistochemistry Microsatellite Instability Panel represents a groundbreaking advancement in cancer diagnostics, specifically designed to detect abnormalities in DNA mismatch repair proteins. This sophisticated test evaluates four essential proteins—MLH1, MSH2, MSH6, and PMS2—that play critical roles in maintaining genomic stability and preventing cancer development.
What is Microsatellite Instability?
Microsatellite instability occurs when the DNA mismatch repair system fails to function properly, leading to errors in DNA replication. These errors accumulate in repetitive DNA sequences called microsatellites, creating instability that can drive cancer progression. The Immunohistochemistry MSI Panel directly assesses the functionality of the mismatch repair system by examining protein expression patterns in tumor tissue samples.
What the Test Measures and Detects
This comprehensive panel specifically evaluates the presence and distribution of four crucial DNA mismatch repair proteins:
- MLH1 Protein: Assesses MutL homolog 1 expression, a key component in DNA mismatch recognition
- MSH2 Protein: Evaluates MutS homolog 2, essential for initiating DNA repair processes
- MSH6 Protein: Tests MutS homolog 6, which partners with MSH2 in mismatch recognition
- PMS2 Protein: Examines postmeiotic segregation increased 2, working with MLH1 in repair complex formation
The test detects abnormal protein expression patterns that indicate defective DNA mismatch repair, which is strongly associated with Lynch syndrome and various sporadic cancers. Loss of any of these proteins suggests microsatellite instability and has significant implications for cancer treatment and prognosis.
Who Should Consider This Test
This specialized testing is recommended for individuals with specific clinical presentations and risk factors:
Clinical Indications
- Patients diagnosed with colorectal cancer, particularly those under age 50
- Individuals with endometrial cancer and personal or family history of Lynch syndrome-associated cancers
- Patients with multiple primary cancers involving colorectal, endometrial, gastric, ovarian, or other Lynch-related malignancies
- Those with strong family history of colorectal, endometrial, or other gastrointestinal cancers
- Patients being considered for immunotherapy, as MSI status predicts response to immune checkpoint inhibitors
- Individuals meeting Amsterdam criteria or revised Bethesda guidelines for Lynch syndrome testing
Symptoms and Risk Factors
- Unexplained weight loss and gastrointestinal symptoms in younger patients
- Multiple primary cancers in the same individual
- Family history spanning multiple generations with early-onset cancers
- Personal history of colorectal cancer with specific histopathological features
- Synchronous or metachronous colorectal cancers
Benefits of Immunohistochemistry MSI Testing
This advanced diagnostic approach offers numerous advantages for cancer patients and their healthcare providers:
Clinical Benefits
- Accurate Lynch Syndrome Identification: Helps identify hereditary cancer syndromes for proper family screening and risk management
- Treatment Guidance: MSI-high status predicts excellent response to immunotherapy with checkpoint inhibitors
- Prognostic Information: Provides valuable insights into cancer behavior and expected outcomes
- Cost-Effective Screening: Serves as an initial screening tool before more expensive genetic testing
- Therapeutic Decision Support: Guides selection of appropriate chemotherapy and targeted therapies
Patient-Centered Advantages
- Enables personalized cancer treatment plans based on individual tumor characteristics
- Facilitates family cancer risk assessment and preventive strategies
- Provides clarity on cancer inheritance patterns for genetic counseling
- Supports informed decision-making about treatment options and clinical trials
Understanding Your Test Results
Interpreting Immunohistochemistry MSI Panel results requires specialized expertise, but general guidance includes:
Normal Results
Normal nuclear staining for all four proteins (MLH1, MSH2, MSH6, PMS2) indicates intact DNA mismatch repair function. This suggests microsatellite stability and typically correlates with standard treatment responses.
Abnormal Results
Loss of protein expression in any of the four markers indicates defective DNA mismatch repair:
- Isolated MLH1/PMS2 Loss: Often associated with sporadic cancers due to MLH1 promoter hypermethylation
- Isolated MSH2/MSH6 Loss: Highly suggestive of Lynch syndrome, particularly with MSH2 mutations
- Isolated MSH6 Loss: May indicate Lynch syndrome with MSH6 mutations
- Isolated PMS2 Loss: Suggests Lynch syndrome with PMS2 mutations
Clinical Implications
Abnormal results typically lead to additional testing, including BRAF mutation analysis and MLH1 promoter methylation studies to distinguish between sporadic and hereditary cases. MSI-high status often qualifies patients for immunotherapy regardless of cancer type, following FDA approvals.
Test Pricing and Availability
| Test Component | Regular Price | Discount Price |
|---|---|---|
| Immunohistochemistry Microsatellite Instability Panel | $280 USD | $250 USD |
Turnaround Time
- Sample Acceptance: Daily by 6 PM
- Report for Block: 5 days
- Tissue Biopsy: 5 days
- Tissue Large Complex: 7 days
Sample Requirements
Submit tumor tissue in 10% formal-saline OR formalin-fixed paraffin-embedded block. Ship at room temperature. Essential documentation includes:
- Copy of Histopathology report
- Site of biopsy specification
- Complete clinical history
Nationwide Testing Availability
We maintain comprehensive testing facilities across the United States, with branches strategically located in all major metropolitan areas including New York, Los Angeles, Chicago, Houston, Phoenix, Philadelphia, San Antonio, San Diego, Dallas, San Jose, and numerous other cities. Our nationwide network ensures convenient access to this essential cancer diagnostic testing regardless of your location.
Book Your Test Today
Take the first step toward personalized cancer care and accurate diagnosis. Our experienced team of oncologists and pathologists are ready to provide you with comprehensive testing and expert interpretation of results.
Call or WhatsApp us today at +1(267) 388-9828 to schedule your Immunohistochemistry Microsatellite Instability Panel test. Our dedicated patient coordinators will guide you through the testing process, answer your questions, and ensure you receive the highest quality cancer diagnostic services available.
Early detection and accurate characterization of microsatellite instability can significantly impact treatment decisions and outcomes. Don’t delay—secure your appointment now for this vital cancer diagnostic assessment.
