Related Experiment Videos
Diagnostic microsatellite instability: definition and correlation with mismatch repair protein expression
W Dietmaier1, S Wallinger, T Bocker
1Institute of Pathology, University of Regensburg, Germany.
Cancer Research
|November 14, 1997
Summary
Microsatellite instability (MSI) is key in colorectal cancer. This study recommends a standardized panel of 10 markers for reliable MSI diagnosis, crucial for screening and prognosis.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- Microsatellite instability (MSI) is a hallmark of colorectal carcinogenesis, linked to hereditary nonpolyposis colorectal cancer (HNPCC) and sporadic tumors.
- MSI status is valuable for HNPCC screening and colorectal cancer prognosis, but diagnostic reliability remains debated.
Purpose of the Study:
- To evaluate the reliability of MSI diagnosis using a panel of 31 microsatellite markers.
- To establish standardized criteria for MSI classification and diagnostic analysis.
Main Methods:
- Analysis of 58 primary colorectal tumors using 31 microsatellite markers.
- Immunohistochemical study of hMSH2 and hMLH1 mismatch repair protein expression.
- Assessment of reproducibility, sensitivity, and specificity of MSI determination.
Main Results:
- MSI diagnosis reliability depends on marker repeat type; MSI can be classified as high (>20%), low (<10%), or stable (0%).
- High MSI tumors often showed loss of hMSH2 or hMLH1 protein expression, unlike low MSI or stable tumors.
- A panel of 10 microsatellites and a 40% instability threshold are recommended for diagnostic MSI analysis.
Conclusions:
- Standardized MSI analysis using a defined marker panel enhances diagnostic accuracy for colorectal cancer.
- Consistent MSI assessment aids in identifying HNPCC and predicting tumor prognosis.