Molecular Genetic Microsatellite Instability Index - NGS
Test Code
MOG37
Also Known As
No data available
Test Parameters Included
No data available
Department
MOLECULAR GENETICS
Methodology
NGS (Next-Generation Sequencing)
The primary methodology for detecting Microsatellite Instability (MSI) in this context is Next-Generation Sequencing (NGS). NGS-based MSI analysis offers several advantages over traditional PCR-based methods, particularly its ability to assess a much larger number of microsatellite markers across the genome simultaneously and provide a quantitative MSI index. The process involves:
* DNA Extraction: From both the tumor tissue (FFPE) and a matched normal tissue sample (e.g., blood, if available, for comparison).
* Targeted Amplification/Library Preparation: Specific regions of DNA containing numerous microsatellite markers are amplified. NGS panels designed for MSI analysis typically include a large number of mononucleotide and dinucleotide repeat markers (often hundreds or thousands) distributed across the genome, rather than just the traditional 5-7 markers used in PCR-based methods.
* Sequencing: The amplified DNA fragments are sequenced using NGS platforms.
* Bioinformatic Analysis: Sophisticated software pipelines compare the lengths of microsatellite repeats in the tumor DNA to those in the matched normal DNA. Instability is indicated by changes in the length of these repeats (expansions or contractions) in the tumor. The software then calculates an MSI index or percentage of unstable markers.
NGS provides a quantitative assessment of MSI, allowing for a more nuanced classification (e.g., MSI-High, MSI-Low, MSS) and potentially higher sensitivity and specificity than traditional methods, especially when tumor content is low.
Sample Required
FFPE TISSUE > 10% CANCER
(Formalin-Fixed Paraffin-Embedded (FFPE) tumor tissue is the required sample type. It is crucial that the tissue block or scrolls submitted contain greater than 10% cancer cells to ensure sufficient tumor DNA for accurate analysis. Ideally, a matched normal sample (e.g., peripheral blood in EDTA) is also provided for comparison, though some NGS panels can infer MSI without a matched normal by comparing against a database of germline microsatellite lengths.)
Preparation
Preparation for this test primarily involves proper sample collection and handling of the FFPE tissue. * Sample Type: Formalin-Fixed Paraffin-Embedded (FFPE) tumor tissue block or scrolls. * Tumor Con... Read more
Schedule Report
30 Days
Emergency Report
Yes
Frequently Asked Questions
No data available
Test Description
- High-end laboratory & medical equipment.
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