Cell-Free DNA MSI Detection Using Site-Specific Locus Thresholds
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Solution Overview
Problem
Current methods for detecting microsatellite instability (MSI) in cell-free DNA (cfDNA) samples are underdeveloped, and the impact of variable tumor shedding on MSI detection has not been adequately addressed.
Innovation Solution
A method involving quantifying repeat lengths at microsatellite loci, generating site scores, comparing against trained thresholds, and classifying MSI status using probabilistic log likelihood-based scores to determine MSI status, which includes identifying customized therapies based on MSI results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PCR-based MSI assessment methods are used, then measurement precision is improved, but device complexity and ease of operation worsen due to requiring complex laboratory procedures
Solution Approach 1:
The patent replaces complex mechanical laboratory procedures (PCR-based assessment requiring specialized equipment and facilities) with computational methods that analyze existing sequencing data through probabilistic algorithms and bioinformatic pipelines, thereby maintaining measurement precision while eliminating device complexity
Solution Approach 2:
The patent introduces computational algorithms and bioinformatic analysis pipelines as intermediaries between raw sequencing data and MSI status determination, serving as a bridge that translates complex biological data into clinically actionable results without requiring direct complex laboratory procedures at the point of care
2Ease of operation
If computational methods are used for MSI detection, then ease of operation is improved, but measurement precision worsens due to lack of validation
Solution Approach 1:
The patent implements feedback mechanisms through iterative optimization of computational algorithms, where analysis results are continuously refined by comparing against known standards and adjusting parameters to maximize concordance with PCR-based methods, thereby ensuring measurement precision while maintaining ease of operation
Solution Approach 2:
The patent performs preliminary validation and optimization of computational algorithms using training datasets before clinical application, establishing performance benchmarks and refining methods in advance to ensure measurement precision is achieved before the methods are deployed for routine MSI detection
3Loss of information
If comprehensive genomic profiling is performed, then information completeness is improved, but loss of time worsens due to extended analysis requirements
Solution Approach 1:
The patent extracts and prioritizes specific microsatellite loci and genomic regions that are most critical for MSI detection from comprehensive genomic data, separating essential information from supplementary data to deliver timely MSI results while maintaining information completeness for comprehensive profiling
Solution Approach 2:
The patent segments the comprehensive genomic analysis into distinct analytical components, allowing parallel processing of different genomic regions and simultaneous execution of multiple analytical tasks, thereby reducing overall analysis time while preserving complete genomic information assessment
Data Source
AI summary
Provided herein are methods for determining the microsatellite instability status of samples. In one aspect, the methods include quantifying a number of different repeat lengths present at each of a plurality of microsatellite loci from sequence information to generate a site score for each of the plurality of the microsatellite loci. The methods also include comparing the site score of a given microsatellite locus to a site specific trained threshold for the given microsatellite locus for each of the plurality of the microsatellite loci and calling the given microsatellite locus as being unstable when the site score of the given microsatellite locus exceeds the site specific trained threshold for the given microsatellite locus to generate a microsatellite instability score, which includes a number of unstable microsatellite loci from the plurality of the microsatellite loci.