Digital PCR Microsatellite Panel for Breast Cancer MSI Screening
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Solution Overview
Problem
Current methods for detecting microsatellite instability (MSI) in breast cancer are inadequate, limiting access to immunotherapy for patients who could benefit from it due to low prevalence and lack of evidence supporting next-generation sequencing (NGS) use.
Innovation Solution
A droplet-based digital PCR assay targeting specific microsatellites (M1, M2, M3, M4) identified through whole-genome sequencing is developed and validated for breast cancer samples, allowing accurate determination of MSI status in tumor and circulating DNA, facilitating non-invasive screening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If next-generation sequencing (NGS) is used for MSI detection in breast cancer, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and focuses on detecting only the 4 specific microsatellite loci (M1-M4) that are most relevant for breast cancer MSI detection, rather than using comprehensive NGS to sequence entire genomes. This targeted approach maintains detection precision while dramatically reducing complexity by isolating only the essential genetic markers needed for clinical decision-making
Solution Approach 2:
The patent employs a simplified PCR-based assay that is more cost-effective and less complex than NGS, making MSI detection accessible for routine clinical use in breast cancer screening. The method uses standard laboratory equipment and reagents rather than expensive NGS platforms, enabling widespread adoption without requiring specialized facilities
2Measurement precision
If comprehensive NGS is used to interrogate dozens or hundreds of microsatellites, then measurement precision is improved, but loss of time and productivity are worsened
Solution Approach 1:
The patent identifies and extracts the 4 most informative microsatellite loci (M1-M4) from among dozens or hundreds of possible markers, creating a streamlined panel that maintains clinical accuracy while reducing assay time from days to hours. This focused approach eliminates unnecessary testing of loci that do not contribute significantly to diagnostic precision
Solution Approach 2:
The patent applies partial action by testing only the essential 4 microsatellite loci rather than performing exhaustive sequencing of all possible microsatellites. This selective approach provides sufficient diagnostic information for clinical decision-making while achieving rapid results that enable timely patient treatment
3Reliability
If MSI detection is performed in breast cancer patients with low prevalence, then reliability of immunotherapy selection is improved, but productivity and screening efficiency are worsened
Solution Approach 1:
The patent tailors the microsatellite panel specifically to breast cancer by selecting 4 loci (M1-M4) that have been validated for this cancer type, rather than using generic panels designed for colorectal or other cancers. This localized optimization ensures high reliability for breast cancer immunotherapy selection while maintaining efficient screening throughput
Solution Approach 2:
The patent implements a focused screening approach that tests only the 4 most relevant microsatellite loci in breast cancer patients, providing sufficient sensitivity and specificity to identify the small subset of patients who will benefit from immunotherapy while avoiding the resource-intensive comprehensive NGS approach
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method provides rapid, cost-effective identification of MSI status in breast cancer patients, enabling large-scale pre-screening for immunotherapy eligibility.
Implementation Method 1
detecting a mutation within a microsatellite sequence by subjecting said sample to a digital polymerase chain reaction
Data Source
Figure 1A~1B
Figure 1C
Figure 1C
AI summary
The present invention relates to a method for identifying a cancer patient presenting microsatellite unstable tumor who is likely to benefit from immunotherapy comprising detecting a mutation within a microsatellite sequence by subjecting said sample to a digital polymerase chain reaction. The present invention also encompasses an immune checkpoint inhibitor for use in the treatment of a cancer in a patient who is previously identified as likely benefit from an immunotherapy and a method for evaluating the therapeutic response of an immune checkpoint inhibitor in a patient having a cancer.