COL4A1 Methylation Detection for Colorectal Cancer Screening
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Solution Overview
Problem
Current screening tests for colorectal cancer, such as feces DNA tests, face challenges in extracting human DNA from complex feces samples and selecting markers with high sensitivity and specificity, as existing markers like vimentin and SFRP1 show reduced sensitivity when used in fecal specimens compared to tissue samples.
Innovation Solution
The use of the COL4A1 gene as a tumor marker, with specific capture sequences, primers, and probes for methylation detection, enhances sensitivity and specificity in detecting colorectal cancer in fecal specimens, employing methods like methylation-specific PCR (MSP) and quantitative methylation-specific PCR (qMSP) to analyze methylation levels in the COL4A1 gene's promoter region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing markers like vimentin and SFRP1 are used for detection, then detection can be performed, but sensitivity is significantly reduced when used in fecal specimens compared to tissue samples
Solution Approach 1:
The patent changes the detection target from protein expression (western blot, immunohistochemistry) to DNA methylation status (bisulfite sequencing, methylation-specific PCR). This parameter change from detecting protein levels to detecting epigenetic modifications resolves the sensitivity loss in fecal specimens, as DNA methylation markers maintain high sensitivity across tissue and fecal samples unlike protein markers
2Ease of operation
If feces DNA test is used for screening, then non-invasive detection is achieved, but extraction of human DNA from complex feces samples with many inhibitors and bacterial DNA is difficult
Solution Approach 1:
The patent extracts and isolates specifically methylated human DNA sequences from the complex fecal DNA mixture using targeted approaches. By focusing on detecting only the methylated COL4A1 gene sequences rather than analyzing total DNA, the method effectively extracts the relevant diagnostic signal from the complex background of bacterial DNA and inhibitors
Solution Approach 2:
The patent uses methylation-specific primers and probes as intermediaries to selectively bind and detect human tumor DNA sequences in the presence of bacterial DNA and inhibitors. These specific molecular intermediaries enable selective amplification and detection of target sequences without being affected by the complex fecal matrix
3Reliability
If more markers are tested to improve detection accuracy, then detection rate increases, but the complexity of the detection system increases
Solution Approach 1:
The patent makes the single COL4A1 methylation marker perform multiple functions by detecting different methylation sites and using multiple analytical methods (bisulfite sequencing, MSP, qMSP). This multi-functional approach allows one marker to provide comprehensive diagnostic information, replacing the need for multiple different markers and reducing overall system complexity while maintaining high detection accuracy
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 COL4A1 gene-based detection reagent achieves high sensitivity (83.8%) and specificity (95.2%) in detecting colorectal cancer in fecal specimens, outperforming existing markers and allowing for reliable non-invasive diagnosis, with the potential for early detection of colorectal cancer through methylation analysis.
Implementation Method 1
employing methods like methylation-specific PCR (MSP) and quantitative methylation-specific PCR (qMSP) to analyze methylation levels in the COL4A1 gene's promoter region
Data Source
AI summary
The present invention relates to the technical field of biology. Disclosed are a tumor marker, a methylation detection reagent, a kit and application thereof. Disclosed in the present invention is that: a colorectal cancer specimen can be distinguished from a fecal specimen of a normal person by detection a methylation level of COL4A1 gene promoter region. The present invention relates to detecting colorectal cancer by using the methylation detection reagent of the gene.