EGFR Assay Using Multiplex RT-PCR for Sensitive FFPE Detection
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Solution Overview
Problem
Current methods for detecting and quantifying EGFR and EGFRvIII in cancer tumors are not sufficiently sensitive or specific, particularly in formalin-fixed paraffin-embedded samples, and do not provide adequate diagnostic and prognostic tools for oncology.
Innovation Solution
A novel RT-PCR assay format using specific primers and probes targeting exon junctions of EGFR and EGFRvIII mRNA, allowing for single-well multiplex detection and quantification of EGFRvIII and total EGFR expression, with optional endogenous control RNA, suitable for FFPE samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional RT-PCR assays are used for detecting EGFR and EGFRvIII, then detection can be performed, but sensitivity and specificity are insufficient particularly in FFPE samples
Solution Approach 1:
The assay segments the detection process into separate well-defined stages: reverse transcription of RNA to cDNA, followed by quantitative PCR amplification. This segmentation allows optimization of each step independently, improving overall sensitivity and specificity for detecting EGFR and EGFRvIII in challenging FFPE samples
Solution Approach 2:
The patent introduces an intermediary conversion step where RNA is first reverse transcribed to cDNA before PCR amplification. This intermediary step (reverse transcription) enables the detection of RNA expression levels while improving the reliability of the assay in FFPE samples by converting labile RNA into more stable cDNA
2Productivity
If multiple targets (EGFRvIII and total EGFR) are detected separately, then each can be analyzed, but the process requires multiple wells and is inefficient
Solution Approach 1:
The patent merges the detection of multiple targets (EGFRvIII and total EGFR) into a single-well multiplex assay. By combining primers and probes for different targets in one reaction well, the assay achieves simultaneous detection and quantification of multiple EGFR variants, improving productivity while managing complexity through careful primer/probe design
Solution Approach 2:
The assay design provides universal detection capability for both EGFRvIII mutant and total EGFR (wild-type) using a single multiplex system. The universal nature of this single-well approach allows it to function for multiple diagnostic purposes: detecting mutation presence, quantifying expression levels, and assessing tumor heterogeneity
3Measurement precision
If conventional PCR assays are used, then amplification can be performed, but the assays lack the sensitivity required for accurate quantification of low-abundance transcripts
Solution Approach 1:
The patent implements continuous monitoring of amplification in real-time during the PCR process, rather than endpoint detection. This continuous measurement approach allows accurate quantification of low-abundance transcripts by tracking the exponential amplification phase, improving measurement precision without sacrificing amplification efficiency
Solution Approach 2:
The patent replaces conventional endpoint PCR detection methods with real-time fluorescent detection. This substitution uses optical detection (fluorescence) during the amplification process itself, enabling sensitive quantification of low-abundance transcripts while maintaining efficient amplification through continuous monitoring rather than post-amplification analysis
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
Provides sensitive and specific detection and quantification of EGFRvIII and total EGFR mRNA, enabling accurate diagnostic and prognostic tools for cancer treatment, including the use of anti-EGFR therapeutic agents based on expression levels.
Implementation Method 1
reverse transcribing total EGFR mRNA to provide total EGFR cDNA and reverse transcribing EGFRvIII mRNA to provide a EGFRvIII cDNA
Implementation Method 2
amplifying the total EGFR cDNA to provide a total EGFR amplicon and amplifying the EGFRvIII cDNA to provide a EGFRvIII amplicon
Implementation Method 3
a detectably labeled probe to detect EGFRvIII RNA; a novel design for a labeled oligonucleotide probe to detect total EGFR RNA
Data Source
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AI summary
Provided herein is technology relating to detecting molecular markers relevant to cancer and particularly, but not exclusively, to methods and compositions for quantifying and/or detecting EGFR mRNA and/or EGFRvIII mRNA in biological samples.