HER2 Protein Quantitation in Breast Cancer via Mass Spectrometry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for measuring HER2 protein expression in breast cancer samples are subjective and lack reproducibility, particularly for HER2 2+ equivocal cases, as they rely on Immunohistochemistry (IHC) and Fluorescent in situ Hybridization (FISH), which are qualitative and expensive, respectively.
Innovation Solution
A method using mass spectrometry, specifically Multiple Reaction Monitoring (MRM)-MS, to quantify HER2 protein expression levels in Formalin-Fixed, Paraffin-Embedded (FFPE) tissue samples, allowing for accurate determination of HER2 scores by correlating normalized peptide amounts with specific scores (0, 1+, 2+FISH-, 2+FISH+, or 3+) through the use of normalization factors like JAM1 peptides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If Immunohistochemistry (IHC) is used to measure HER2 protein expression, then the method is simple and widely applicable, but the measurement is subjective and lacks reproducibility due to visual assessment by pathologists
Solution Approach 1:
The patent replaces the manual visual assessment system (mechanical/optical microscopy with human interpretation) with an automated mass spectrometry system. The MRM-MS method uses mass spectrometric detection to quantify HER2 peptides, eliminating subjective visual assessment by pathologists while providing objective, reproducible quantitative measurements of HER2 protein expression levels.
2Measurement precision
If Fluorescent in situ Hybridization (FISH) is used to re-evaluate equivocal HER2 2+ cases, then the measurement accuracy is improved, but the cost and technical difficulty increase significantly
Solution Approach 1:
The patent extracts the quantification function from the complex FISH procedure by using mass spectrometry to directly measure HER2 protein levels. Instead of performing full FISH analysis on equivocal cases, the MRM-MS method extracts and quantifies specific HER2 peptides from tissue samples, providing accurate differentiation of equivocal cases without requiring the complex FISH workflow.
Solution Approach 2:
The patent introduces mass spectrometry as an intermediary method between IHC and FISH. Rather than proceeding directly to expensive and complex FISH for equivocal cases, the MRM-MS method serves as an intermediate quantitative assessment tool that can resolve equivocal cases more accurately than IHC while avoiding the complexity and cost of FISH.
3Reliability
If FISH is performed on all equivocal HER2 2+ cases, then the diagnostic accuracy is improved, but the cost and time consumption increase dramatically
Solution Approach 1:
The patent performs preliminary quantitative assessment using MRM-MS before committing to full FISH analysis. By pre-quantifying HER2 protein levels in equivocal cases using the faster, more accessible mass spectrometry method, the workflow identifies cases that clearly resolve without requiring subsequent FISH, thereby reducing overall time and cost while maintaining diagnostic accuracy for resolved cases.
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
This approach provides more accurate and reproducible HER2 scoring, distinguishing between 2+FISH- and 2+FISH+ groups, reducing the need for costly and time-consuming FISH tests, leading to improved diagnostic accuracy and customized therapy options while lowering socio-economic costs.
Implementation Method 1
determining an amount of a specific HER2 peptide fragment prepared from the breast cancer sample digested with a protease; and as a normalization factor, determining an amount of a peptide corresponding to SEQ ID NO: 3 from JAM1
Data Source
Figure 1
Figure 2
Figure 3A~3D
AI summary
The present application discloses a method for accurate quantification of a HER2 protein in a breast cancer tissue sample by mass spectrometry and a HER2 scoring based thereon. A method according to the present application is accurate and can make reproducible measurement compared to conventional methods. If possible, personalized therapy according to the method of the present application can prolong lives of the patients and exceptionally reduce the socioeconomic cost nationwide.