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Updated: Aug 16, 2026
Validated Immunochemical Assay for Comprehensive Determination of the Human Epidermal Growth Factor Receptor 2 Released from and Bound to Cells
Published on: May 9, 2025
Quantitative determination of nuclear and cytoplasmic epidermal growth factor receptor expression in oropharyngeal
Amanda Psyrri1, Ziwei Yu, Paul M Weinberger
1Department of Medical Oncology, Yale University School of Medicine, New Haven, Connecticut, USA.
Background:
Several lines of evidence support the epidermal growth factor receptor (EGFR) as a molecular target for therapy in head and neck squamous cell carcinomas (HNSCC). Determination of tumor EGFR levels by conventional immunohistochemistry has not always predicted antitumor efficacy. Quantitative assays may provide more accurate assessment of the level of EGFR receptor in the tumor, which may thus provide more reliable prognostic and predictive information. We studied the prognostic value of quantitative assessment of EGFR in oropharyngeal squamous cell cancers treated with radiotherapy.
Experimental Design:
We studied EGFR protein expression on a tissue microarray composed of 95 oropharyngeal cancer cases using an in situ molecular-based method of quantitative assessment of protein expression (AQUA) and correlated those with clinical and pathologic data. Automated, quantitative analysis uses cytokeratin to define pixels as cancer (tumor mask) within the array spot and measures intensity of EGFR expression using a Cy5-conjugated antibody within the mask. A continuous index score is generated, which is directly proportional to the number of molecules per unit area, and cases were defined as high expressing if they were above the median expression level.
Results:
The mean follow-up time for survivors was 44.9 months, and for the entire cohort was 34.8 months. Patients with high tumor EGFR expression levels had a local recurrence rate of 58% compared with 17% for patients with low EGFR tumor expression (P < 0.01). Similarly, patients with high nuclear EGFR expression had a local recurrence rate of 54% compared with 21% for patients with low EGFR nuclear expression (P < 0.05). Additionally, patients with high tumor and nuclear EGFR levels had inferior disease-free survival compared with low expressors (19% versus 43% and 19% versus 45%, respectively. P < 0.05 for each). In multivariate analysis adjusting for well-characterized prognostic variables, high tumor and nuclear EGFR expression levels retained their prognostic significance.
Conclusion:
The AQUA system provides a continuous measurement of EGFR on paraffin-embedded tissue and was able to reveal the association between EGFR expression and outcome expected from the biological role of EGFR. In the future, EGFR AQUA score may be useful in predicting response to EGFR-targeted therapies.
Insights
Quantitative assessment of epidermal growth factor receptor (EGFR) in oropharyngeal cancers revealed that high EGFR levels correlate with increased recurrence rates and poorer survival. This EGFR measurement may predict treatment response.
Area of Science:
- Oncology
- Molecular Biology
- Biomarker Research
Background:
- Epidermal growth factor receptor (EGFR) is a potential therapeutic target in head and neck squamous cell carcinomas (HNSCC).
- Conventional immunohistochemistry for EGFR levels has shown limitations in predicting treatment efficacy.
- Quantitative assays may offer more accurate prognostic and predictive information for EGFR in tumors.
Purpose of the Study:
- To evaluate the prognostic significance of quantitatively assessed EGFR levels in oropharyngeal squamous cell cancers treated with radiotherapy.
- To determine if quantitative EGFR measurement can provide more reliable prognostic information than conventional methods.
Main Methods:
- Utilized a tissue microarray of 95 oropharyngeal cancer cases.
- Employed the AQUA method for in situ quantitative assessment of EGFR protein expression.
- Correlated quantitative EGFR levels (tumor and nuclear) with clinical and pathological data, defining high expression as above the median.
Main Results:
- Patients with high tumor EGFR expression had significantly higher local recurrence rates (58% vs. 17%) and inferior disease-free survival compared to low expressors.
- High nuclear EGFR expression also correlated with increased local recurrence (54% vs. 21%) and poorer survival.
- Quantitative EGFR levels retained prognostic significance in multivariate analysis.
Conclusions:
- The AQUA system provides a reliable, continuous measurement of EGFR expression in paraffin-embedded tissues.
- EGFR expression levels quantitatively assessed by AQUA are associated with patient outcomes in oropharyngeal cancer.
- Future applications of EGFR AQUA scoring may aid in predicting response to EGFR-targeted therapies.
