Increased epidermal growth factor receptor expression in metaplastic bronchial epithelium

Area of Science:

• Pulmonary Medicine
• Oncology
• Molecular Biology

Background:

• Epidermal growth factor receptor (EGFr) is elevated in non-small cell lung cancers.
• Squamous metaplasia in bronchial epithelium is a premalignant change associated with chronic smoking.
• EGFr expression is being investigated as a potential biomarker in lung cancer development and chemoprevention.

Purpose of the Study:

• To evaluate EGFr expression as a biomarker for bronchial metaplasia in smokers.
• To assess the impact of smoking cessation and 13-cis retinoic acid (13cRA) on EGFr expression and bronchial metaplasia.
• To determine if baseline EGFr levels predict response to chemoprevention.

Main Methods:

• Analysis of bronchial biopsies from 69 smokers in a randomized placebo-controlled chemoprevention trial.
• Quantification of EGFr expression in normal and metaplastic bronchial tissues.
• Correlation of EGFr levels with smoking cessation, metaplasia status, and 13cRA treatment.

Main Results:

• EGFr expression was significantly higher in metaplastic bronchial biopsies compared to normal ones (P=0.02).
• Smoking cessation during the trial correlated with reduced metaplasia (P<0.001) and lower EGFr expression (P=0.02).
• 13cRA treatment did not significantly alter EGFr expression (P=0.23), and baseline EGFr did not predict metaplasia reversal.

Conclusions:

• Elevated EGFr expression serves as a biomarker for bronchial metaplasia in smokers.
• The study did not support EGFr as a predictive biomarker for retinoid treatment response in lung cancer chemoprevention.
• Smoking cessation is associated with reversal of metaplasia and reduced EGFr expression, mediated by metaplasia reversal.