INCREASED EPIDERMAL GROWTH-FACTOR RECEPTOR EXPRESSION IN METAPLASTIC BRONCHIAL EPITHELIUM

Epidermal growth factor receptor (EGFr) is expressed in human bronchia l epithelial cells, and non-small cell lung cancers express increased EGFr, Squamous metaplasia of the bronchial epithelium occurs in chroni c smokers and is considered an early premalignant change, In this stud y, EGFr expression was examined in biopsies of histologically normal a nd metaplastic bronchial tissues obtained from 69 smokers who were enr olled in a randomized placebo-controlled chemoprevention trial. This t rial tested the effects of 6 months of treatment with 13-cis retinoic acid (13cRA) on bronchial metaplasia, EGFr expression was examined as a marker of bronchial metaplasia and response to 13cRA treatment. In b ronchial biopsies obtained from patients in this study, EGFr expressio n was higher in metaplastic biopsies than in normal biopsies (P = 0.02 ). Smoking cessation during treatment correlated with reduced metaplas ia (P < 0.001) and EGFr expression (P = 0.02), but multivariate analys is suggested that this effect of smoking cessation on EGFr expression was dependent upon reversal of bronchial metaplasia, 13cRA treatment d id not alter EGFr expression (P = 0.23), Baseline EGFr expression leve ls in metaplastic biopsies did not predict metaplasia reversal, This s tudy demonstrated that increased EGFr expression is a biomarker of bro nchial metaplasia, but it did not support the hypothesis that EGFr is a biomarker of retinoid response in lung cancer chemoprevention trials .