CLARA CELL 10-KDA PROTEIN MESSENGER-RNA IN NORMAL AND ATYPICAL REGIONS OF HUMAN RESPIRATORY EPITHELIUM

We used RNA-RNA in situ hybridization to study expression of the human CC 10 gene in morphologically normal and atypical areas of 32 non-neo plastic lung specimens resected from 26 non-small cell lung cancer pat ients. We scored strong, moderate or weak levels of CC 10 mRNA express ion in 3 distinct lung compartments. In morphologically normal lungs, strong and moderate levels of CC10 mRNA were observed in bronchioli an d bronchi, respectively, but the expression was rarely observed in the alveolar region. Distinct alterations in CC10 mRNA expression were no ted in specific histologic abnormalities within bronchi and the alveol ar region. CC10 hybridization signal decreased markedly in bronchi con taining diffuse goblet cell hyperplasia or squamous metaplasia, while CC10 mRNA expression remained unchanged in bronchi with basal cell hyp erplasia or focal goblet cell hyperplasia. Bronchiolar CC10 mRNA level s remained unchanged in sections containing abnormalities elsewhere. I nterestingly, in alveoli with bronchiolization of the alveoli, high le vels of CC10 mRNA were observed. These regions also contained strongly stained keratin 14-positive cells, which may indicate a concurrent me taplastic process. In lungs with morphologic atypias, no correlation w as found between abnormalities detected in bronchi and alveoli from th e same lung. A comparison of mRNA expression and clinicopathologic fea tures demonstrated that the amount of histologic abnormalities increas ed with smoking history (pack years); however, no correlation between CC10 mRNA expression and sex, age or smoking history was found. (C) 19 94 Wiley-Liss, Inc.