EXPRESSION OF PROLIFERATING CELL NUCLEAR ANTIGEN (PCNA) IN DYSPLASIA OF THE BRONCHIAL EPITHELIUM

Proliferating cell nuclear antigen (PCNA) is expressed in cells in the cell cycle and has been studied as a marker of proliferation in lung and other tumours. We have noted immunocytochemical differences in PCN A expression between normal and neoplastic bronchial cells. As bronchi al dysplasia is considered preneoplastic, we have examined PCNA expres sion in this condition. PCNA staining in 47 cases of bronchial dysplas ia and 32 samples of normal bronchial epithelium was compared. Of the dysplasias, three were mild, 11 moderate, and 33 severe. A significant increase in PCNA counts over normal epithelium was seen only in moder ate and severe dysplasias. In dysplasia, mitotic indices showed a sign ificant positive correlation with the percentage of PCNA-positive cell s. We conclude that in moderate and severe dysplasias there is an incr ease in the number of cells expressing PCNA and undergoing division, i ndicating abnormal growth control.