EXPRESSION OF MARKERS OF DIFFERENTIATION IN NORMAL BRONCHIAL EPITHELIUM AND BRONCHIAL DYSPLASIA

Bronchial epithelial dysplasia is a non-invasive cellular change often associated with physical or chemical injury and considered a pre-neop lastic lesion in the formation of lung cancer. A series of 39 bronchia l dysplasias associated with both neoplastic and non-neoplastic lesion s mere assessed for expression of markers of differentiation by immuno cytochemistry and compared with samples of normal bronchial epithelium . The normal bronchial epithelium studied expressed cytokeratins (CKs) 4, 6, 7, 8, 18, and 19 in all cases; CK 13 in 13 cases; and peanut ag glutinin (PNA) in seven cases. Involucrin, CK 10, and CK 14 were not o bserved in the normal bronchial samples. In the dysplastic bronchial b iopsies, epithelial staining was observed with epithelial CKs 7, 8, 18 , and 19 in all cases; CK 13 was seen in 26 cases; CK 14 in 13 cases; CK 6 in 11 cases; and CK 10 in five cases. In 13 cases of dysplasia, o nly simple epithelial antigens were identified. Involucrin expression was observed in 17 dysplastic biopsies and PNA in 12. By Fisher's exac t test, a significant association between non-severe histological grad e of dysplasia and CK 6 expression (P=0.018) was found. Comparison of the results using the same analysis showed significant correlations be tween the loss of CK 6 expression (P<0.001) and the expression of CK 1 4 (P=0.008) and involucrin (P=0.0018) with bronchial dysplasia. These data show that the pattern of differentiation antigen expression in br onchial dysplasia is significantly different from that of the normal b ronchial epithelium, but the phenotypic heterogeneity of these lesions is similar to that of bronchial carcinomas.