PLEOMORPHIC ADENOMA AND ADENOID-CYSTIC CARCINOMA OF SALIVARY-GLANDS -IMMUNOHISTOCHEMICAL ASSESSMENT OF PROLIFERATIVE ACTIVITY IN COMPARISON WITH FLOW-CYTOMETRIC

In this study, 32 pleomorphic adenomas (PAs) and seven adenoid cystic carcinomas (ACCs) were analysed for the evaluation of proliferating ce ll nuclear antigen (PCNA) indices and flow cytometric variables. Our a im was to assess any possible relationship between these parameters an d the clinico-pathological variables and to clarify their histogenesis and reasons for their biological differences. The tumours were divide d into three groups, mainly epithelial (E), myxoid (M) and chondroid ( C); PCNA labelling index (LI) and weighted mean index (WI) and the WI/ LI ratio were analysed in the predominant components; a single PCNA in dex, weighted by the percentage of each component, was also calculated . Only WI/LI was found to be significantly different in the three comp onents, while PCNA single index did not show either significant differ ences by sex, age, site and size, or any correlation with the S phase fraction. A significant difference was found between PAs and ACCs by s ite (P<0.01) and DNA ploidy (P<0.05); furthermore, all PCNA indices (s ingle index) were significantly lower in PAs than in ACCs.