THE ASSESSMENT OF PROLIFERATING CELL NUCLEAR ANTIGEN (PCNA) IMMUNOSTAINING IN HUMAN BENIGN AND MALIGNANT EPITHELIAL LESIONS OF THE PAROTID-GLAND

Immunoreactivity of proliferating cell nuclear antigen (PCNA) was asse ssed in formalin-fixed, paraffin-embedded sections from human normal p arotid gland (N; n = 12), chronic sialadenitis (CS; n = 8), Warthin's tumour (W; n = 10), benign pleomorphic adenoma (BPA; n = 11), mucoepid ermoid carcinoma (MEC; n = 14), carcinoma in pleomorphic adenoma (CPA; n = 10) and adenoid cystic carcinoma (ACC; n = 12) of the parotid gla nd, using the monoclonal antibody PC 10. The morphometric parameters m easured comprised PCNA labelling indices (PI = the numerical percentag e of PCNA positive nuclei) and volume densities of PCNA positive nucle i (V-V,V- PEP = the relative volume of positive nuclei per unit volume of reference epithelium). All parameters were expressed in relation t o total positive, as well as to strongly- and weakly-positive nuclei. In general, the values of PCNA parameters increased progressively in b enign lesions in comparison with the N group, and in malignant neoplas ms in comparison with non-neoplastic groups and benign lesions. The st rongly-positive parameters showed more statistically significant diffe rences than weakly-positive ones, suggesting that weakly-stained nucle i may include some non-cycling cells and, therefore, that weakly-posit ive parameters may not be reliable proliferation markers. Values for a ll parameters in CPA were significantly higher than those in BPA, sugg esting that these parameters may be used as diagnostic discriminators. Spearman rank correlation analysis showed a highly positive correlati on between the morphometric parameters and the severity of the lesions . Furthermore, the mean values of PISP were significantly higher in pa tients who died of the malignant tumours than in those patients who su rvived. Our results indicate that PCNA indices might be useful markers for discriminating between benign (BPA) and malignant tumours of the parotid gland and that the parameter PISP may have prognostic applicat ions. (C) 1997 Elsevier Science Ltd. All rights reserved.