Proliferative activity as detected by immunostaining with Ki-67 and proliferating cell nuclear antigen in benign and malignant epithelial lesions of the human parotid gland

OBJECTIVE: A retrospective immunohistochemical study of parotid gland lesio ns was designed to evaluate the diagnostic and prognostic value of the prol iferating cell nuclear antigen (PCNA) and Ki-67 with monoclonal antibodies PC 10 and MIB-1, respectively. STUDY DESIGN: Tissue samples comprised normal parotid gland (N, n=10), chro nic sialadenitis (CS, n=8), Warthin's tumor (W, n=10), benign pleomorphic a denoma (BPA, n=8), mucoepidermoid carcinoma (MEC, n=13), carcinoma in pleom orphic adenoma (CPA, n=8) and adenoid cystic carcinoma (ACC, n=12). The mor phometric parameters for PCNA and MIB-1 comprised the PI and MI labelling i ndices (the numerical percentage of positive nuclei), N-AP and N-AM (the nu merical density of positive nuclei), and NPI and NMI (volume corrected inde x). RESULTS: The values of MIB-1 parameters increased progressively in benign l esions in comparison with the N group and in malignant neoplasms in compari son with nonneoplastic groups and benign lesions. Values for all parameters in BPA were significantly lower than those in malignant groups. Spearman r ank correlation analysis showed a highly positive correlation between the m orphometric parameters and severity of the lesions. The mean values of MI a nd NMI were significantly higher in patients who died of the malignant tumo rs than in those mho survived. The same quantitative parameters for PCNA di d not differ significantly from those obtained for MIB-1 and showed similar trends. CONCLUSION: PCNA and MIB-1 indices are reliable markers for discriminating between benign and malignant tumors of the parotid gland, and the parameter s PI, MI, NPI and NMI may have prognostic applications.