Assessment of proliferating cell nuclear antigen immunostaining in parotid tumors

We evaluated the prognostic value of immunostaining proliferating cell nuclear antigen (PCNA) by using a monoclonal antibody (PC10) in patients with parotid tumors. Twenty-seven cases were studied. Immunohistochemical studies were carried out on paraffin-embedded tissues from the patients, and the PCNA index was calculated as the percentage of positively staining tumor cells. The PCNA index ranged from 0.1 to 65.3%. We divided the 27 lesions into three groups histologically: group A with benign pleomorphic tumors (11 cases), group B with low-grade malignant tumors (5 cases), and group C with high-grade malignant tumors (11 cases). The mean PCNA index was 0.7% in group A, 2.0% in group B, and 23.1% in group C. The clinical data revealed a significantly higher local tumor recurrence and mortality rate in group C than in groups A and B. We conclude that PCNA may be used as an important indicator for determining clinical prognosis in parotid tumors.