[Expression of proliferating cell nuclear antigen (PCNA) in squamous cell carcinoma of the oral cavity].

Proliferating cell nuclear antigen (PCNA) was identified by immunohistochemistry in 52 cases. PCNA-positive cells had been detected in the basal cells of normal epithelium known to contain proliferating cells. PCNA scores of normal epithelium was 1 as "low", and carcinomas were 3 or 4 as "high". The PCNA scores of high-grade carcinoma was significantly higher than the low-grade carcinoma. The study shows that expression of PCNA correlated with carcinoma grade.