Immunohistochemical study of p53 tumor suppressor gene product and proliferating cell nuclear antigen in oral squamous cell carcinoma.

Forty-one oral squamous cell carcinomas were immunohistochemically examined for p53 protein and PCNA. Twenty-six cases (63.4%) showed p53 overexpression, but the frequency of p53 protein was not correlated with the degree of histological differentiation.PCNA LI was inversely correlated with the grade of histological differentiation. There was no significant difference in PCNA LI between the p53-positive group and the p53-negative group. In p53-positive cases, p53 protein and PCNA showed similar staining patterns. These results indicated that the degree of histological differentiation is associated with proliferative potential, but not with the presence of p53 protein.