Immunohistochemical expression of p53 protein and proliferating cell nuclear antigen in hepatocellular carcinoma.

There is an increased prevalence of p53 mutations in hepatocellular carcinomas (HCCs). A total of 62 HCC samples with adjacent liver tissue were analyzed immunohistochemically for the presence of p53 by two different commercial sources of Pab 1801. Polyclonal antibodies anti-HbsAg and anti-HbcAg were employed for the detection of HBV in the adjacent tissue and PC-10 for the detection of proliferating cell nuclear antigen (PCNA). Positive staining for p53 was identified in 42% and 55% of the HCC cases using each monoclonal antibody. p53 was found in 42% of the low grade and 43% of the high grade HCC. In 32% of the HCC cases, p53 was found in the adjacent liver tissue. In 52.6% of the cases with evidence of HBV infection, p53 positive expression was observed. PCNA was detected in 56% of the HCC cases (69% low grade, 57% high grade HCC). Eighty-one percent of the p53 positive tumours expressed PCNA, mostly with a high index. p53 and PCNA were not related to histologic grade. A trend for positive correlation was observed between p53 expression and HBV infection. The detection of p53 in non neoplastic tissue and the absence of a significant correlation between p53 expression and degree of differentiation support the hypothesis that the p53 gene mutation is involved in early stages of hepatocellular carcinogenesis.