The expression of proliferating cell nuclear antigen in hepatocellular carcinoma

Proliferating cell nuclear antigen (PCNA), also known as cyclin, is a cell cycle-related nuclear protein which accumulates in late G1 and S phases of proliferating cells. Previous researches have demonstrated it is a potentially useful tool for the study of tumor proliferative activity and have correlated it with tumor grade.

In this study, PCNA was identified by utilizing streptavidin-biotin immunoperoxidase technique on formalin-fixed, paraffin-embedded tissue sections of 32 hepatocellular carcinomas that were obtained from resected surgical specimens.

The PCNA staining was entirely confined to the nucleus and showed gradation of intensity. The staining rates in tumor cells ranged from 0% to 99%. The mean (+/- S.D.) PCNA staining rates of 5 in grade I, 20 in grade II, and 7 in grade III hepatocellular carcinomas were 0.38 +/- 0.15%, 19.39 +/- 18.86% and 49.57 +/- 29.98%, respectively, and showed statistically significant difference (P < 0.01) between each other. There was no statistical difference in the mean PCNA staining rate of various histological types among hepatocellular carcinoma (P > 0.05). In 12 of 32 hepatocellular carcinomas, each PCNA staining of non-neoplastic hepatic tissue adjacent to the tumor was also evaluated and their mean PCNA rate (0.59 +/- 0.58%) revealed no significant difference (P > 0.05) from grade I hepatocellular carcinoma.

The hepatocellular carcinoma's mean proliferating cell nuclear antigen staining rates were correlated with its first three histological grades but revealed no statistical difference among its histological types. The mean proliferating cell nuclear antigen staining did not differentiate non-neoplastic hepatic diseases that were adjacent to hepatocellular carcinoma, including chronic active hepatitis, cirrhosis of liver, reactive hepatitis, schistosomiasis and nuclear dysplasia, from grade I hepatocellular carcinoma.