Objective To preliminarily investigate the expression of cysteine proteinase inhibitors C (cystatin C) in primary hepatic carcinoma. Methods Hepatic tissue samples and peripheral blood samples were collected from 41 cases of primary hepatic carcinoma, 24 cases of cirrhosis and 40 cases of normal control. To primary hepatic carcinoma, three kinds of hepatic tissue samples were harvested, including carcinoma tissue, adjacent non-tumor tissue，and distant normal tissue. The expression levels of cystatin C in hepatic samples and blood samples were measured by immunohistochemistry method and latex enhanced immune turbidimetric method respectively, and the differences of cystatin C expressions were compared in primary hepatic cancer, cirrhosis, and normal control. Furthermore, the relationships of cystatin C expression with tumor size, intrahepatic metastasis, serum AFP level were studied with correlation analysis. Results The expression of cystatin C was positive, in primary hepatic carcinoma. Part of adjacent non-tumor tissue，and distant normal tissue and cirrhosis tissues had some degree of cyctatin C expression. Wilcoxon test showed that the differences of cyctatin C expression in different hepatic tissues were statistics significance (P<0.01). The proportion of positive cell， staining intensity, and the product of these two was: carcinoma tissues＞ adjacent non-tumor tissues＞ cirrhosis tissues＞ distant normal tissue. Compared with normal control, primary hepatic carcinoma and cirrhosis both had higher serum cystatin C level (P<0.001), but there was no difference between hepatic carcinoma and cirrhosis （P=0.769）. The correlation analysis showed that the level of serum cystatin C was not related to serum AFP, tumor size, or intrahepatic metastasis. Conclusion The expression of cystatin C in primary hepatic carcinoma is higher than that of adjacent non-tumor tissue， distant normal tissue, and cirrohsis tissue. The serum cystatin C level of primary hepatic carcinoma is higher than that of normal control.
