Expression of interleukin-18, interferon-γ and interleukin-10 in hepatocellular carcinoma

This is the first report on the detection of IL-18, IFN-gamma and IL-10 proteins in hepatocelllular carcinoma. In the apparently normal surrounding tissue, 13 out of 17 paired specimens showed positive immunoreactivity to IL-18 (76.5%) compared with six out of 17 in the turnout portion (35.3% of specimens). Thus, a significantly higher number of IL-18 positive specimens was found in the hepatocytes of apparently normal surrounding tissue compared with the tumour (P = 0.018). In contrast, the number of specimens with positive immunoreactivity to the antibody against the Th1 cytokine, IFN-gamma expression in the hepatocytes was lower. Only one specimen from the apparently normal surrounding tissue (one out of 17; 5.9%) and three other specimens from the tumour portion (three out of 17; 17.6%) had positive immunoreactivity. Similarly, the expression of the Th2 cytokine, IL-10 in normal (four out of 17; 23.5%) and tumour portions (five out of 17; 29.4%) was also low. Thus, there did not appear to be predominant Th2 immune response as denoted by IL-10 expression. Using the Spearman correlation rank test, a significant correlation between IL-18 expression in the apparently normal surrounding tissue and high alpha-foetoprotein (AFP) levels of > 350 IU/l. No correlation between IL-18 expression in the tumour portion and clinicopathological factors was found. There was also no correlation found between IL18 and the other cytokines, namely, IFN-gamma and IL-10 expression These new findings provide additional information on the type of cytokines expressed in the tumour microenvironment and give a further insight into the role of cytokines in the pathogenesis of cancer which is critical for the development of effective immunotherapeutic approaches for cancer therapy in the future. (C) 2002 Elsevier Science B.V. All rights reserved.