ISG15 and hepatocellular carcinoma: For HCC resection samples, all the patients showed HBs-Ag (+), HBe-Ag (−) and HBe-Ab (+) and were categorized as either HBV DNA positive or negative per HBV DNA levels in the serum, and ISG15 and N4BP1 mRNA expressions were assayed in non-cancerous liver tissue from these patients (Fig. 9a, b).