IL18 and hepatocellular carcinoma: When comparing the difference in serum IL-18 levels between the two groups among individuals with the same genotype, a similar situation was found in which IL-18 levels in HBV-related HCC patients with the -607C/A AA, AC, and CC genotypes and −137G/C GG and GC genotypes were all significantly lower than in healthy control subjects (all P < 0.05).