Evaluation of serum interleukin-6 levels in hepatocellular carcinoma patients: a systematic review and meta-analysis

AIM OF THE STUDY: This meta-analysis evaluated serum interleukin-6 (IL-6) levels in hepatocellular carcinoma (HCC) patients compared with healthy controls and hepatitis and cirrhotic patients. MATERIAL AND METHODS: The three databases PubMed, Scopus, and Web of Science were searched for assessment of IL-6 levels in HCC patients (without cirrhosis and hepatitis) compared with healthy controls (without HCC, cirrhosis and hepatitis) and the studies were selected based on inclusion and exclusion criteria. A random-effect meta-analysis was performed with RevMan 5.3 software, using mean difference (MD) and 95% confidence intervals (CIs). RESULTS: Out of 503 studies searched in databases, 18 studies were included in the meta-analysis. The pooled analysis with continuous data demonstrated that the IL-6 level in HCC patients was significantly higher than that in healthy controls (MD = 12.44; 95% CI: 9.02-15.85; p < 0.00001). Also, the pooled analysis demonstrated that the IL-6 levels in cirrhotic patients (MD = –6.98; 95% CI: –12.91-1.05; p < 0.02) and patients with hepatitis (MD = –8.43; 95% CI: –11.91-4.95; p < 0.00001) were significantly lower than the level in HCC patients, and the subgroup analyses had high heterogeneity. CONCLUSIONS: The elevated IL-6 levels in HCC patients compared with hepatitis and cirrhosis patients and healthy controls may show a significant association of this cytokine with increased risk of HCC and its potential as a diagnostic marker for HCC in future diagnostic and therapeutic strategies.