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.