To investigate the associations between serum IL-6 levels and OCT4 and DNMT mRNA in human HCC tissues, serum IL-6 levels from 144 HCC patients were compared with OCT4 and DNMT mRNA levels from paired frozen tumor tissue (T) and adjacent peritumor tissue (PT) samples (Table 1 and Additional file 1: Figure S1) using ELISA and real-time qRT-PCR. The gene discussed is IL6; the disease is hepatocellular carcinoma.