IL-6, through p-STAT3 rather than p-STAT1, activates hepatocarcinogenesis and affects survival of hepatocellular carcinoma patients: a cohort study

BACKGROUND: Biologic activities of functional mediators activate downstream transducers regulating inflammation and carcinogenesis. Correlation among mediators (IL-6, IL-27, TNF-α, and VEGF) with STAT proteins at diverse clinical-pathologic stages of hepatocellular carcinoma (HCC) remains limited. METHODS: Serum mediators assayed from 147 untreated HCC cases (HCC-total group) included 70 HBV-infected (HCC-HBV group), 64 HCV-infected (HCC-HCV group), and 13 without HBV-/HCV-infection (HCC-NBNC group). Another 156 non-HCC individuals comprised 54 healthy individuals (HG) and 102 chronic hepatitis patients (CH-total group) as control group. To correlate with serum mediators, 86-paired liver tissues (CH: 52 and HCC: 34 cases) served for p-STATs proteins immunostain. RESULTS: Although four mediators (IL-6, IL-27, TNF-α, and VEGF) significantly over-expressed, IL-6 presented the strongest correlation in HCC-total versus CH-total or HG groups (HCC-total versus CH-total: P < 0.001; HCC-total versus HG: P < 0.001). Over-expressed IL-6 concentration linked with poor liver function (Albumin: r = −0.383, P < 0.001; Bilirubin: r = 0.280, P = 0.001; INR: r = 0.299, P < 0.001; AST: 0.212, P = 0.016), tumor progression (TNM system: r = 0.370; P < 0.001), clinical condition severity (BCLC system: r = 0.471; P < 0.001; terminal- versus early-stage HCC, P = 0.001; advanced- versus early-stage HCC, P = 0.007; terminal- versus intermediate- stage HCC P = 0.003; advanced- versus intermediate-stage HCC P = 0.019), and 6-month mortality (P = 0.024). Likewise, serum IL-6 (r = 0.501, P = 0.003) as compared to IL-27 (r = 0.052, P = 0.770), TNF-α (r = 0.019, P = 0.917), and VEGF (r = 0.096, P = 0.595) expression reflected positive correlation with activation of tissues p-STAT3 rather than p-STAT1. CONCLUSIONS: Serum IL-6, through p-STAT3 rather than p-STAT1 signal pathway, affected hepatic function, tumor progression, and determine HCC patient survival.