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Our findings indicate that genomic instability derived during the IL6-mediated liver regenerative response within a milieu of chronic inflammation links partial hepatectomy to accelerated hepatocarcinogenesis; this suggests a new therapeutic approach through the usage of an anti-IL6 treatment to extend the tumor-free survival of patients undergoing surgical resection. (Hepatology 2017;65:1600-1611).

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The long-term prognosis after resection of hepatocellular carcinoma (HCC), which is one of the treatment options for early-stage HCC, remains unsatisfactory as a result of a high incidence of disease recurrence. Recent studies performed in murine models revealed a link between liver regeneration under chronic inflammation and hepatic tumorigenesis. Sorafenib is a potent drug for advanced HCC with multikinase inhibition activity. We propose that inhibition of signal transduction pathways which are activated during hepatectomy, using Sorafenib, will reduce accelerated tumorigenesis. To test this hypothesis, we studied the Mdr2-knockout (KO) mouse strain, a model of inflammation-associated cancer, which underwent partial hepatectomy (PHx) at three months of age, with or without Sorafenib.Here we show that Sorafenib treatment during PHx inhibited different signal transduction pathways at the multikinase levels, but did not result in increased morbidity or mortality. At the early stages after PHx, Sorafenib treatment had no effect on the course of proliferation, apoptosis and DNA repair in the regenerating liver, but resulted in decreased stellate cells activation and inflammatory response. Finally, we show that Sorafenib treatment during PHx at three months of age resulted in decreased fibrosis and tumor formation at 8.5 months.In conclusion our study indicates that short-term Sorafenib treatment during PHx is safe and effective in inhibiting inflammation-associated cancer, and is therefore a potential strategy for recurrence prevention in patients with early-stage HCC treated with PHx.

Hepatocellular carcinoma (HCC) typically develops on a background of chronic hepatitis for which the proinflammatory cytokine IL6 is conventionally considered a crucial driving factor. Paradoxically, IL6 also acts as a hepatoprotective factor in chronic liver injury. Here we used the multidrug-resistant gene 2 knockout (Mdr2−/−) mouse model to elucidate potential roles of IL6 in chronic hepatitis–associated liver cancer. Long-term analysis of three separate IL6/Stat3 signaling–deficient Mdr2−/− strains revealed aggravated liver injury with increased dysplastic nodule formation and significantly accelerated tumorigenesis in all strains. Tumorigenesis in the IL6/Stat3-perturbed models was strongly associated with enhanced macrophage accumulation and hepatosteatosis, phenotypes of nonalcoholic steatohepatitis (NASH), as well as with significant reductions in senescence and the senescence-associated secretory phenotype (SASP) accompanied by increased hepatocyte proliferation. These findings reveal a crucial suppressive role for IL6/Stat3 signaling in chronic hepatitis–associated hepatocarcinogenesis by impeding protumorigenic NASH-associated phenotypes and by reinforcing the antitumorigenic effects of the SASP. Significance: These findings describe a context-dependent role of IL6 signaling in hepatocarcinogenesis and predict that increased IL6-neutralizing sgp130 levels in some patients with NASH may herald early HCC development. See related commentary by Huynh and Ernst, p. 4671