Microbiota, NASH, HCC and the potential role of probiotics.

Hepatocellular carcinoma (HCC) accounts for the majority of primary liver cancers. Clearly identifiable risk factors are lacking in up to 30% of HCC patients and most of these cases are attributed to non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). Beyond the known risk factors for NAFLD, the intestinal microbiota, in particular dysbiosis (defined as any change in the composition of the microbiota commonly found in healthy conditions) is emerging as a new factor promoting the development of chronic liver diseases and HCC. Intestinal microbes produce a large array of bioactive molecules from mainly dietary compounds, establishing an intense microbiota-host transgenomic metabolism with a major impact on physiological and pathological conditions. A better knowledge of these 'new' pathways could help unravel the pathogenesis of HCC in NAFLD to devise new prevention strategies. Currently unsettled issues include the relative role of a 'negative microbiota' (in addition to the other known risk factors for NASH) and the putative prevention of NAFLD through modulation of the gut microbiota.