Hepatocellular carcinoma (HCC) ranks the third place among all causes inducing cancer-associated mortality, worldwide. HCC nearly exclusively occurs in cases suffering from chronic liver disease (CLD), which results from the vicious cycle of liver damage, inflammation, and regeneration possibly lasting for dozens of years. Recently, more and more investigation on microbiome-gut-liver axis enhances our understanding toward how gut microbiota promotes liver disease and even HCC development. In this review, we summarize the mechanisms underlying the effect of gut microbiota on promoting HCC occurrence, with the focus on key pathways such as bacterial dysbiosis, leaky gut, bacterial metabolites, and microorganism-related molecular patterns, which promote liver inflammation, genotoxicity, and fibrosis that finally lead to cancer occurrence. Furthermore, we discuss gut microbiota’s important potential to be the early diagnostic biomarker for HCC. Gut microbiota may be the candidate targets to simultaneously prevent CLD and HCC occurrence among advanced liver disease cases. We outlook the gut microbiota-targeting treatments in detail to prevent CLD and HCC progression.

Asthma and atopy, classically associated with hyper-activation of the T helper 2 (Th2) arm of adaptive immunity, are among the most common chronic illnesses worldwide. Emerging evidence relates atopy and asthma to the composition and function of gut microbiota composition. Moreover, certain gut microbial strains have been shown to inhibit or attenuate immune responses associated with chronic inflammation in experimental models. Although still a relatively nascent field of research, evidence to date suggests that the gut microbiome may represent fertile targets for prevention or management of allergic asthma and other diseases in which adaptive immune dysfunction is a prominent feature. The oral probiotics/prebiotic represents a possible therapeutic for improving asthma and allergic disease. Especially, recent technological developments that permit identification of microbes and their products using culture-independent molecular detection techniques. In this review, we literaturely summarise the aggravation or improvement of metabolic diseases by role of gut microbiota, probiotics/prebiotic treatment.