Figure 2.

A hypothetical schematic representation and overview of the inhibition against HCC. BAs, Th17/Treg balance, and/or certain gut microbiota could contribute to the potentiation of the immune checkpoint immunotherapy with immune checkpoint inhibitors. Some kinds of probiotics, prebiotics, and FMT could contribute to the alteration of gut microbial community for playing valuable roles to the immune checkpoint therapy. Examples of certain beneficial microbial species with several effects on anti-cancer immune responses have been shown at the left side. Arrowhead indicates stimulation whereas double-arrowheads suggests bidirectional stimulation. Hammerhead shows inhibition. Note that several important activities such as cytokine-induction and/or anti-inflammatory reaction have been omitted for clarity. mAB: monoclonal antibody