Figure 3.

The mechanisms underlying the immunostimulatory involvement of gut microbiota in cancer immunotherapy. Anticancer therapies such as chemotherapy, radiotherapy and immunotherapy can increase permeability of gut epithelial, translocation of bacteria and dysbiosis. During cancer therapy, antibiotics are sometimes used to treat opportunistic infection, which can also lead to disruption of gut microbiota. The mechanism of immunostimulation by gut microbiota includes ligation of PRR and PAMP, release of microbial metabolites such as SCFAs, LPS and inosine, and cross‐reactivity of bacteria epitope‐specific T cells and tumor antigen‐specific T cells. LPS, Lipopolysaccharides; MDSC, myeloid‐derived suppressor cells; PAMP, pathogen‐associated molecular patterns; PRR, pattern recognition receptor; SCFAs, short‐chain fatty acids.