| [ Summary ] |
The link between cancer and microbiota is well established. Bacteria in the intestine can modulate tumor initiation and development through various mechanisms, including direct and indirect. The direct mechanisms are those in which microbial products and toxins directly promote tumor initiation and progression, whereas the indirect mechanisms are those in which bacteria influence the immune system, thus affecting the tumor development. Escherichia coli (E. coli), Fusobacterium nucleatum, and Bacteroides fragilis have been previously linked to colorectal cancer. E. coli pks+ produces colibactin toxin, which can generate double‒strand breaks (DSBs) in the DNA of host cells. It has become evident that the gut microbiota modulates the response to cancer therapy. Further, there are many drugs that are metabolized by microbiota. Direct interaction with bacteria can affect the efficacy of chemotherapy. In cancer patients, anti‒tumor immunity remains suppressed. Recent studies have reported the role of the gut microbiota in regulating the efficacy of anti‒CTLA4 and anti‒PDL1 cancer therapy. |