Abstract：Current studies mostly emphasize the beneficial role of short-chain fatty acids SCFAs in the prevention and treatment
of colorectal cancer such as reducing the incidence of colorectal cancer by inhibiting chronic intestinal inflammatory response
providing energy to intestinal epithelial cells and maintaining intestinal mucosal epithelial homeostasis. In addition SCFAs can inhibit
the proliferation of colon cancer cells by antagonizing histone deacetylases HDACs . By activating caspase-3 signaling pathway tumor
cell apoptosis can be promoted and anti-tumor immunity can be activated which has therapeutic effects on colorectal cancer. However
recent epidemiological studies have shown that elevated levels of some SCFAs in the blood of colorectal cancer patients are risk factors
for the development of colorectal cancer. Further studies showed that intestinal supplementation of butyric-producing bacteria promoted
the development of colorectal cancer in mice and the cancer-promoting effect was inhibited by knockdown of the butyric-producing
gene of bacteria. In other clinical studies high levels of butyric acid have been found in the blood of tumor patients to inhibit ipilimumab induced T cells and interleukin-2 IL-2 infiltration and reduce the efficacy of cytotoxic T lymphocyte associated antigen 4 CTLA4 antibody in tumor treatment. These studies suggest that SCFAs play a beneficial role in the prevention and treatment of colorectal
cancer under certain conditions beyond which there will be negative effects. Therefore when applying SCFAs in clinical work for the
prevention and treatment of colorectal cancer it is necessary to guard against the negative effects of inappropriate application of SCFAs.
