By increasing the immunogenicity of tumor cells, inosine, a purine metabolite produced by Akkermansia muciniphila and Bifidobacterium pseudolongum, enhances tumor cell susceptibility to recognition and elimination by cytotoxic T lymphocytes.34 In addition, short-chain fatty acids (SCFAs) and butyrate produced by intestinal anaerobic bacteria can enhance the anti-tumor cytotoxicity of CD8+ T cells in vitro and in vivo. The gene discussed is CD8A; the disease is neoplasm.