MLH1 and colorectal carcinoma: CRC development is closely linked with hypermethylation, which can slience tumor suppressor gene.122 Recently, Xia and colleagues found that the Hungatella hathewayi and F. nucleatum enriched in CRC were significantly associated with CDX2 and MLH1 (both are antioncogenes) promoter hypermethylation, respectively, through which the bacteria may drive intestinal tumorigenesis.123 Mechanistically, in vitro and in vivo experiments have demonstrated that both bacteria could upregulate DNA methyltransferase, which is required for hypermethylation.123