Table 1.

Summary of the mechanisms of different intestinal microflora in the initiation, development, and metastasis of CRC

Enteric microorganisms	Mechanism of action	Authors	Year
F. nucleatum	through FadA, it selectively binds to E-cadherin on the surface of CRC and activates the intracellular β-catenin signaling pathway	Hashemi Goradel et al.30	2019
E. faecalis	metalloproteinase is produced, directly destroying the intestinal epithelial barrier and inducing inflammation	de Almeida et al.33	2018
E. coli	gene toxin E. coli was produced by the NRPS-PKS hybrid gene cluster	Vizcaino et al.34	2015
ETBF	produces BFT, which has proteolytic activity, can damage intestinal mucosa, induces cancer-promoting signal cascade, and triggers medullary cell-dependent colon tumors	Chung et al.35,36	2018
P. anaerobius	its surface protein PCWBR2 directly combines with IEC receptor integrin a2/b1 to activate the carcinogenic PI3K-Akt signal pathway, thus promoting the proliferation of tumor cells	Belkaid et al.37	2014
SE	secretion of AvrA activates the STAT3 signaling pathway in colon cancer cells	Duijster et al.38	2021
CJ	CDT production leads to DNA double-strand break	Lara-Tejero et al.39	2000