Figure 4.

The mechanism of intestinal flora regulating the occurrence and development of tumors. Intestinal bacteria can directly cause intracellular DNA damage by producing genotoxins, or activate the NF-κB and STAT3 pathway by promoting cytokines secretion to promote tumorigenesis. Intestinal bacteria can also activate a range of oncogenic pathways. Increased release and translocation of β-catenin into the nucleus through degradation of the E-cadherin/β-catenin complex leads to aberrant activation of WNT signaling associated with various cancers. Besides, they can lead to the invasion and metastasis of cancer by activating TLR4/Keap1/NRF2 signaling. Furthermore, LPS produced by bacteria has been shown to promote the Kla of histones, which in turn promotes tumor progression. LPS, Lipopolysaccharide; TLR4, Toll-like receptor 4; Nrf2, Nuclear factor E2-related factor 2; NF-κB, Noncanonical nuclear factor-kappaB; STAT3, ignal transducer and activator of transcription 3.