Fig. 1.

The schematic illustration represents the connection between colorectal cancer's sequential progression and the gut microbiome. Interactions between the host and the microbe lead to activate pro-carcinogenic signaling pathways, which in turn cause molecular changes that speed up CRC. In the colorectal epithelium, certain gut microbes, including Peptostreptococcus anaerobius, Fusobacterium nucleatum, sulfate-reducing bacteria, Enterococcus faecalis, Campylobacter jejune, Streptococcus bovis, Bacteroids fragilis, Salmonella spp., and Escherichia coli, cause persistent inflammation. Through changes in several signaling pathways and the production of proinflammatory cytokines, these microbial elements damage DNA and break down the barrier in the gut. Nevertheless, several treatments, such as antibiotics and FMT, inhibit the growth of microbes and colonization.