Unmasking the microbiome: the hidden role of gut bacteria in the pathogenesis of colorectal cancer and its prevention strategies

Colorectal cancer (CRC) is a significant global health problem, ranking as the third most common cancer and the second leading cause of cancer deaths in the world. The highest incidence of CRC is found in developed regions, thus underlining its characterization as a Western disease. Major risk factors for CRC include an unhealthy diet, lack of physical exercise, and cigarette smoking. The gut microbiota refers to the complex community of microorganisms inhabiting the digestive tract and plays a crucial role in the maintenance of host health and modulation of immune responses. Gut dysbiosis can be caused by poor diet and alcohol consumption, increasing CRC risk. Specific bacteria, such as <i>Fusobacterium nucleatum</i> and <i>Escherichia coli</i>, may have a close relationship with CRC development, while the beneficial bacteria are frequently depleted in CRC patients. This paper will discuss the mechanisms of colorectal carcinogenesis, focusing on the effects of bacterial genotoxins, immune evasion, inflammation, and diet. Additionally, it reviews preventative strategies including short-chain fatty acids (SCFAs), prebiotics, probiotics, synbiotic supplements, and the method of fecal microbiota transplantation (FMT), showing their potential to improve overall gut health and reduce the risk for CRC. Understanding these mechanisms and implementing specific preventative strategies could significantly enhance clinical interventions and reduce the global burden of CRC.