• Bacteria, the cause or cure of colorectal cancer
  • Foroogh Hatami,1,*
    1. Department of Biotechnology, Ialamic Azad University, North Tehran Branch


  • Introduction: Colon cancer is one of the most commonly diagnosed malignancies with an upward trend of morbidity. The incidence and mortality of colorectal cancer (CRC) have been increasing over the last 25 years. Some factors can increase the risk of CRC, for example, obesity, sedentary lifestyle, smoking, alcohol intake, diet, and diabetes. It has recently been recognized that the gut microbiome has a key role in colorectal carcinoma development. The human gastrointestinal tract contains more than 100 trillion bacteria, fungi, and viruses. Gut microbiota is involved in the transformation of food components into oncometabolite.
  • Methods: several studies have demonstrated an association between changes in microbiota composition and an increased risk of CRC. various bacterial strains are associated with CRC, such as Fusobacterium nucleatum, and Escherichia coli. Some studies showed that Fusobacterium nucleatum expression increased in tumor tissue, and this bacteria was also more abundant in feces from CRC patients. E. coli has the potential to cause intestinal inflammation via toxins such as colibactin, which has also oncogenic potential. In addition to bacterial virulence factors, some microbial metabolites affect the development of CRC, like glucuronic acid.
  • Results: Pathogenic bacteria may participate in the pathogenesis of CRC when the gut microbial homeostasis is disturbed. In contrast, some other types of bacteria such as Lactic acid bacteria as probiotics can reduce inflammation. Probiotics make a variety of biological benefits, containing the anti-activity of pathogenic bacteria, regulating the immune system, and preventing CRC. Increasing studies in this field shows that gut microbiota plays a vital role in the development of CRC. Despite this, some other bacteria such as lactic acid bacteria with probiotic properties will probably be a powerful tool for combating CRC.
  • Conclusion: The goal of this review is to show the relationship between gut microbiota and the development of CRC as well as the potential mechanisms of microbiota involved in the treatment of CRC.
  • Keywords: colorectal cancer, microbiome, probiotics, gastrointestinal tract, bacteria