ABSTRACT
Colorectal cancer is a common carcinoma of gastrointestinal tract, and its incidence is associated with genetic mutations, environment as well as inflammation. Recent studies have shown that many microorganisms may have played an important role in pathogenesis of colorectal cancer. The common bacteria involved in colorectal cancer are Streptococcus bovis, Helicobacter pylori, Escherichia coli, Bacteroides, and Fusobacterium, etc. The common viruses are Polyomavirus, Epstein Barr virus, Cytomegalovirus and Human papillomavirus, etc. The detailed mechanism of these microorganisms in the pathogenesis of colorectal cancer is unclear, and there are no reports on specific pathogenic microorganisms which cause the disease directly. The direction of future researches will focus on metagenome, metatranscriptome, and metaproteome of microorganisms associated with the incidence of colorectal cancer.