Colorectal cancer (CRC) is one of the leading causes of cancer-related mortality worldwide. In the Unites States, an estimated 151,300 Americans will be diagnosed with CRC and over 52,580 are expected to die from the disease in 2022 alone (https://seer.cancer.gov/statfacts/html/colorect.html). While the five-year survival rate for localized CRC is excellent at 90%, more than half of new CRC cases have the disease spread to regional lymph nodes and/or distant organs at the time of diagnosis. CRC with distant metastasis has a dismal five-year survival rate of 14.7%. These data clearly indicate that CRC-related mortality can be significantly improved if the disease is detected early and proper interventions could be deployed. Because CRC typically originates from precancerous colorectal polyps, routine colonoscopy screening provides an excellent opportunity to detect precursor or early lesions and reduce CRC-related morbidity and mortality. Indeed, the US Preventive Services Task Force recently updated its recommendation on CRC screening, noting the evidence that the screening in average-risk asymptomatic adults aged 50 to 75 years is of substantial benefit. Risk factors for CRC include age (>50), race (African American), obesity, cigarette smoking, type II diabetes, history of inflammatory bowel diseases, family history of colorectal polyps or CRC, and inherited genetic syndromes known to increase the CRC risks, such as familial adenomatous polyposis (FAP) and Lynch syndrome. FAP and Lynch syndrome are caused by germline mutations in the APC gene and DNA mismatch repair genes, respectively. The management of individuals with hereditary gastrointestinal cancer syndromes requires additional measures beyond what is recommended for the average-risk population to minimize the overall risk of cancer-associated morbidity and mortality. Management options for the confirmed mutation carriers include multiple aggressive screening, chemopreventive strategies, and prophylactic surgery. However, these interventions are associated with various degrees of adverse effects. Safer and more effective preventive measures are urgently needed for the individuals with FAP, Lynch syndrome, and other hereditary gastrointestinal cancer syndromes. Fusobacteria are common human oral gram-negative anaerobic microflora isolated from dental plaque and gum diseases, but rarely detectable in the colorectum of healthy individuals. In recent years, the enrichment of a specific pathotype, Fusobacterium nucleatum (Fn), has been demonstrated in the colonic tissues and stools from patients with colorectal adenomas and CRC. Clinical evidence suggests that the prevalence of Fn progressively increases from dysplasia, adenomas to CRC and the higher amount of Fn is significantly associated with CRC with high microsatellite instability, which is caused by DNA MMR deficiencies as seen in Lynch syndrome-associated CRC. The potential association of Fn with CRC tumorigenesis has been examined in ...