Infectious Agents and Colorectal Cancer: A Review of Helicobacter pylori, Streptococcus bovis, JC Virus, and Human Papillomavirus

Department of Epidemiology, School of Public Health and Community Medicine, University of Washington, 1100 Fairview Avenue North, M4-B402, Seattle, WA 98109, USA.
Cancer Epidemiology Biomarkers & Prevention (Impact Factor: 4.32). 12/2008; 17(11):2970-9. DOI: 10.1158/1055-9965.EPI-08-0571
Source: PubMed

ABSTRACT Based on the high volume of bacteria and viruses that the intestine is exposed to and the importance of infectious agents in some gastrointestinal and anogenital cancers, it is not surprising the many studies have evaluated the association between colorectal cancer and infectious agents. This review highlights investigations of four agents in relation to colorectal cancer. Helicobacter pylori, Streptococcus bovis, JC virus, and human papillomavirus have all been evaluated as possible etiologic agents for colorectal cancer. For each of these agents, a review of possible mechanisms for carcinogenesis and epidemiologic evidence is discussed, and future directions for research are proposed.

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    ABSTRACT: Streptococcus bovis is a Gram-positive bacterium causing serious human infections, including endocarditis and bacteremia, and is usually associated with underlying disease. The aims of the current study were to compare prevalence of the bacterium associated with malignant and nonmalignant gastrointestinal diseases and to determine the susceptibility of the isolated strains to different antimicrobial agents. The result showed that the prevalence of S. bovis in stool specimens from patients with malignant or with nonmalignant gastrointestinal diseases was statistically significant. This result may support the idea that there is correlation between S. bovis and the malignant gastrointestinal diseases.
    International Journal of Microbiology 10/2011; 2011:792019. DOI:10.1155/2011/792019
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    ABSTRACT: Colorectal cancer (CRC) is the second most common cause of cancer mortality among men and women worldwide; the risk of its occurrence has been shown to be increased by chronic bacterial infections. A case control study was therefore carried out at Hospital Universiti Sains Malaysia (HUSM) to determine the incidence of colorectal cancer associated with S. bovis infection. A total of 166 stool specimens were collected from diseased patients and healthy individuals and S. bovis isolates were identified. Suspected colon tumor and cancer cases were diagnosed and confirmed. It was found that overall prevalence of S. bovis was 41 (24.7%) out of 166 cases studied. Some 41(48.6%) of these S. bovis isolates was found in patients with colonic polyps, adenocarcinomas, inflammatory bowel disease (IBD) and chronic gastrointestinal tract (GIT). It was also found that colorectal cancer incidence was 24.7%, adenocarinomas accounting for 51% with the highest incidence in the sigmoid part of the colon. Among the IBD and chronic GIT cases, ulcerative colitis featured in the majority of cases (41.4%). In conclusion, there is a high incidence of colorectal cancer associated with S. bovis.
    Asian Pacific journal of cancer prevention: APJCP 01/2010; 11(6):1765-8. · 1.50 Impact Factor
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    ABSTRACT: To prospectively examine the association between presence of Streptococcus bovis (S. bovis) in colonic suction fluid and the endoscopic findings on colonoscopy. From May 2012 to March 2013, 203 consecutive patients who underwent colonoscopy for any reason were enrolled in the study. Exclusion criteria included: antibiotic use in the previous month, age younger than 18 years, and inadequate preparation for colonoscopy. The colonoscopy was performed for the total length of the colon or to the occluding tumor. The endoscopic findings were registered. Samples were obtained proximal to the colonoscopic part of the suction tube from each patient and sent to the clinical microbiology laboratory for isolation and identification of S. bovis. Samples were incubated in enrichment media with addition of antibiotic disks for inhibition of growth of Gram-negative rods. The samples were seeded on differential growth media; suspected positive colonies were isolated and identified with Gram staining, catalase, and pyrrolidonyl arylamidase tests, and further identified using a VITEK2 system. Statistical analyses were performed using the Student's t and χ(2) tests. Of the 203 patients recruited, 49 (24%) patients were found to be S. bovis carriers; of them, the endoscopic findings included: 17 (34.7%) cases with malignant tumors, 11 (22.4%) with large polyps, 5 (10.2%) with medium-sized polyps, 6 (12.2%) with small polyps, 4 (8.1%) with colitis, and 6 (12.2%) normal colonoscopies. Of 154 patients found negative for S. bovis, the endoscopic findings included: none with malignant tumors, 9 (5.8%) cases with large polyps, 11 (7.1%) with medium-sized polyps, 26 (16.9%) with small polyps, 7 (4.5%) with colitis, and 101 (65.6%) normal colonoscopies. S. bovis (Gram-positive coccus) is considered part of the normal intestinal flora. There is an association between S. bovis bacteremia and colonic neoplasia. It is not well understood whether the bacterium has a pathogenetic role in the development of neoplasia or constitutes an epiphenomenon of colorectal neoplasms. There was a clear relationship between positivity for S. bovis in colonic suction fluid and findings of malignant tumors and large polyps in the colon. There is an association between S. bovis bacteremia and malignant colonic lesions; this should prompt for development of a reliable screening method for advanced colonic lesions.
    05/2015; 21(18):5663-7. DOI:10.3748/wjg.v21.i18.5663


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