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Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 14, 2016; 22(2): 649-658
Published online Jan 14, 2016. doi: 10.3748/wjg.v22.i2.649
Helicobacter pylori and colorectal neoplasia: Is there a causal link?
Vasilios Papastergiou, Stylianos Karatapanis, Sotirios D Georgopoulos
Vasilios Papastergiou, Stylianos Karatapanis, Department of Internal Medicine, General Hospital of Rhodes, 85100 Rhodes, Greece
Sotirios D Georgopoulos, Department of Gastroenterology, Athens Medical, Paleo Faliron General Hospital, 17562 Athens, Greece
Author contributions: Papastergiou V contributed to conception and design, drafting the article; Georgopoulos SD contributed to drafting the article, revising the article critically for important intellectual content; Karatapanis S contributed to final approval of the version to be published.
Conflict-of-interest statement: The authors have nothing to disclose.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Sotirios D Georgopoulos, MD, FEBGH, AGAF, Director, Division of Internal Medicine, Department of Gastroenterology, Athens Medical, Paleo Faliron General Hospital, Areos 36, Paleo Faliron, 17562 Athens, Greece. georgpap@ath.forthnet.gr
Telephone: +30-210-9892100
Received: April 10, 2015
Peer-review started: April 11, 2015
First decision: May 18, 2015
Revised: July 1, 2015
Accepted: September 30, 2015
Article in press: September 30, 2015
Published online: January 14, 2016
Abstract

Ever since Helicobacter pylori (H. pylori) was recognized as an infectious cause of gastric cancer, there has been increasing interest in examining its potential role in colorectal carcinogenesis. Data from case-control and cross-sectional studies, mostly relying on hospital-based samples, and several meta-analyses have shown a positive statistical relationship between H. pylori infection and colorectal neoplasia. However, the possibility exists that the results have been influenced by bias, including the improper selection of patients and disparities with respect to potential confounders. While the evidence falls short of a definitive causal link, it appears that infection with H. pylori/H. pylori-related gastritis is associated with an increased, although modest, risk of colorectal adenoma and cancer. The pathogenic mechanisms responsible for this association remain uncertain. H. pylori has been detected in colorectal malignant tissues; however, the possibility that H. pylori is a direct activator of colonic carcinogenesis remains purely hypothetical. On the other hand, experimental data have indicated a series of potential oncogenic interactions between these bacteria and colorectal mucosa, including induction and perpetuation of inflammatory responses, alteration of gut microflora and release of toxins and/or hormonal mediators, such as gastrin, which may contribute to tumor formation.

Keywords: Helicobacter pylori, Colorectal cancer, Polyp, Adenoma, Gastrin

Core tip:Helicobacter pylori (H. pylori) is a well-recognized gastric carcinogen; however, a causal relationship with colorectal neoplasia remains uncertain. Data from case-control and cross-sectional studies, as well as several meta-analyses, have indicated a significant, although modest, statistical association between infection with H. pylori/H. pylori-related gastritis and the development of colorectal adenomas or cancer. Potential tumorigenic actions of H. pylori to colorectal mucosa include induction of inflammatory responses, alteration of gut microflora and release of toxins and/or hormonal mediators.