Association of Helicobacter pylori Infection with Colorectal Cancer

Abstract

Background & Aims: Helicobacter pylori (H. pylori) and stem cell cross-talk are involved in the tumorigenesis of the upper gastrointestinal tract. The aim of this study was to investigate the possible involvement of H. pylori infection in the sequence: chronic inflammation–adenoma–colorectal cancer (cRc) development. Methods: We investigated the following aspects: a. endoscopic and conventional histological examinations of patients with cRc, colorectal adenomas versus controls to detect the presence of H. pylori infection; b. immunohistochemical determination of presence of H. pylori; expression of cD44, indicator of cancer stem cells (cScs) and/or bone marrow-derived stem cells (BMDScs); expressions of oncogene Ki67 and anti-apoptotic Bcl-2 protein; c. expression of cD45, indicator of immune surveillance locally; and d. correlation of the studied parameters with the presence or absence of H. pylori. Results: In 50 patients with cRc, 25 patients with colorectal adenomas and 10 controls, we found significantly higher presence of H. pylori infection in the adenoma (68%) and cRc group (84%) compared with controls (30%). Presence of H. pylori infection with accompanying immunohistochemical expression of cD44 in biopsy specimens was found in a high proportion of patients with colorectal adenomas accompanied with moderate/severe dysplasia (88%) and cRc patients with moderate/severe degree of malignancy (91%). comparable pictures were also obtained for Ki67, Bcl-2 and cD45 immunohistochemical expressions. Conclusion: H. pylori infection by causing a possible chronic inflammatory colon mucosal damage, stimulating cScs or recruiting BMDScs and affecting oncogenes and immune surveillance processes may be involved in the sequence: adenoma – dysplasia – cRc development. Immunogastroenterology 2012; 2:47-56 See related editorial on pages 5-6