Immunohistochemical testing for Helicobacter Pylori existence in neoplasms of the colon

BACKGROUND Helicobacter pylori is a common pathogen, and its prevalence varies with socioeconomic conditions (10-80%). It has recently been recognized as a class I carcinogen in relation to gastric cancer. The aim of this study was to investigate the presence of Helicobacter pylori in neoplasms of the colon by immunohistochemical methods. METHODS The polypectomy materials of 51 patients (19 male and 32 female) who had undergone colonoscopic polypectomy were retrieved for retrospective examination. The endoscopic size and colonic localization of the polyps were recorded. Hematoxylin and eosin stains were evaluated according to histological type and grade of dysplasia. Biopsy stains were immunohistochemically treated with Helicobacter pylori antibodies by the streptavidine-biotin immunoperoxidase technique. Helicobacter pylori staining in the gastric mucosa was used as the control for the immunohistochemical method. Specimens were classified according to the presence of Helicobacter pylori under an optical microscope, and Helicobacter pylori positive specimens were stratified according to the respective staining pattern. RESULTS Mean age was 61.88 +/- 10.62 (40-82) years. Polyp sizes were 1.45 +/- 0.92 (1-4) cm; and 25.5% of polyps were localized in the right colon, 68.6% in the left colon and 5.9% in the transverse colon. Presence of Helicobacter pylori was not correlated with localization (p > 0.05) or size of the polyps (p > 0.05).Eleven (21.6%) of all specimens included in the study were Helicobacter pylori positive by immunohistochemical methods. Of the Helicobacter pylori positive specimens, the staining pattern was diffuse: Equivocal in 90.9%, nonspecific with a finely granular type concentrated on the luminal surface in 90.9%, dot-like granular in 54.5%, and spiral in 9.1%. Of the tubular polyps, 17.9% were H. pylori positive, and the staining pattern was equivocal in 100%, luminal in 85.7%, and dot-like granular in 57.1%. Of the villous polyps, 60% were H. pylori positive, and the staining pattern was inconclusive in 66.7%, luminal in 100%, dot-like granular in 33.3%, and spiral in 33.3%. Of the cancerous cases, 25% were H. pylori positive and showed an equivocal, luminal, and dot-like granular staining pattern. No significant correlation was determined between histologic types and prevalence of H. pylori (p > 0.05). CONCLUSION The presence of H. pylori in colon polyps did not yield any correlation with polyp size, colonic localization or histopathologic type. The higher rate of H. pylori positivity in villous polyps does not present a causal relationship. We were able to determine H. pylori existence in colon polyps by immunohistochemical methods, albeit with no statistical significance.