Q1. Correct Answer: C
Rationale
The CagA strain of H. pylori has been found to be associated with an increased risk of gastric adenocarcinoma and MALT lymphoma. CagA-producing H. pylori infection also cause more severe mucosal inflammation and is associated with higher incidences of gastric and duodenal ulcers. A protective effect of CagA+ H. pylori against gastroesophageal reflux disease, reflux esophagitis, Barrett's esophagus, and esophageal adenocarcinoma has been suggested, as some epidemiologic studies have shown a decreased prevalence of these disorders. Although further studies are needed to verify these relationships, no studies to date have demonstrated an increased risk of esophageal carcinoma associated with H. pylori. CagA-producing H. pylori has not been associated with gastric carcinoid tumor.
References
1. Fallone CA, Barkun AN, Göttke MU, et al. Association of Helicobacter pylori genotype with gastroesophageal reflux disease and other upper gastrointestinal diseases. Am J Gastroenterol. 2000;95(3):659-69.
2. Huang JQ, Zheng GF, Sumanac K, et al. Meta-analysis of the relationship between cagA seropositivity and gastric cancer. Gastroenterology 2003;125(6):1636-44.
3. Islami F, Kamangar F. Helicobacter pylori and esophageal cancer risk: a meta-analysis. Cancer Prev Res. 2008;1:329-38.
