Q1. Correct Answer: C
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.
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