Aquaporin 3 Expression Pattern in Gastric Diseases and its significance

Abstract Background Aquaporin 3(AQP3) has been implicated in gastric intestinal metaplasia and gastric cancer, and considered as a biomarker to improve treatment strategy. Accumulating evidence suggests that AQP3 is involved in the gastric carcinogenesis and the disease progression. However, whether AQP3 is involved in the transformation from gastritis to gastric cancer remain elusive. In this study, we intended to realized the expression pattern and its significance of AQP3 in different gastric diseases. Methods A total of 101 patients diagnosed with gastric diseases were included in the study. A gastric tissue biopsy was taken from the gastric antrum during endoscopic examination. Expression of AQP3 protein is determined by immunohistochemistry using polyclonal rabbit anti-AQP3 antibody. Percentage of positive cells and staining intensity were counted and measured. Results The frequency of AQP3 positivity was similar between the disease types of chronic gastritis, gastric ulcer, gastric erosion, and atrophic gastritis, whereas the frequency of AQP3 positivity was significantly higher in patients with gastric intestinal metaplasia、gastric dysplasia 、gastric polyps and intestinal-type gastric adenocarcinoma than that in patients with gastritis, gastric ulcer, gastric erosion, or atrophic gastritis(p<0.0001, p=0.001, p=0.006, p=0.0009, respectively), especially in the patients with hyperplastic polyps (p<0.0001). Conclusion The frequency of AQP3 positivity was significantly higher in patients with gastric intestinal metaplasia, gastric dysplasia, and gastric adenocarcinoma, and the frequency between them was similar, suggesting that AQP3 expression is peaked at the stage of gastric intestinal metaplasia, which further confirmed that gastric intestinal metaplasia is a pivotal progression in gastric carcinogenesis pathologically. Interestingly, it is the first time to report AQP3 positive expression in patients with gastric polyps. In short, AQP3 is involved in the progression from gastritis to gastric adenocarcinoma, and might be a potential biomarker to improve the treatment strategy of gastric cancer.