ABSTRACT
Background: Gastric cancer is one of the most significant reasons for cancer-related death. miR-146a is one of the dysregulated factors associated with gastric tumorigenesis. However, deregulation of this microRNA (miRNA) has become controversial. Moreover, the inflammation-mediating role of this miRNA implies that miR-146a might be dysregulated by gastric cancer-related pathogens, such as Helicobacter pylori. However, the dysregulation of miR-146a in H. pylori-infected gastric tumors has not been widely studied. Objectives: We aimed to analyze the expression level of miR-146a in gastric cancer tissues and then to assess any potential association between miR-146a and H. pylori infection and other clinical characteristics. Materials and Methods: miR-146a expression level was quantitatively studied by reverse transcription quantitative polymerase chain reaction, in 144 fresh tissues including 44 normal and 100 gastric cancer samples. Results: A dramatic overexpression of miR-146a was observed in primary gastric tumors. miR-146a showed lower expression in progressed tumors with greater stages and lymph node metastasis. Conclusion: miR-146a is highly expressed in primary gastric tumor independent of H. pylori infection. It is highly expressed in the lower stages and lymph node-negative tumors. It might suggest the importance of upregulation and downregulation of this miRNA in the initiating/promoting and progressive steps of gastric tumorigenesis, respectively