Abstract: Objective：To discuss the expression of miR155 and its clinical significance in gastric carcinoma. Methods：One hundred and sixteen pairs of human gastric carcinoma tissues were obtained from patients who underwent surgical resection. The level of miR155 in 116 gastric cancer tissues and the adjacent normal gastric tissues were detected by realtime fluorescent quantitative reverse transcriptasepolymerase chain reaction (RTqPCR), and the association between miR155 expressions with clinicopathological factors and prognostic values were explored. Immunohistochemical staining for PTEN in all pathological specimens from gastric cancer biopsy was performed. The correlationship between PTEN and miR155 expression was analyzed. Results：The expression of miR155 in gastric cancer tissues was higher than that of adjacent normal gastric tissues (P<0.001). The upregulated expression of miR155 was associated with TNM stage, invasion level and lymph node metastases (P<0.05). KaplanMeier analysis demonstrated that high miR155 expression clearly predicted poorer progression free survival (PFS, P<0.001) and overall survival (OS) (P<0.001) within three years. PTEN expression was negatively correlated to miR155 expression. Gastric cancer tissues with higher miR155 expression disclosed lower PTEN expression (P<0.001). Conclusions：MiR155 may plays a pivotal role in the development and progression of gastric carcinoma, and it may be the potential biomarker in the diagnosis and prognosis of gastric carcinoma.