Abstract: Objective To investigate the expression of miR-1271-5p in gastric cancer tissues and cells and its effect on cell proliferation，invasion and migration. Methods A total of 90 cases of gastric cancer tissues and corresponding adjacent tissues，surgically resected in Guangxi Medical University Cancer Hospital from June 2011 to June 2014，were collected. The expression of miR-1271-5p in gastric cancer tissues and corresponding adjacent tissues，human gastric cancer cell lines（SGC-7901，MGC-803，AGS）and human normal gastric mucosal epithelial cell line GES1 were detected by qRT-PCR. According to the transient transfection method，miR-1271-5p mimics （overexpressing miR-1271-5p group）and miR-NC（negative control group）were transfected into gastric cancer AGS cells to establish gastric cancer AGS cells overexpressing miR-1271-5p system. The CCK-8 method was used to detect the proliferation ability of gastric cancer AGS cells after transfection，the plate clone formation experiment was used to detect the cell clone formation ability，and the Transwell experiment was used to detect the cell migration and invasion ability. Results The expression of miR-1271-5p in gastric cancer tissues and gastric cancer cells（SGC-7901，MGC-803，AGS）was lower than that in the adjacent tissues and human normal gastric mucosal epithelial GES1 cells（all P<0.01）. Compared with the negative control group，the proliferation activity of gastric cancer AGS cells in overexpressing miR-1271-5p group decreased（P<0.01），the number of cell colony formation and the number of migrating and invading cells also decreased（all P<0.01）. Conclusions miR-1271-5p is lowly expressed in gastric cancer tissues and cells，and up-regulation of miR-1271-5p can inhibit the proliferation，migration and invasion of gastric cancer cell AGS.

Key words: Gastric cancer, miR-1271-5p, Proliferation, Migration, Invasion