Objective To investigate the expression of microRNA (miRNA)-106a in gastric carcinoma and its impact on tumor biological behaviors.Methods The total RNA was extracted from 200 cases of gastric cancer specimens and adjacent tissues,and real-time reverse polymerase chain reaction (RT-PCR) was applied to detect the expression of miR-106a in gastric carcinoma tissues and their adjacent normal tissues.After transfection of miR-106a mimics and miR-106a inhibitors,the expression of cyclindependent kinase (CDK1),a transcription factor (E2F1),tumor suppressor gene (Rb1) and tissue inhibitor of metalloproteinase-2 (TIMP-2) was examined by Western blotting.Methyl thiazol tetrazolium (MTY) assay was used to determine the effect of changes in the expression of miR-106a on gastric cancer cell proliferation.Annexin V-propidium iodide (PI) double staining flow cytometry was used to detect the apoptosis,and Transwell invasion chamber to detect cell invasion.Results The expression of miR-106a in gastric cancer tissues was significantly higher than in adjacent normal gastric tissue.The expression of CDK1 and E2F1 in gastric carcinoma was (1.89 ± 0.23) % and (1.04 ± 0.45) % respectively,significantly higher in miR-106a mimics transfection group than in control group.The expression levels of Rb1 and TIMP-2 in miR-106a mimics transfection group was (0.18 ±0.02)% and (0.41 ±0.09)% respectively,significantly lower than in control group (P < 0.05).MTT results showed that miRNA-106a high expression could promote gastric cancer cell proliferation.Annexin V/PI double staining showed that high expression of miRNA-106a could significantly reduce the apoptosis rate (P < 0.05).Transwell chamber invasion assay showed the apoptosis rate was (9.6 ± 1.5)% after transfection of miR-106a mimics.MiR-106a high expression could improve the invasive ability of gastric cancer cells (P < 0.05).Conclusion The up-expression of miRNA-106a may be associated with the development of gastric cancer. Key words: Gastric cancer; MicroRNA-106a; Prolifation; Apoptosis