Abstract: Objective To study the mutation of tumor suppressor protein merlin and the expression of ezrin in gastric cancer of Qinghai Tibetan patients, meanwhile to explore the influences of merlin and ezrin on the proliferation and adhesion ability of gastric cancer cell. Method PCR and DNA sequencing was used to analyze the mutation, and the ezrin expression was detected by immunochemical staining. The proliferation and adhesion ability of gastric cancer cell were analyzed by MTT assay. Results The mutation had been detected in merlin gene NF2 exons, and two sites in exon 17 showed high mutation rate, it was more than 50%. Ezrin protein expression was higher in gastric cancer than normal gastric mucosa in Qinghai Tibetan patients（P<0.05）. The expression level of ezrin protein was correlated with the degree of tumor differentiation, lymph node metastasis and histological type of Qinghai Tibetan patients（P<0.05）. Furthermore, the MTT assay showed that FERM domain and merlin-2 had no significant influences on the proliferation and adhesion ability of gastric cancer cell, and ezrin showed no effect on the adhesion ability of gastric cancer cell, but it showed ezrin influenced the cell proliferation. Tumor suppressor protein merlin-1 showed not only a much stronger inhibition of proliferation, but also decreased the cell adhesion ability of gastric cancer cell, and the inhibition of proliferation by merlin was much stronger than ezrin protein. Conclusion The expression of merlin and ezrin is related with the susceptibility to gastric cancer development and metastasis in Qinghai Tibetan patients. Furthermore, merlin-1 and ezrin are involved with adjustment of proliferation and adhesion ability of gastric cancer cell.

Key words: merlin, ezrin, Qinghai Tibetan, gastric cancer, susceptibility