Purpose To investigate the expression of pro-tein of relevant evolutionary and lymphoid interest domain-con-taining 1(PRELID1)in gastric cancer tissues and to analyze its effect on prognosis,and the mechanism of influencing the prolif-eration and invasion ability of gastric cancer cells.Methods Using TCGA data and clinical data of 111 patients with gastric cancer,we analyzed the relationship between the expression of PRELID1 and clinicopathological parameters and the impact on clinical prognosis.The biological function of PRELID1 was pre-dicted by bioinformatics,and further verified by in vitro and in vivo experiments.Lentivirus was applied to regulate the level of PRELID 1 in gastric cancer cell line(MGC803)in vitro,and its effect on the proliferation,migration,and invasion of gastric cancer cells was observed.The nude mouse subcutaneous tumor-igenesis was used to observe the effect of PRELID1 on the growth of gastric cancer tissue in vivo.Results The expression of PRELID1 was significantly higher in gastric cancer tissues than that in the adjacent tissues(P＜0.001)and was positively cor-related with the cell proliferation indicator Ki67(P＜0.001).Cox regression model analysis showed that the high expression of PRELID 1 was an independent risk factor affecting the 5-year survival rate after radical gastrectomy(HR=2.336;95％CI=1.354-4.029).Gene enrichment results showed that the func-tion of PRELID1 was related to proliferation and JAK/STAT sig-naling.CCK-8 and Transwell experiments found that up-regula-tion of PRELID1 promoted the proliferation(P=0.016),mi-gration(P=0.016)and invasion(P=0.025)of gastric cancer cells,while down-regulation inhibited the proliferation(P=0.026),migration(P=0.048)and invasion(P=0.029).Subcutaneous tumor formation experiments in nude mice found that up-regulation of PRELID1 promoted the growth of gastric cancer tissue(P=0.047),while down-regulation was the oppo-site(P=0.005).Western blot detecting gastric cancer cells and gastric cancer tissues found that up-regulation of PRELID1 promoted the expression of JAK and STAT proteins(all P＜0.05),while down-regulation inhibited them(all P＜0.05).Conclusion The high expression of PRELID1 associated with poor prognosis may regulate the proliferation,migration and in-vasion of gastric cancer cells by up-regulating JAK/STAT signa-ling in gastric cancer.