Abstract: Objective：To explore the relationship between the expression of hypoxiainducible factors and clinical features and prognosis of patients with gastric cancer in plateau areas.Methods：62 cases of patients who underwent radical gastric cancer surgery in our hospital from September 2015 to July 2017 were randomly selected.Immunohistochemical staining methods were used to detect the expression of HIF1α protein in gastric cancer tissues and adjacent tissues.Correlation analysis between chemical results and clinical features,using high performance liquid chromatography to detect HIF1α DNA methylation level,and then analyzing the correlation between HIF1αproteinand DNA methylation expression,and then using KaplanMeier Method to analyze the effect of HIF1α proteinexpression on the survival time of patients after surgery.Results：Among the 62 cases of gastric adenocarcinoma and adjacent parts collected,44 cases(70.97%) of gastric cancer parts had upregulated HIF1α factor manifestation levels.The manifestation levels of normal parts and cancer parts were(4.80±0.29) and(3.09±0.09),respectively.There was a imparity between the two(P＜0.05).Statistics of immunohistochemical results showed that the expression level of HIF1α proteinin gastric cancer tissue was not significantly related to the patient's age and gender(P＜0.05).The higher the expression rate of HIF1αmRNA,the larger the tumor,and the high expression rate of HIF1α proteinin gastric body tumors is significantly higher than that of gastric antrum and cardia.Comparing DNA methylation,the expression levels of normal and cancer tissues were(0.158±0.010) and(0.362±0.009),respectively.There was a imparity between the two(t=6.806,P＜0.001).The rate of survivors(HR=0.601,P=0.002) and recurrencefree rate of survivors(HR=0.498,P=0.003) of the HIF1α low manifestation group were dramaticlly higher than these in the HIF1α high manifestation group.onclusion：HIF1α is highly expressed in gastric cancer tissues.It is speculated that it may accelerate the differentiation,expression and metastasis of gastric cancer,and can be used as a reference for determining the prognosis of patients.

Key words: hypoxia inducible factor, gastric cancer, low oxygen environment