Abstract: ObjectiveTo investigate the expression of SMARCA1 and clarify the clinical significance and prognostic value of SMARCA1 of gastric cancer in the Gene Expression Omnibus（GEO） and The Cancer Genome Atlas（TCGA） datasets. 
MethodsSMARCA1 expression and its clinical information were downloaded from GEO and TCGA datasets. The influence of SMARCA1 expression on clinical pathological factors and overall survival（OS） were analyzed and gene set enrichment analysis（GSEA） was used to predict the SMARCA1related related gene signaling pathway. 
ResultsThe expression of SMARCA1 was associated with T stage in GSE62254 dataset（P=0022）， but not related to gender， age， TNM stage and N stage in GSE62254（P＞005）. In TCGA dataset， SMARCA1 was not related to gender， age， TNM stage， T stage, N stage and histology classification. In the aspect of survival analysis， the median OS of high， medium and low levels of SMARCA1 expression were 364 months， 894 months and not achieved in GSE62254（P=0001）； the median OS of high， medium and low levels of SMARCA1 expression were 237 months， 294 months and 562 months in TCGA（P=0033）. GSEA showed that the expression of SMARCA1 could regulate gene sets involving KRas， Akt， BMI1 and mTOR signaling pathway. 
ConclusionSMARCA1 was related to T stage in gastric cancer， and its high expression was associated with poor prognosis. It could be a polential molecular marker for evaluating the prognosis of gastric cancer.

Key words: Gastric cancer, Gene Expression Omnibus（GEO）, The Cancer Genome Atlas（TCGA）, SMARCA1, Prognosis