【Objectives】 To determine PDX1 gene expression in gastric malignant and the influence of PDX1 upregulation in proliferation and apoptosis of gastric cancer cells. 【Methods】 Gastric cancerous tissue chips were used for detecting PDX1 protein expression by immunohistochemical staining. Three gastric cancer cell lines (AGS

SGC7901

BCG823) were used for detecting PDX1 mRNA and protein level by RT-PCR and Western blotting. Using gastric cancer cells in vitro

effects of PDX1 on cell proliferation and apoptosis after transient transfection with PDX1 vector as well as clone formation and wound healing after stable transfection were assessed. Using xenograft mice in vivo

tumor formation was evaluated. 【Results】 The gastric malignant chip includes 171 adenocarcinomas

12 mucinous adenocarcinoma

6 signet cell cancers

5 undiffernetiated carcinomas

7 malignant stromal tumors

1carcinoid and 8 gastric normal tissues. PDX1 protein was positive in plasma and nuclear of the normal gastric gland cells while absent or significantly down-regulated in gastric cancer (P < 0.05). Compared with normal control

PDX1 mRNA and protein level were also weakly in gastric cancer cell lines. After transient transfection

Ki67 and PCNA were decreased and cleaved-Caspase3 was induced following by PDX1 gene over-expression. Meanwhile

the proliferation index was decreased for 48 hours after transfection and the apoptotic index was increased for 24 hours after transfection. PDX1 overexpression significantly decreased the rates of wound healing

colonal formation and xenotransplanted tumor formation (P < 0.05). 【Conclusion】 This study implies that PDX1 gene is down-regulated in gastric cancerous tissues and cells and is associated with lymphatic metastasis and differentiation. Up-regulation of PDX1 gene inhibits gastric carcinogenesis.