ObjectiveTo investigate the changes of XAB2 mRNA and protein expression in gastric cancer tissues, so as to discuss its possible relationship with the development of gastric cancer. MethodsXAB2 mRNA expression in 34 gastric cancer tissues and the matched adjacent normal tissues was examined by real-time RT-PCR. Meanwhile, tissue biochip and immunohistochemistry were employed to examine XAB2 protein expression in gastric cancer tissues, matched adjacent normal tissues, and gastritis tissues. The expression of XAB2 in different tissues and its clinical significance was analyzed. Results XAB2 mRNA expression in the gastric cancer tissues was significantly lower than that in corresponding adjacent normal tissues (P<0.01), and the expression level was greatly decreased at early stage of gastric cancer (stageⅠ+Ⅱ). Immunohistochemical examination showed that the positive rate of XAB2 gene was significantly lower in gastric cancer tissues (50.0%, 17/34) than those in the adjacent tissues (82.4%, 28/34) and gastritis tissues (91.1%, 31/34, P<0.01),with no significant differences found between the latter two tissues. The XAB2 protein expression in gastric cancer tissues was positively correlated to tumor differentiation(P=0.041) and negatively with tumor infiltration and size (P=0.019 and P=0.027, respectively). XAB2 expression was not associated with patients’ sex, age, tumor position, lymph node metastasis or TNM stages(P>0.05). Conclusion The lower XAB2 expression might be closely associated with the development and progression of gastric cancer, and further studying may benefit the diagnosis and therapy of gastric carcinoma patients.