Decreased XAB2 Expression And Gastric Cancer

[Objective]To investigate differential mRNA and protein expression of XAB2, to evaluate their association with the pathogenesis and progression of gastric carcinoma, to be benefit for the improvement of the early diagnosis and drug treatment. To explore the role of CpG island methylation in XAB2 gene promoter in the development and progression of gastric carcinoma.[Method]1.34 specimens were obtained from GC patients who had undergone curative surgery at Department of General Surgery of the 1 st affiliated hospital, Second Military Medical University, from November 2007 to July 2009. GC was obtained from nonnecrotic tumor area. The gastric mucosa not continuous with the carcinoma was selected as pathologically normal mucosa. All specimens were frozen in liquid nitrogen immediately after resection and stored at-80oC.14 male and 20 female with GC were included in this study.The range of age was 32-84 and the median was 60.4±12.4.2.The differential mRNA expression of matched normal and carcinoma tissues(n=34) was detected by real-time PCR.3. Tissue biochip and immunohistochemistry were employed to examine the protein levels of XAB2 in the tumor tissues (n=34).4.In order to evaluate the clinical value, Principle of statistics was used to analyze the relationship between expression of XAB2 protein and clinical pathological characteristics of gastric carcinoma patients.3.Real-time PCR was employed to examine the methylation levels of XAB2 gene promoter in gastric carcinoma.[Results]The mRNA expression of XAB2 in normal tissues was significantly higher than that in the primary carcinoma tissues (P< 0.01),while the expression of stageⅠ+Ⅱwas lower than stageⅢ(P< 0.05). Meanwhile, immunohistochemistry showed that the positive rate of XAB2 protein was higher in normal, gastritis tissues than in primary carcinoma tissues(both< 0.01). The expression of XAB2 protein in primary carcinoma tissues was significantly correlated with tumor grades, infiltration and tumor size(P=0.041,P=0.019, P=0.027).There were not significant differences in sex, age, tumor position, lymph node metastasis and TNM stages (P> 0.05). No differential methylation was found significantly in XAB2 gene promoter of gastric carcinoma. [Conclution]XAB2 is lower expressed in gastric carcinoma tissues which is close correlated with the pathogenesis and progression of gastric carcinoma, it may serve as a predicator for diagnosis and treatment of gastric carcinoma patients.