β-连环蛋白在胃癌组织中的表达

THE EXPRESSION OF β-CATENIN IN GASTRIC CARCINOMA

目的了解β-连环蛋白(β-catenin)基因在胃癌组织中的突变情况及其作用。方法以35例新鲜胃癌标本和10例癌旁组织中提取的DNA为模板,采用聚合酶链反应(PCR)-单链构象多态性(SSCP)法对β-catenin的exon3基因突变进行筛选,对筛选阳性标本进行DNA序列测定。采用PV-9000免疫组化两步法检测β-catenin蛋白表达。结果 1例分化不良型胃癌组织中检测到β-catenin exon3基因突变,表现为编码C处单碱基插入突变。癌旁组织β-catenin蛋白连续性表达于细胞膜上;胃癌组织中β-catenin蛋白在细胞膜表达明显减弱甚至消失,7例(20%)在胞浆、胞核内异常蓄积。结论β-catenin基因突变可能不是胃癌肿瘤演进过程中主要的事件。

Objective To study the mutation of β- catenin and its gene and their role in gastric cancer. Methods The DNA selected from 35 fresh specimens of gastric carcinoma and 10 from paraneoplastic tissue served as a template. By using PCR- SSCP method, the mutation of exon 3 of the β catenin gene was screened. For those with positive result, DNA sequence determina tion was conducted. The expression of β catenin was measured by inqmunohistochemical PV-9000 method. Results The β-cate- nin exon 3 mutation was identified in one case with poorly differentiated gastric cancer, manifesting as a single base insertion muta tion. In paracancer tissue, the β-catenin continuously expressed on cell membrane; in cancer tissue, the expression was weaker or even disappeared, abnormal accumulation of β catenin in cytoplasm and nuclei was noted in seven cases （20%）. Conclusion β catcnin mutation is unlikely to be the principal event in the progression of gastric cancer.