胃癌组织中caspase-3及其底物DFF45表达的意义

The significance of expressions of caspase-3 and its substrate DFF45 in gastric precancerous lesions and carcinoma tissues

目的观察caspase-3及其底物DNA断裂因子(DNA fragmentation factor,DFF)45在胃癌前状态与胃癌组织中的表达,探讨caspase-3及其底物DFF45在胃癌发生中的生物学意义。方法收集胃镜活检病理石蜡标本280例,其中确诊为慢性萎缩性胃炎(CAG)89例、胃上皮内瘤变(IN)137例、胃癌54例。caspase-3及其底物DFF45蛋白表达分别采用SP法及高压修复抗原方法检测。结果 caspase-3蛋白的阳性表达率在CAG、IN、胃癌组织中分别为68.5%(61/89)、52.6%(72/137)和22.2%(12/54),以CAG最高、胃癌最低(P<0.05);在不同级别IN组织中以高级别最低(P<0.05);在CAG伴与不伴肠化生及胃癌不同分化程度组织中无明显差异(P均>0.05)。DFF45蛋白的阳性表达率在CAG、IN、胃癌组织中分别为64.0%(57/89)、51.1%(70/137)和20.4%(11/54),也以胃癌最低(P<0.05);在各个病理特征组中,caspase-3和DFF45蛋白阳性表达率相互比较差异无统计学意义(P均>0.05);二者共同阳性表达105例,共同阴性表达89例,二者的效度有一定的关联性(k=0.3838,u=9.818,P<0.05)。结论 caspase-3和DFF45蛋白在CAG、低级别IN黏膜中表达上调,而在高级别IN及胃癌组织中表达下调,其在胃黏膜损伤及癌变过程中具有重要生物学意义。

Objective To compare the expressions of caspase-3 and its substrate——DNA fragmentation factor 45（DFF45） in gastric precancerous lesions and carcinoma tissues and explore their biological significance and pathological mechanism of cell apoptosis during progress of gastric carcinoma.Methods A total of 280 cases of archival paraffin embedded specimens of endoscopic biopsy were collected,in which 89 cases were diagnosed as chronic atrophic gastritis（CAG）,137 cases were diagnosed as gastric intraepithelial neoplasia（IN）,and 54 cases were diagnosed as gastric carcinoma.Caspase-3 and its substrate DFF45 were detected by SP method and the pressure cooker antigen repairing method,respectively.Results The positive expression rates of caspase-3 in CAG,IN and gastric carcinoma tissues were 68.5%（61/89）,52.6%（72/137） and 22.2%（12/54） respectively,in which CAG was the highest and gastric carcinoma was the lowest（P0.05）,and the high grade was the lowest in different grades of IN tissues.There were no differences among with or without intestinal metaplasia in CAG tissues and gastric carcinoma tissues of different differentiation degrees（all P0.05）.The positive expression rates of DFF45 protein in CAG,IN and gastric carcinoma tissues were 64.0%（57/89）,51.1%（70/137） and 20.4%（11/54） respectively,in which gastric carcinoma was the lowest too（P0.05）.There were no differences between the positive expression rates of caspase-3 and DFF45 protein in each pathological feature group（all P0.05）.The co-positive expression of caspase-3 and DFF45 protein was 105 cases,and co-negative expression was 89 cases.The expression showed significant correlation（k=0.3838,u=9.818,P0.05）.Conclusions The expressions of caspase-3 and DFF45 protein are up-regulated in the mucosa of CAG and lower grade IN,while down-regulated in high grade IN and gastric carcinoma tissues.The changes present important biological significance in gastric mucosal injury and carcinogenesis.