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研究散发性大肠癌中TGF βRⅡ在基因、RNA转录和蛋白表达水平上的改变 ,以及与临床病理参数之间的关系 ,探讨TGF βRⅡ基因突变在大肠癌发生、发展中的作用。 方法 冷冻切片 ,应用免疫组织化学方法检测 40例正常粘膜、癌组织和10例癌旁组织TGF βRⅡ蛋白的表达。应用微解剖技术 ,分离提取 30例正常和癌组织基因组DNA、PCR扩增 ,DNA测序 ,检测TGF βRⅡ基因第 1～ 7外显子的突变。应用微解剖技术 ,分离提取 5例有TGF βRⅡ基因突变的癌组织RNA ,RT PCR扩增 ,2 %琼脂糖凝胶电泳观察TGF βRⅡ基因RNA的表达情况。 结果 TGF βRⅡ蛋白在正常粘膜、癌组织和癌旁组织中的表达率为 85 .0 %、10 .0 %、10 0 %。癌组织中TGF βRⅡ蛋白表达水平与Dukes分期、淋巴结转移呈负相关。 30例癌组织中共检出 10例 (33.3% ) 12处TGF βRⅡ基因突变 ,其中 9例TGF βRⅡ蛋白失表达。随机抽取的 5例有TGF βRⅡ基因突变的病例中均未观察到RNA的表达。在正常和癌组织中 ,均见有第 5外显子 5 39密码子处的变化 (GCT→GTT)。结论 散发性大肠癌组织中存在着较高频率的TGF βRⅡ基因突变 ,以第 6和第 7外显子的点突变为主 ,但在第 3外显子的突变则以缺失为主。大肠癌组织中TGF βRⅡ基因突变 ,可能引起RNA失转录 ,进而导致TGF ?
To investigate the role of TGFβRII gene mutations in the genesis, RNA transcription and protein expression, and the relationship with clinicopathological parameters in sporadic colorectal cancer, to explore the role of TGFβRII gene mutations in the development and progression of colorectal cancer. Methods Frozen sections were used to detect the expression of TGF-βRII protein in 40 cases of normal mucosa, cancer tissues and 10 cases of adjacent tissues by immunohistochemistry. Using micro-anatomical techniques, 30 normal and cancerous genomic DNAs were isolated and extracted, PCR amplified, DNA sequenced, and mutations in exons 1-7 of TGFβRII gene were detected. Using micro-anatomical techniques, 5 cases of cancerous tissue with TGFβRII gene mutations were isolated and extracted. RT PCR was used to amplify and the expression of TGFβRII gene RNA was observed by 2% agarose gel electrophoresis. Results The expression rate of TGF-βRII protein in normal mucosa, cancer tissue and adjacent tissues was 85.0 %, 10.0 % and 1 0 %. The expression of TGFβRII protein in cancer tissue was negatively correlated with Dukes stage and lymph node metastasis. Thirty cases (33.3%) of the 30 cases had cancerous TGF-βRII gene mutations, of which 9 were TGF-βRII protein-less. No RNA expression was observed in 5 randomly selected cases with TGFβRII gene mutations. In both normal and cancer tissues, there was a change in the codon 5:39 exon 5 (GCT→GTT). Conclusion There is a high frequency of TGFβRII gene mutations in sporadic colorectal cancers. Point mutations in exons 6 and 7 are predominant, but mutations in exon 3 are mainly deletions. Mutation of TGFβRII gene in colorectal cancer tissue may cause RNA deactivation, leading to TGF?