遗传性弥漫性胃癌相关基因表达及突变分析

目的研究遗传性弥漫性胃癌相关基因表达及突变,探讨遗传性弥漫性胃癌家系发病的分子遗传学机制。方法免疫组织化学S-P法检测该家系先证者胃癌组织中E-cadherin、β-catenin、SMAD4、TP53和ANXA10蛋白的表达情况,PCR扩增结合DNA测序筛查E-cadherin、SMAD4、P53和ANXA10基因的所有编码序列以及外显子-内含子交界处序列的种系突变情况。结果与先证者癌旁组织相比,癌组织中E-cadherin、SMAD4、TP53和ANXA10蛋白表达缺失,β-catenin表达降低。检测到SMAD4基因一个新的多态性位点即第1内含子24位碱基出现杂合性AG的改变,E-cadherin基因和ANXA10基因只检测到一些已知多态,未发现种系突变,P53基因未发现任何突变。结论 E-cadherin、β-catenin、SMAD4和ANXA10蛋白异常表达,提示它们可能参与遗传性弥漫性胃癌家系的发病机制,但排除了E-cadherin、SMAD4和ANXA10基因外显子突变导致该病发病的可能性。

Expression and germline mutations screening of related genes in hereditary diffuse gastric cancer

Objective To investigate the expression and germline mutations screening of related genes in hereditary diffuse gastric cancer and to explore the molecular genetics mechanism of hereditary diffuse gastric cancer （HDGC）. Methods Immunohistochemistry S-P method was used to detect the expression of E-cadherin, β-catenin, SMAD4, TP53 and ANXA10 in gastric cancer tissue of proband. Using polymerase chain reaction （PCR）/ sequencing, germline mutations in all coding exons and the intron-exon boundaries of E-cadherin, p53, SMAD4 and ANXA10 were screened. Results Loss of expression of E-cadherin, SMAD4, TP53 and ANXA10 was observed in gastric cancer tissue, the expression of β-catenin was decreased compared with the corresponding adjacent normal tissue. A novel heterozygous germline variation in SMAD4 at position 24（A〉G） in intron 1 was found in proband of this family. Reported polymorphic variation was also found in E-cadherin and ANXA10. No pathogenenic germline mutation was found in E-cadherin, P53, SMAD4 and ANXA10. Conclusion The observed abnormal expression of E-cadherin, β-catenin, SMAD4 and ANXA10 proteins suggests that these molecules might be involved in the carcinogenesis of HDGC, but E-cadherin, SMAD4 and ANXA10 are not likely virulence genes for HDGC.