Expression of tumor related gene NAG6 in gastric cancer and restriction fragment length polymorphism analysis

AIM: NAG6 gene is a novel tumor related gene identified recently. This study was designed to examine the expression of this gene in gastric cancer and corresponding normal tissues, and to investigate its role in the occurrence and development of gastric cancer, also to study if the genetic structure of NAG6 was altered in gastric cancer.METHODS: Reverse transcription-polymerase chain reaction (RT-PCR), Northern blot analysis and dot hybridization were used to compare the expression level of NAG6 gene in 42 cases of gastric cancer tissues with their corresponding normal tissues of the same patients respectively. In addition,restriction fragment length polymorphism (RFLP) analysis was adopted to study if the genetic structure of NAG6 was altered in gastric carcinomas.RESULTS: The expression of NAG6 in 57.1% gastric cancer tissues (25/42) was absent by RT-PCR analysis. The down-regulation rate of NAG6 in gastric cancer tissues was significantly higher than that in corresponding normal tissues(P<0.01). However no correlation between the down-regulation of NAG6 and lymph-node and/or distance metastasis was found in this study (P>0.05). Dot hybridization confirmed the results of RT-PCR. Furthermore,the results of EcoRI RFLP analysis of NAG6 gene demonstrated that 3 of 7 cases of gastric cancer showed loss of 5 kb fragment in comparison with their corresponding normal tissues.CONCLUSION: NAG6 gene is significantly down regulated in gastric cancer. The loss of genetic materials may be the cause of down-regulation of NAG6 expression. This seems to suggest that NAG6 may represent a candidate of putative tumor suppressor gene at 7q31-32 loci associated with gastric carcinoma. The down-regulation of this gene may play a role in occurrence and development of this disease, however it may not be associated with lymph node and/or distance metastasis.

肿瘤相关基因NAG6、NAG-7、BRD7在胃癌中的表达

目的 NAG6、NAG 7、BRD7为最近克隆的肿瘤相关新基因 ,对它们在胃癌及癌旁组织中的表达进行检测 ,探讨这些基因在胃癌发生发展中的作用。方法 采用RT PCR、Northern杂交、点杂交方法检测 34例胃癌和癌旁组织中这些基因的表达。结果 胃癌组织中 ,有 61 .8% (2 1 / 34)NAG6基因表达缺失 ,NAG6在胃癌组织中的表达较癌旁组织显著下调 (P <0 .0 1 ) ,但NAG6表达下调与胃癌淋巴结或远处转移无明显关系 (P >0 .0 5)。NAG 7基因在胃癌和癌旁组织中表达率分别为 88.2 % (30 / 34)和 82 .3 % (2 8/ 34)。BRD7基因在胃癌及癌旁组织中均有表达。RT PCR、Northern杂交、点杂交结果均显示NAG 7、BRD7基因在胃癌与癌旁组织之间的表达差异无显著性。同时 ,点杂交也证实NAG6在胃癌组织中表达下调。结论 NAG6基因在胃癌组织中表达显著下调 ,这可能在胃癌的发生发展过程中起重要作用 ,但可能与淋巴结或远处转移无关。BRD7、NAG 7基因在胃癌中未发现表达水平改变 。