Zhang Xiao-Mei, Wang Xiao-Yan, Sheng Shou-Rong, Wang Jie-Ru, Li Jiang
Department of Digestion Medicine, The Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China.
World J Gastroenterol. 2003 Aug;9(8):1729-33. doi: 10.3748/wjg.v9.i8.1729.
NGX6, NAG-7 and BRD7 genes are tumor related genes, which have been newly cloned by positional candidate cloning strategy. This study was designed to investigate the expression levels of NGX6, NAG-7 and BRD7 genes in human gastric and colorectal cancer tissues, and their corresponding normal tissues, and to investigate whether these genes play a role in the pathogenesis of gastric and colorectal cancers.
Reverse transcription-polymerase chain reaction (RT-PCR), dot hybridization and Northern blot analysis were used to compare the expression levels of NGX6, NAG-7 and BRD7 genes in 34 gastric cancer tissues and 34 colorectal cancer tissues with their corresponding normal tissues of the same patients, respectively.
Among the 34 colorectal cancer specimens and the 34 gastric cancer specimens, the expression of NGX6 in 25 colorectal cancer tissues was absent or very weak (73.5 %) by RT-PCR analysis. The down-regulation rate of NGX6 in colorectal cancer tissues was significantly higher than that in corresponding normal tissues (26.5 %,9/34) (P<0.005). Moreover, the down-regulation of NGX6 was significantly correlated with lymph node and/or distance metastases. Patients with lymph node and/or distance metastasis had much higher down-regulation rate of NGX6 than patients without metastases (93.8 % vs 55.6 %, P<0.05). However no correlation was found between the expression of NGX6 and pathologic type of colorectal cancer in this study, and also the expression of NGX6 did not display any difference between gastric cancer and corresponding normal tissues (58.8 % vs 70.6 %, P>0.25). Dot hybridization and Northern blot analysis confirmed the results of RT-PCR. Furthermore, NAG-7 and BRD7 mRNA was not up- or down-regulated in gastric and colorectal cancers compared with their corresponding normal tissues in our study.
The down-regulation of NGX6 may be closely associated with tumorigenesis and metastasis of colorectal carcinoma. However, it may not contribute to the development and progression of gastric carcinoma. In addition, the expression levels of NAG-7, and BRD7 did not alter in gastric and colorectal cancers. This seems to suggest that NAG-7 and BRD7 genes may not play a role in gastric and colorectal carcinogenesis.
NGX6、NAG - 7和BRD7基因是肿瘤相关基因，采用定位候选克隆策略新克隆得到。本研究旨在检测NGX6、NAG - 7和BRD7基因在人胃癌和结直肠癌组织及其相应正常组织中的表达水平，并探讨这些基因是否在胃癌和结直肠癌的发病机制中发挥作用。
分别采用逆转录 - 聚合酶链反应（RT - PCR）、斑点杂交和Northern印迹分析，比较34例胃癌组织和34例结直肠癌组织及其同一患者相应正常组织中NGX6、NAG - 7和BRD7基因的表达水平。
在34例结直肠癌标本和34例胃癌标本中，RT - PCR分析显示25例结直肠癌组织中NGX6表达缺失或非常弱（73.5%）。结直肠癌组织中NGX6的下调率显著高于相应正常组织（26.5%，9/34）（P<0.005）。此外，NGX6的下调与淋巴结和/或远处转移显著相关。有淋巴结和/或远处转移的患者NGX6下调率远高于无转移患者（93.8%对55.6%，P<0.05）。然而，本研究未发现NGX6表达与结直肠癌病理类型之间存在相关性，且NGX6在胃癌组织与相应正常组织中的表达也无差异（58.8%对70.6%，P>0.25）。斑点杂交和Northern印迹分析证实了RT - PCR结果。此外，在本研究中，与相应正常组织相比，NAG - 7和BRD7 mRNA在胃癌和结直肠癌中未上调或下调。
NGX6的下调可能与结直肠癌的发生和转移密切相关。然而，它可能与胃癌的发生和发展无关。此外，NAG - 7和BRD7在胃癌和结直肠癌中的表达水平未改变。这似乎表明NAG - 7和BRD7基因可能在胃癌和结直肠癌的发生过程中不起作用。
