胃癌差异表达基因的克隆测序及临床应用

目的 筛选数个在胃癌及癌前病变中检出率高的胃癌差异表达片段。方法 以筛选了的gcys-10,gcys-12,gcys-13,gcys-16这4个新基因片段为研究对象，将它们克隆入T载体中进行测序，根据序列设计引物，采用RT－PCR方法检测胃癌细胞株GC7901、胃粘膜细胞株GES－1以及胃癌、胃粘膜活检标本。结果 4个差异基因表达片段测序后经过同源性检索均为新基因，被基因库收录，收录呈为AF054171，AF071052，071053,某某071056。根据这些基因设计的4对引物均能从GC7901总RNA中扩增出相应产物，而gcys-10的引物未能从GES－1细胞株中扩增出相应产物。gcys-10在50例活检标本中的检出率分别为：萎缩性胃炎83.3%，肠腺化生81.8%，疣状胃炎58.3%，胃癌88.9%，胃溃疡50.0%，十二指肠溃疡0，急性胃炎0。在17例胃癌手术标本的检出率为94.1%。结论gcys-10,gcys-12,gcys-13,gcys-16均为胃癌差异表达基因，其中gcys-10在胃癌及胃癌前病变中检出率非常高，其表达的变化可能对胃癌的早期发展有意义。

Cloning, sequencing and clinical application of differentially expresse d genes in gastric cancer

AIM To screen some genes, which were differen tially expressed with higher examination rates in stomach neoplasms and in precancerous pathological changes. METHODS Four differentially expressed genes in gastric cancer were selected. They were gcys 10, gcys 12, gcys 13 and gcys 16. These fragments were cloned into T vector, then sequenced directly. The obtained sequences were searched against GenBank. Primers were designed according to the obtained sequences. RT PCR was used to examine clinical samples. RESULTS Four sequences new and were all accepted by GenBank. Their accepted numbers were AF054171, AF071052, AF 071053 and AF071056. The target products could be amplified by all the four pairs of RT PCR primers in GC7901, but they could not be amplified by the pair of RT PCR primers of gcys 10 in GES 1. So the primers of gcys 10 were applied clinically. The expression rates of gcys 10 in the biopsy specimens of gastric mucosa were:83.3% in atrophic gastritis, 81.8% in metaplasia of intestinal glands, 58.3% in verrucous gastritis, 88.9% in gastric cancer, 50.0% in gastric ulcer and 0 in duodenal ulcer and acute gastritis respectively. The expression rate of gcys 10 in the histo specimen of gastric cancer was also 94.1% in 17 cases. CONCLUSION gcys 10, gcys 12, gcys 13, gcys 16 are all differentially expressed genes in gastric cancer. Four sequences are all accepted by the GenBank. The expression rate of gcys 10 is different in gastric cancer from that in gastritis. Study of the expression rate of gcys 10 may help establish the alarming system of gastric cancer.