2号染色体散发性结直肠癌相关抑癌基因筛选

Tumor suppressor gene screening on chromosome 2 in sporadic colorectal cancer

目的本课题组前期发现散发性结直肠癌2号染色体存在高频杂合缺失现象，提示可能有抑癌基因的存在，本研究拟在该区域筛选与结直肠癌发生相关的抑癌基因。方法构建包含2号染色体高频杂合缺失区域的基因芯片，对19例结直肠癌标本进行表达谱分析，并与临床病理特征加以统计学分析，筛选该区域与结直肠癌相关的未知抑癌基因，然后对筛选出的候选基因采用实时定量聚合酶链反应（Real—timePCR）进行初步验证。结果在前期研究基础上，通过数据库检索，挑选了17个基因进行相关基因筛选。发现ACVRlC在89．47％（17／19）的肿瘤组织中表达下调，其中10例肿瘤组织中下调比例超过2倍。通过Fisher’S精确法分析，ACVRlC的表达与临床病理特征之间无明显相关。在此基础上，通过Real-timePCR验证结果也发现ACVRlC基因的表达与芯片结果相符，在结直肠癌组织中表达显著下调。结论通过表达谱芯片和生物信息学分析，并通过Real—timePCR初步验证，推测ACVRlC基因可能是与结直肠癌发生相关的抑癌基因。

Objective In previous study, we found that there were some high-LOH loci on chro- mosome 2, which indicated that the loci might harbor one tumor suppressor gene that would be associated with colorectal carcinoma. The purpose of this study is to screen for the potential tumor suppressor gene （TSG） on chromosome 2 in Chinese patients with sporadic coloreetal cancer. Methods On the basis of previous our study, we chose 17 genes and presented a microarray-based high throughput screening ap- proach in 19 sporadic eolorectal cancer cases to identify candidate coloreetal cancer related tumor suppres- sor genes. And then, we analyzed the relationship between expression levels of candidate genes and the elinieopathologieal data. Subsequently, real-time quantitative polymerase chain reaction （Real-time PCR） was performed to validate the microarray results. Results According to the microarray-based high through- put screening, we found ACVR1C was significantly down-expressed in the coloreetal cancer tissue compared to its normal mucosal tissue. ACVR1C was down-regulated in 17 out of the 19 cases and it was down-regu- lated over 2-fold in 10 samples. And by Fisher＇ s exact test, there was no significant association between expression levels of ACVR1C and the elinieopathological data. And by Real-time PCR, ACVR1C was down-regulated in colorectal cancer tissue which was coincide to the result of microarray-screening. Con- dusion Through microarray-based high-throughput screening of candidate genes, database searching, and by subsequent Real-time PCR validation, we present the evidence that ACVR1C might be involved in the progression of coloreetal cancer.