结合激光微切割与cDNA芯片技术筛选胃癌进展过程中差异表达的基因

目的:结合激光微切割(LMD)和基因芯片技术筛选胃癌淋巴结转移相关基因,从中进一步确定在胃癌发生和转移过程中都有差异表达的基因。方法:采用LMD技术,从17例胃癌患者手术标本中获取高纯度的正常胃黏膜细胞及原发灶和相应淋巴结转移灶中的肿瘤细胞。用基因芯片比较其中2例原发灶与淋巴结转移灶中肿瘤细胞基因表达谱的差异,半定量RT-PCR方法验证芯片结果;并在另15份标本中,进一步确定在胃癌发生和转移过程中都有差异表达的基因。结果:发现49个基因的表达在胃癌原发灶肿瘤细胞中比淋巴结转移灶明显上调,37个基因的表达明显下调,mRNA水平的验证结果与芯片结果相符。同时,筛选出4个在胃癌发生和转移过程中都有差异表达的基因,其中3个基因(OPCML,RNASE1和YES1)的表达规律与肿瘤抑制基因相似,即正常黏膜中表达最高,肿瘤原发灶次之,淋巴结转移灶表达最低;而另一个基因(AKC1)的表达规律则与癌基因相似。结论:采用LMD和基因芯片技术,成功筛选出胃癌进展过程中的差异表达基因,为进一步研究胃癌发生和转移的机制奠定了良好的基础。

Identification of differentially expressed genes in the gastric cancer patient by laser microdissection and cDNA microarray

Objective: To identify the tumor suppressor and promoter genes that may be involved in gastric carcinoma by comparing the gene expressions in non-malignant gastric epithelia,primary cancer and metastatic lesion in the same patient.Methods: Normal gastric epithelia,primary carcinoma cells and metastatic cells in the lymph nodes were obtained by laser microdissection(LMD) from 17 cases of resected gastric carcinoma with lymph node metastasis.The gene expression profiles were compared between the primary cancer and metastatic lesion by cDNA microarray in 2 of the cases,and the differentially expressed genes were identified by semiquantitative RT-PCR in the other 15.Results: The expressions of 49 genes were obviously up-regulated and 37 down-regulated in primary cancer cells as compared with those in metastatic cells.And the expressions of another 3 genes(OPCML,RNASE1 and YES1) were progressively decreased in the normal,primary cancer and metastatic cells,that is,the highest in the normal cells and lowest in the metastatic ones,but still another gene(AKC1) was expressed just the opposite way in the three types of cells.Conclusion: OPCML,RNASE1 and YES1 genes may serve as candidate tumor suppressor genes and ACK1 as a tumor promoter gene in Chinese gastric carcinoma patients.