CDNA representation analysis of primary and metastatic colon cans

本研究采用cDNA代表性差异分析（cDNA representation difference analysis， RDA）方法，鉴定在结肠癌肝转移中选择性表达而在原发结肠癌中不表达的候选基因。在以原发癌为“测试者”和过量转移为“驱动者”的RDA中，未见离散条带。在以转移为“测试者”、原发癌为“驱动者”的RDA中，共发现8个候选基因。8个候选基因中有4个与Reg 1α、GW112、Annexin-1和Bax基因序列相同。两个基因被发现是提交给GenBank的基因（一个是在cosmid L219中克隆的基因，另一个是染色体16p13上的基因），尽管这些基因的功能尚不清楚。另外两个克隆与提交给基因库的任何基因都不相同。其中，我们进一步检测了已报道的Reg 1α、Annexin-1和Bax的功能，以及RDA中的优势种GW112的功能。在进一步检查这些基因时，我们发现这些基因的表达并不局限于转移，而是与结肠炎症密切相关。我们在报告中详细展示了Bax基因表达与结肠炎症的关系，以及leg 1α、Annexin-1和GW112基因表达与结肠炎症的关系。

In this study, cDNA representation difference analysis (RDA) was used to identify candidate genes selectively expressed in liver metastasis of colon cancer which are not expressed in primary colon cancer. In RDA with the primary cancer as "tester" and an excess amount of the metastasis as "drivers", no discrete bands were seen. In RDA with the metastasis as "tester" and the primary cancer as "drivers", 8 candidate genes were found. Of 8 candidate genes, four were found to be identical to Reg 1α, GW112, Annexin-1 and Bax by DNA sequencing. Two were found to be the genes submitted to GenBank (one was the gene cloned in cosmid L219 and the other was the gene on chromosome 16p13), although the function of these genes were unkown. The other two clones were not identical to any of the genes submitted to GenBank. Of these, we further examined for Reg 1α, Annexin-1 and Bax functions of which are reported, and for GW112, which is the dominant species in RDA.During further examination of these genes, we found that the expression of these genes were not restricted to metastasis, but closely related to the inflammation of colon. We showed the relation between Bax gene expression and inflammation of the colon and the relation between leg 1α, Annexin-1 and GW112 gene expression and inflammation of the colon in detail in the report.