目的　探索人白血病细胞系在裸鼠体内致瘤的分子生物学机制。方法　应用DNA芯片技术 ,检测K5 6 2和K5 6 2 n细胞的基因表达差异。结果　K5 6 2和K5 6 2 n细胞表达差异显著的基因有 139条 ,其中在K5 6 2 n细胞中表达上调的有 4 2条 ,表达下调的有 97条。在这 139条基因中 ,有 85条已在GeneBank中登录 ,5 4条为新序列。这些基因可以划分为 5个主要的功能群 :(1)肿瘤相关基因 ,包括原癌基因和肿瘤抑制基因 ;(2 )与转录调节、细胞周期、凋亡相关的基因 ;(3)与细胞骨架和细胞动力学相关的基因 ;(4)与物质代谢和转运相关的基因 ;(5 )与免疫功能相关的基因。另外还有一些功能混杂的基因和功能未知基因的表达变化。结论　K5 6 2和K5 6 2 n细胞存在多方面基因的表达差异 ,人白血病细胞系K5 6 2 n在裸鼠体内的高致瘤性与其特异的基因表达谱有关。 Objective To explore the molecular mechanism of tumorigenesis of human leukemia cell line in nude mice. Methods DNA microarray technique was used to detect the gene expression difference between K562 and K562n cells. Results There were 139 genes with significant difference between K5 6 2 and K5 6 2 n cells, of which 42 genes were up-regulated in K5 6 2 n cells and 97 genes were down-regulated in K5 6 2 n cells. Of the 139 genes, 85 are registered in GeneBank and 54 are new sequences. These genes can be divided into five major functional groups: (1) tumor-associated genes including oncogenes and tumor suppressors; (2) genes involved in transcriptional regulation, cell cycle, and apoptosis; (3) Genes related to cellular dynamics; (4) Genes involved in substance metabolism and transport; (5) Genes involved in immune function. In addition there are some mixed features of genes and function of unknown gene expression changes. Conclusion The expression of K562 gene in K562 and K562 cells is different from that in K562 cells. The high tumorigenicity of human leukemia cell line K562n in nude mice is related to its specific gene expression profile.