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目的：进一步精细限定鼻咽癌９ｐ２１－２２区域等位基因杂合性丢失的频率和范围，筛选和克隆其共同缺失区内鼻咽癌相关的候选抑瘤基因。方法：应用１１个定位于 ９ｐ２１－２２区域的高密度微卫星位点，检测 ２５例低分化鼻咽癌患者的杂合性丢失，确定其共同缺失区；用ＲＴ－ＰＣＲ和Ｎｏｒｔｈｅｒｎ筛出在鼻咽癌细胞株ＨＮＥ１和鼻咽癌活检组织中表达下调的、定位于共同缺失区内的 ３’末端ＥＳＴｓ（Ｅｘｐｒｅｓｓ Ｓｅｑｕｅｎｃｅ Ｔａｇｓ）；采用 ＲＡＣＥ技术和生物信息学资源克隆出候选ＥＳＴ的全长ｃＤＮＡ。结果： ２５例患者中有１７例（６８％）存在一个或多个位点的杂合性丢失，其中Ｄ９ｓ１６１（３５．０％，７／２０），Ｄ９Ｓ１６７８（３１．５％，６／１９），Ｄ９Ｓ２６３（３．３％，６／１８）和Ｄ９Ｓ１８５３（３３．３％，７／２１）四个紧邻位点的丢失频率相对较高，并发现六位患者在该四个位点表现为连续性缺失；筛选Ｄ９Ｓ１６１－Ｄ９Ｓ１８５３区域内２５个代表新基因的３’末端ＥＳＴｓ序列，发现一个ＥＳＴ（ｄｂＥＳＴ：２０８８２５）在鼻咽癌细胞株ＨＮＥ１及７３％（１１／１５）的活检组织中表达降低， Ｍｕｌｔｉｐｌｅ Ｔｉｓｓｕｅ Ｎｏｒｔ ｈｅｍ（ＭＴＮ
OBJECTIVE: To further narrow the frequency and range of loss of allelic heterozygosity in 9p21-22 region of nasopharyngeal carcinoma, and to screen and clone candidate tumor suppressor genes associated with nasopharyngeal carcinoma in its common deletion region. Methods: 11 high-density microsatellite loci located in 9p21-22 region were used to detect the loss of heterozygosity in 25 cases of poorly-differentiated NPC. The common deletion region was determined. Phage cancer cell line HNE1 and nasopharyngeal carcinoma biopsy tissue located in the common deletion region 3 ’end ESTs (Express Sequence Tags); RACE technology and bioinformatics resources cloned candidate EST full-length cDNA. RESULTS: Seventeen (68%) of the 25 patients had loss of heterozygosity at one or more loci, of which D9s161 (35.0%, 7/20), D9S1678 (31.5%, 6/19) , The loss frequency of four adjacent sites of D9S263 (3.3%, 6/18) and D9S1853 (33.3%, 7/21) was relatively high, and found that six patients showed continuous at the four sites The deletion of 3 ESTs of 25 new genes in D9S161-D9S1853 region was found. One EST (dbEST: 208825) was found to be down-regulated in nasopharyngeal carcinoma cell line HNE1 and 73% (11/15) of biopsies Multiple Tissue Nort hem (MTN