散发性结直肠癌染色体5q14区杂合性缺失精细定位

Refinement of heterozygosity loss on chromosome 5q14 in sporadic colorectal cancer

目的:研究散发性结直肠癌五号染色体杂合性缺失,对5q14区精细定位,寻找新的结直肠癌抑癌基因。方法:五号染色体采用16个微卫星DNA标记,在5q14区另取7个微卫星标记对83例结直肠癌病例的肿瘤和正常组织进行PCR反应。PCR产物在ABI Prism377自动荧光测序仪进行电泳3小时,以GeneScan3.1和Genotyper 2.1软件进行基因分型。结果:在五号染色体上发现了三个高频杂合缺失区即5p15、5q14和5q22区。对5q14区再用7对微卫星标记引物行精细定位,界定了三个精细的高频杂合缺失区域。结论:通过精细杂合缺失作图研究,在5q14区发现三个精细的杂合缺失区域,该区很可能存在一个或多个与结直肠癌相关的新的抑癌基因。

Objective：To refine the loss of heterozygosity（LOH） on chromosome 5q14 and identify the new tumor suppressor gene（s） in colorectal tumorigenesis.Methods： Sixteen polymorphic microsatellite markers were analyzed on chromosome 5 and another 7 markers were applied on chromosome 5q14 in 83 cases of colorectal and normal DNA by PCR.PCR products were eletrophoresed on an ABI 377 DNA sequencer.Genescan 3.1 and Genotype 2.1 software were used for LOH scanning and analysis.Results： We observed 3 distinct regions of frequent allelic deletions on chromosome.Another 7 polymorphric microsatellite markers were applied to 5q14 and three minimal regions of frequrent loss of heterozygosity was established on 5q14.Conclusion： Through our detailed deletion mapping studies,we have found three critical and precise location of 5q14,which must contain one or more unknown tumor suppress or gene（s）on colorectal cancer.