GENETIC ALTERATIONS AND ALLELIC LOSS IN HUMAN HEPATOCELLULAR CARCINOMA

肝细胞癌是世界上最常见的癌症之一。 亚洲和非洲。在之前的一项研究中，来自启东地区的碳氢化合物 中国经常被发现在抑癌基因P53中发生突变 在16号染色体TAT位点附近的区域。我们已经扩展了这一点 通过检测正常肝组织和肿瘤肝组织的DNA 来自启东和北京的60名患者。我们利用了微卫星 针对16号染色体长臂(或“Q”)的标记。我们的长臂 学期目标是识别和表征新的肿瘤抑制基因 在16号染色体上。 14个高度多态的微卫星标记，定位于 16q21和16q24.3在精细结构分析中的应用 染色体。这些标记的聚合酶链式反应扩增产生两条带 杂合等位基因。如果其中一个显著减少， 肿瘤样本，这表明其中一个等位基因可能缺失。 这种杂合性缺失(LOH)通常是肿瘤的一个指标 缺失区域的抑癌基因。因为肿瘤样本是 通常受到正常组织的污染，定量技术已经 已经开发出来，以允许对 电泳图。这些技术包括分离 由于不完美而出现的重叠卡顿(或阴影)频段 聚合酶链式反应扩增。染色体的破坏被发现是 沿着16号染色体的作图区域延伸。在63对中 样本中，只有11个(175)在任何一个座位上都没有显著的杂合性缺失 已映射。染色体的破坏非常广泛，从50 到85%的样本在每个座位上都显示出可检测到的LOH。 定量分析显示沿线有两到三个“热点”。 杂合子带的相对强度在染色体的哪里 等位基因与侧翼座位的等位基因显著不同。 个人的。这可能表明次级“亚克隆”杂合性缺失，或者 肿瘤组织是多克隆的。这些结果表明了广泛的 16号染色体“Q”臂的染色体断裂，因此 不太可能存在一种新的肿瘤抑制基因 纹身轨迹。不过，通过聚焦上述热点， 我们也许能够定位一个或多个小区域，可能包含 这样的肿瘤抑制基因。

Hepatocellular carcinoma (HCC) is one of the most common cancers in Asia and Africa. In a previous study, HCCs from the Qidong region of China were frequently found mutated in the tumor suppressor gene p53 and in a region near TAT locus on chromosome 16. We have extended this by examining DNA from normal and tumor liver tissue obtained from over 60 patients from Qidong and Beijing. We utilized microsatellite markers specific to the long (or "q") arm of chromosome 16. Our long term goal is go identify and characterize new tumor suppressor genes on chromosome 16. Fourteen highly polymorphic microsatellite markers, mapped between 16q21 and 16q24.3, have been used in fine structure analysis of the chromosome. PCR amplification of these markers produces two bands in heterozygous alleles. If one of these is significantly reduced in the tumor sample, it indicates a potential deletion in one of the alleles. Such loss of heterozygosity (LOH) is often an indicator of a tumor suppressor gene in the deleted region. Because the tumor samples are usually contaminated with normal tissue, quantitative techniques have been developed to allow for quantitative analysis of the electrophoretograms. These techniques include separation of overlapping stutter (or shadow) bands that arise because of imperfect PCR amplification. Chromosomal disruption has been found to be extensive along the mapped region of chromosome 16. Out of 63 paired samples, only 11 (175) showed no significant LOH in any of the loci mapped. The disruption of the chromosome was very broad, with from 50 to 85% of the samples displaying detectable LOH at each of the loci. Quantitative analysis indicated two or three "hot spots" along the chromosome where the relative intensities of bands from heterozygous alleles was significantly different from that of flanking loci in an individual. This may indicate secondary "subclonal" LOH, or that the tumor tissue is polyclonal. These results indicate extensive chromosomal disruption of the "q" arm of chromosome 16, and so make it less likely that there is a new tumor suppressor gene localized near the TAT locus. However, by focusing on the above mentioned hot spots, we may be able to localize one or more small regions that might contain such tumor suppressor genes.