胰癌组织p15、p16抑癌基因CpG岛甲基化

目的:检测胰腺癌中p15、p16基因CpG岛的异常甲基化情况,分析其与胰腺癌发生、发展的关系;探索其在临床早期基因诊断和治疗中的意义以及与胰腺癌病理生理特征的相关性.方法:运用甲基化特异性PCR(methylation-specific PCR,MSP),对29例胰腺癌和3例慢性胰腺炎的石蜡组织、2例正常肝组织、以及12例正常成人外周血白细胞DNA的p15、p16抑癌基因启动子区CpG岛甲基化状态进行了检测.结果:对照组p16、p15基因CpG岛甲基化扩增均呈阴性,非甲基化扩增均阳性.胰腺癌中p16、p15基因CpG岛甲基化阳性率分别为37.9%和27.5%,p16、p15基因CpG岛甲基化总检出阳性率为:44.8%.癌组织中同时存在p16、p15基因CpG岛异常甲基化为6例.结论:胰腺癌p15、p16基因CpG岛甲基化是早期事件,可试作为早期基因诊断的分子标志,有可能尝试进行基因治疗.p16、p15基因CpG岛异常甲基化,同患者的病理特征无明显的相关关系.

Objective: To investigate whether deletion of chromosome 17 is involved in the carcinogenesis of primary glioblastoma multiforme and to localize the possible common deletion region in the aforementioned chromosome. Methods: Polymerase chain reaction-based microsatellite analysis was used to assess loss of heterozygosity (LOH) on chromosome 17 in 20 primary glioblastoma multiforme (GBM). Fifteen fluorescent dye-labeled polymorphic markers were used. Results: Thirteen of twenty (65%) GBM displayed LOH on at least one marker of chromosome 17p. Two tumors showed either LOH or non-informativeness on all markers tested. The most frequent LOH was observed at loci including D17s799 (53.3%), Dl7s1852 (53.8%), Dl7s938 (63.20/o), Dl7s831 (55.6%). The loci D17s831 (on 17pl3) and D17s799(Dl7sl852 (17p11.2(pl2) are distal and proximal to p53 respectively. The frequencies of LOH at all loci examined on chromosome 17q were relatively low (<30%). None of informative loci exhibited microsatellite instability in this study. Conclusion: Loss of genetic material on chromosome 17p may play an important role in the pathogenesis of GBM. Besides the well-known TSG p53 on 17p, other unknown TSCs associated with GBM may be present on the chromosomal regions 17pl3 and 17p11.2(pl2, which are distal and proximal to p53 respectively.

Objective: This study was designed to clone candidate tumor suppressor genes down-expressed in Nasopharyngeal Carcinoma (NPC). Methods: Differentially expressed cDNA fragments (AF152605 and AF091517) were labeled by PCR, and Northern blot was used to confirmed transcript length of these genes. Skeleton muscle cDNA library was screened with PCR-labeled probe mixture. By sequencing the positive clones directly, three novel genes (Genbank accession number: AF179285, AF170307 and AF194971), with transcripts of 2.1 Kb, 1.1 Kb and 1.4 Kb respectively, were isolated successfully. Conclusions: Library screening using PCR-labeled probes mixture is an efficient method to get full-length cDNA from multi-cDNA fragment simultaneously and quickly.

1 IntroductionRecent progress in molecular biology has enabled us to better understand the molecular mechanism underlying pathogenesis of human malignancy including lung cancer. Sequencing of human genome has identified many oncogenes and tumor suppressor genes,giving us a better understanding of the molecular events leading to the formation, progression, metastasis, and the development of drug resistance in human lung cancer. In addition, many signal transduction pathways have been discovered that play important roles in lung cancer. Novel strategy of anti-cancer drug development now involves the identification and development of targeted therapy that interrupts one or more than one pathways or cross-talk among different signal transduction pathways. In addition, efforts are underway that combine the traditional cytotoxic (non-targeted) agents with the biological (targeted) therapy to increase the response rate and survival in patients with lung cancer, especially advanced non-small cell lung cancer (NSCLC).