Analysis of p53 tumor suppressor gene and MDM2 gene in solid tumors in childhood.

P53基因经常受到点突变或缺失的影响，这些突变或缺失导致了各种成人实体肿瘤的发生和发展。神经母细胞瘤是一种常见的儿童交感神经系统恶性肿瘤。然而，据我们所知，这种基因改变在神经母细胞瘤中很少被分析。在这个项目中，我们从36例原发神经母细胞瘤的石蜡包埋块中提取基因组DNA样本。我们筛查了p53基因外显子5-8的突变，据报道，超过90%的突变位于人类癌症中。我们还检测了K-ras和N-ras基因的突变，这两种基因与许多肿瘤有关。筛查技术采用聚合酶链式反应/单链构象多态分析(PCR-SSCP)，并通过序列分析进一步证实了潜在的突变，因此，无论年龄、性别、临床分期和组织学分类，P53基因外显子5-8以及K-ras和N-ras基因外显子1-2均未检测到突变。我们的数据表明，P53和ras突变与神经母细胞瘤的病因无关，但其他基因可能在该肿瘤中起主要作用。注：由于DNA的严重断裂，分析MDM2基因扩增是如此困难，以至于我们无法完成这项工作。

The p53 gene frequently is affected by point mutations or deletions that contribute to the onset and progression of a wide variety of human adult solid tumors. Neuroblastoma is a common childhood malignancy of the sympathetic nervous system. However, to our knowledge, this gene alteration has been little analyzed in neuroblastoma.In this project, we prepared genomic DNA samples which were extracted from paraffin embedded blocks of 36 primary neuroblastomas. We screened for the presence of mutations in exons 5-8 of the p53 gene where over 90% of mutations have been reported to be located in human cancer. We also examined mutations of the K-ras and N-ras gene which are involved in a number of neoplasms. The screening technique employed polymerase chain reaction / single-strand conformation polymorphism analysis (PCR-SSCP) and potential mutations were further confirmed by a sequence analysis.In consequence, no mutations were detected within the exon 5-8 of the p53 gene and exon 1-2 of the K-ras and N-ras gene, regardless of the age, sex clinical staging and histological classification. Our data suggests that p53 and ras mutations do not contribute to the etiology of neuroblastomas, but other genes presumably play a major role in this tumor.Note ; Analysis of MDM2 gene amplification was so difficult due to severe fragmentation of DNA that we could not accomplish it.