The development of rapid diagnostic system for detecting a predisposition to cancer in early childhood

检测了急性淋巴细胞白血病（ALL）和儿童实体瘤中p16和p15基因纯合性缺失（HD）以及p16、RAS和p53基因突变。p16基因重排在无t（1 ; 19）的白血病细胞系和新鲜白血病中的表达高于有t（1; 19）的白血病细胞系和新鲜白血病。值得注意的是，在3例原发病例中发现了突变（5%）。在伴有MLL重排的白血病（MLL+）中，19例AML中有5例（11%）p16和p15基因存在HD。PCR-单链构象多态性分析（SSCP）结果显示32例患者均未发现突变。结果表明，在57例T-ALL患者中，有3例（5%）、14例复发患者中有1例（7%）和18个细胞系中有12例（67%）存在p53基因突变，所有p53突变患者均在病程中死亡。在71个新鲜样本和18个细胞系中未发现p21基因突变。N-RAS突变 关于我们 在57例T-ALL患者中有2例（4%）在诊断时才发现，在118个细胞系中有4个（22%）。p16基因的改变被发现在18的47（38%）患者在诊断和7的14（50%）在复发（不显着）。无事件患者和其余患者之间p16和p15基因改变的频率没有差异。在7例无纯合性缺失的T-ALL患者中，有3例p16基因甲基化，提示T-ALL中p16基因失活的发生率高于以往报道。81例未发现p16类型的HD。PCR-SSCP分析仅发现错义突变，提示多态性。10个细胞系中有6个细胞p16基因表达缺失或降低。在19个细胞系中，有12个细胞系存在p16基因的高甲基化，提示高甲基化在神经母细胞瘤的发生发展中起重要作用。DCC基因表达缺失或减少的样本中发现有一半。PCR-SSCP分析显示DCC基因仅有错义突变，提示存在多态性。DPC 4和MDRR 2基因的改变相对罕见。提示DCC基因在NB的传播中起重要作用，DPC 4和MAD 2基因与NB的发生无关。本研究为建立儿童早期肿瘤易感性的快速诊断系统提供了依据。少

Homozygous deletions (HD) of p16 and p15 genes and mutations of pl6, RAS and p53 genes were examined in acute lymphoblastic leukemia (ALL) and childhood solid tumors. Rearrangements of p16 were higher in cell lines and fresh leukemia without t(1 ; 19) than those with t(l ; 19). Remarkably, mutations were found in 3 of the primary cases (5%). As for leukemia with MLL rearrangement (MLL+), HD of the p16 and p15 genes was found in 5 (11%) of 19 acute myeloid leukemias (AMLs). PCR-single strand conformation polymorphism (SSCP) showed no mutation in the 32 patients tested. Our results suggest that alterations of 16 and p15 genes are involved in a subset of acute leukemias with MLL.Mutations of the p53 gene were found in 3 of 57 (5%) T-ALL patients at diagnosis, 1 of 14 (7%) patients at relapse and in 12 of 18 (67%) cell lines, All patients with p53 mutations in the course of disease died. Mutations of the p21 gene were not identified in 71 fresh samples and in 18 cell lines. N-RAS mutations … More were found in 2 of 57 (4%) fresh T-ALL patients only at diagnosis, and 4 of 118 cell lines (22%). Alterations of the p16 gene were found in 18 of 47(38%) patients at diagnosis and in 7 of 14(50%) at relapse (not significant). There were no differences in the frequency of alteration of the p16 and p15 genes between event-free patients and the remaining patients. Furthermore, we found the methylation of p16 gene in 3 of 7 patients lacking homozygous deletions, suggesting higher frequency of p16 inactivation than previous reports in T-ALL.N-myc, p16, DCC, DPC4, MADR2 and p73 genes were analyzed in neuroblastoma (NB). HD of p16 genre was not found in 81 samples. PCR-SSCP analysis identified only missense mutation, suggesting polymorphism. Absence or decreased expression of pl6 gene was found in 6 of 10 cell lines. Hypermethylation of the p16 gene was found in 12 of 19 cell lines, suggesting that hypermethylation plays an important role for the development or progression of neuroblastoma. Absence or reduced expression of DCC gene was found in half of the samples. PCR-SSCP analysis of DCC gene showed only missense mutation, suggesting polymorphism. Alterations of DPC4 and MDRR2 genes were relatively rare. These results suggest that DCC gene plays an important role in the dissemination of NB, and that DPC4 and MAD2 gene are not involved in the development of NB.This study may counribute to the development of rapid diagnostic system for detecting a predisposition to cancer in early childhood. Less