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

对急性淋巴细胞白血病(ALL)和儿童实体瘤进行了p16、p15基因纯合缺失(HD)和p16、ras、p53基因突变检测。P16基因重排在无t(1；19)的白血病细胞系和新鲜白血病高于有t(L；19)的白血病细胞系。值得注意的是，在3例原发病例中发现了突变(5%)。在伴有MLL重排的白血病中，19例急性髓系白血病(AML)中有5例(11%)存在p16和p15基因缺失。聚合酶链式反应-单链构象多态(SSCP)检测32例患者均未发现突变。我们的结果表明，16和p15基因的改变与急性白血病的一个亚群有关，在57例初诊T-ALL患者中有3例(5%)发生了p53基因突变，在14例复发患者中发现了1例(7%)，在18个细胞系中发现了12例(67%)，所有病程中有p53突变的患者都死亡了。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…在57例新鲜T-ALL患者中有2例(4%)在确诊时发现了更多的T-ALL，在118个细胞系中发现了更多的T-ALL(22%)。在47例初诊患者中有18例(38%)出现p16基因改变，在14例复发患者中有7例(50%)出现p16基因改变(无显著意义)。在无事件患者和其余患者之间，p16和p15基因的改变频率没有差异。此外，我们还发现在7例缺失纯合子缺失的患者中有3例存在p16基因甲基化，提示在神经母细胞瘤中分析的T-ALLegy-myc、p16、DCC、DPC4、MADR2和p73基因中p16失活的频率比以往报道的高。81例标本中未发现p16亚型HD。PCR-SSCP分析仅检测到错义突变，提示存在多态。在10个细胞株中，有6个细胞株的pl6基因表达缺失或降低。在19个细胞系中有12个发现p16基因高甲基化，提示高甲基化在神经母细胞瘤的发生发展中起重要作用。半数标本中DCC基因表达缺失或降低。DCC基因的PCR-SSCP分析仅显示错义突变，提示存在多态现象。DPC4和MDRR2基因的改变相对较少。这些结果提示DCC基因在NB的传播中起重要作用，而DPC4和MAD2基因不参与NBB的发生发展。本研究可能有助于建立儿童早期癌症易感性的快速诊断系统。较少

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