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

在急性淋巴细胞白血病（ALL）和儿童实体瘤中检测p16和p15基因的纯合缺失（HD）和pl6、RAS和p53基因的突变。p16的重排在没有t（1; 19）的细胞系和新鲜白血病中高于有t（1; 19）的细胞系和新鲜白血病。值得注意的是，在3例原发性病例中发现了突变（5%）。在MLL重排白血病（MLL+）中，19例急性髓系白血病（AMLs）中有5例（11%）出现p16和p15基因HD。pcr -单链构象多态性（SSCP）在32例患者中未发现突变。我们的研究结果表明，16和p15基因的改变与急性白血病伴MLL的一个亚群有关。57例T-ALL患者诊断时发现3例（5%）p53基因突变，14例复发时发现1例（7%）p53基因突变，18例细胞系中发现12例（67%）p53基因突变，所有病程中p53基因突变的患者死亡。在71个新鲜样品和18个细胞系中未发现p21基因突变。N-RAS突变…57例新T-ALL患者中有2例（4%）在诊断时发现更多，118个细胞系中有4例（22%）发现更多。47例患者中有18例（38%）在诊断时发现p16基因改变，14例患者中有7例（50%）在复发时发现p16基因改变（无统计学意义）。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，我们在7例缺乏纯合缺失的患者中发现3例p16基因甲基化，这表明p16失活的频率高于之前报道的T-ALL。N-myc、p16、DCC、DPC4、MADR2和p73基因在神经母细胞瘤（NB）中的表达。81份样本未发现p16类型HD。PCR-SSCP分析仅发现错义突变，提示多态性。10株细胞系中有6株pl6基因缺失或表达降低。19个细胞系中有12个发现p16基因的高甲基化，提示高甲基化在神经母细胞瘤的发生或进展中起重要作用。半数样本中发现DCC基因缺失或表达降低。PCR-SSCP分析显示DCC基因仅有错义突变，提示多态性。DPC4和mdr2基因的改变相对罕见。这些结果表明，DCC基因在NB的传播中起重要作用，而DPC4和MAD2基因在NB的发生发展中没有参与。本研究可能有助于快速诊断系统的发展，以检测早期儿童的癌症易感性。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