摘要
目的研究不同分化程度的神经母细胞瘤(NB)中 E-cadherin、β—catenin 蛋白的表达情况,初步探讨 E-cadherin、β—catenin 异常表达的分子生物学机制及其与临床病理参数的关系。方法免疫组织化学 EnVision 法检测黏附分子 E-cadherin、β—catenin 在90例石蜡包埋组织中的表达;对7例NB 的新鲜样本和24例 NB 石蜡包埋组织采用甲基化特异性 PCR(MSP)方法检测 E-cadherin 基因启动子 CpG 岛甲基化状态;运用 PCR 扩增和测序方法,检测7例 NB 组织中β—catenin 基因第3外显子的突变情况,采用 SPSS 统计分析软件进行相关性分析。结果分化良好组织类型 NB β—catenin 的阳性表达率(47/70,67.1%)显著高于分化不良组织类型(8/20,40.0%);E-cadherin、β—catenin 在 NB 中普遍呈异常表达;有淋巴结转移组中 E-cadherin 和β—catenin 的阳性表达率较无淋巴结转移组显著下降;检测31例 NB E-cadherin 基因启动子的部分区域均为未甲基化状态;对β—catenin 第3外显子 PCR扩增产物进行 DNA 测序,7例 NB 中1例发生基因重排和点突变,2例发生点突变,其中2例在同一位点(27184)发生 T→A的突变。结论 NB 中黏附分子 E-cadherin 高异常表达率与实验中检测的启动子区域甲基化无关,是否与该启动子未检测区域 CpG 岛甲基化有关,还需进一步实验证实;β-catenin的高异常表达率可能与β—catenin 基因第3外显子的突变有关。
Objective To study the expression of E-cadherin and β-catenin in neuroblastomas of various degrees of differentiation, and to investigate their molecular mechanisms in correlation with clinicopathologic parameters. Methods Immunohistochemistry EnVision method was used to detect E-cadherin and β-catenin expression in 90 paraffin-embedded tissue samples of neuroblastomas. The methylation status of CpG islands of E-cadherin promoter was investigated by MSP in 7 fresh tissue and 24 paraffin-embedded tissue samples. The mutation status of exon 3 of β-catenin gene was studied by PCR in 7 fresh tissue samples. Statistical analysis of the data was performed by SPSS software. Results E-cadherin and β-catenin were abnormally expressed in neuroblastomas in general. The expression of β-catenin in well- differentiated neuroblastoms was markedly higher （47/70,67. 1% ） than that of the poorly differentiated tumors（8/20,40. 0% ）. There was a markedly decreased expression of both genes in tumors with lymph node metastasis than those without. Demethylatlon was seen in some regions of the promoter of E-cadherin in 31 cases of nuroblatomas. PCR of the exon 3 of β-catenin followed by DNA sequencing demonstrated rearrangements and mutations in 7 cases, including 2 cases harboring identical point mutation at gene position 27184, leading to a T→A alteration. Conclusions The abnormal over-expression of E-cadherin in neuroblastomas is independent of the methylation status of their promoter sequences. The abnormal expression of β-catenin may be related to mutational changes at exon 3 of the gene.
出处
《中华病理学杂志》
CAS
CSCD
北大核心
2007年第3期155-159,共5页
Chinese Journal of Pathology
