Necrogenesis in human astrocytic tumors especially based on decoy receptor 3 gene amplification and expression

诱骗受体3（DcR3）是肿瘤坏死因子受体超家族的分泌型成员，在人肺和结肠中以高频率扩增。在这项研究中，我检查了57人星形细胞脑肿瘤，包括34个胶质母细胞瘤和实时半定量逆转录-PCR DcR3 mRNA表达的半定量基因组PCR扩增DcR3基因在24个星形细胞脑肿瘤，包括13个胶质母细胞瘤。7例低级别星形细胞瘤中无一例（0%）DcR3基因扩增，17例间变性星形细胞瘤中1例（5.9%），34例胶质母细胞瘤中7例（20.6%）。DcR3 mRNA在胶质母细胞瘤中的表达高于低级别星形细胞瘤。24例星形细胞肿瘤中DcR3基因扩增与mRNA表达呈显著正相关。DcR3 mRNA在人脑星形细胞肿瘤中的表达依赖于基因扩增。在大量的胶质母细胞瘤病例中观察到Fas免疫反应性。这些结果表明，DcR3高表达和基因扩增可能是导致高级别星形细胞肿瘤恶性特征的原因，这可能归因于逃避FasL-Fas介导的细胞死亡。

Decoy receptor 3 (DcR3), a secreted member of the tumor necrosis factor receptor superfamily, is amplified at high frequency in human lung and colon. In this study, I examined the DcR3 gene amplification by semi-quantitative genomic PCR in 57 human astrocytic brain tumors, including 34 glioblastomas and DcR3 mRNA expression by real-time semi-quantitative reverse transcription-PCR in 24 astrocytic brain tumors, including 13 glioblastomas. DcR3 gene amplification was detected in none of 7 (0%) low-grade astrocytomas, 1 of 17 (5.9%) anaplastic astrocytomas, and 7 of 34 (20.6%) glioblastomas. DcR3 mRNA tend to express high in glioblastomas than low grade astrocytomas. A well correlation between DcR3 gene amplification and mRNA expression was found in 24 astrocytic tumors. Expression of DcR3 mRNA in human astrocytic tumors was dependent of gene amplification. Immunoreactivity to Fas was observed in a large number of glioblastoma cases. These results suggest that high DcR3 expression with gene amplification might be responsible to malignant featuresin high grade astrocytic tumors, that may be attributed to escape from FasL-Fas mediated cell death.