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中的一个分泌型成员，在人的肺和结肠中扩增频率很高。在本研究中，我采用半定量基因组聚合酶链式反应检测了57例人脑星形细胞肿瘤中DcR3基因的扩增，其中包括34例胶质母细胞瘤，并用实时定量逆转录-聚合酶链式反应检测了24例星形细胞脑肿瘤中DcR3基因的表达，其中包括13例胶质母细胞瘤。低级别星形细胞瘤7例(0%)、间变性星形细胞瘤1例(5.9%)、胶质母细胞瘤7例(20.6%)均未检测到DcR3基因扩增。DcR3mRNA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表达呈正相关。DcR3在人脑星形细胞肿瘤中的表达与基因扩增有关。在大量胶质母细胞瘤中观察到Fas免疫反应阳性。这些结果提示，DcR3的高表达和基因扩增可能与高级别星形细胞肿瘤的恶性特征有关，可能与逃避FasL-Fas介导的细胞死亡有关。

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.