Investigation for oncogenes relating to chemotherapy resistance of human malignant gliomas

由于一组特殊的少突胶质细胞瘤对辅助治疗敏感，因此阐明这些肿瘤的生物学特性是很重要的。原位杂交分析表明，Olig基因在少突胶质系细胞中表达，在少突胶质瘤中高表达。为了阐明OLIG是否是少突胶质瘤的肿瘤特异性标志物，我们用半定量RT-PCR方法研究了OLIG转录本和OLIG2蛋白在多种神经胶质瘤中的表达。半定量RT-PCR结果显示，在间变性少突胶质细胞瘤和间变性星形细胞瘤中，寡核苷酸和寡核苷酸的表达水平较高，而在IV级胶质母细胞瘤中的表达低于II级和III级(p&lt；0.01)。免疫组织化学分析显示，间变性少突胶质细胞瘤中OLIG2的平均免疫阳性率为82%，而间变性星形细胞瘤中OLIG2的平均阳性率仅为34%。因此，尽管OLIG2在一系列胶质瘤中表达，但在间变性少突胶质瘤中的表达水平比其他胶质瘤更均匀和强烈。总之，结合Olig mRNA表达和OLIG2的免疫组织化学，可以将少突胶质瘤与胶质母细胞瘤和其他星形细胞胶质瘤区分开来。

Because a specific group of oligodendrogliomas is susceptible to adjuvant therapy, it is important to elucidate the biological characteristics of these tumors. In situ hybridization analyses have revealed that Olig genes are expressed in oligodendroglial lineage cells and are highly expressed in oligodendrogliomas. To clarify whether OLIG is a tumor-specific marker for oligodendrogliomas, we have investigated the expression of Olig transcripts by semiquantitative RT-PCR assay and OLIG2 protein with a new antibody in a variety of glial tumors. The semiquantitative RT-PCR revealed that high levels of expression of Olig1 and Olig2 mRNAs were present in anaplastic oligodendrogliomas and anaplastic astrocytomas, while expression of these mRNAs in grade IV glioblastomas was lower than in grade II and grade III gliomas (p<0.01). Immunohistochemical analyses demonstrated that the mean immunopositive proportion of OLIG2 was 82% in anaplastic oligodendrogliomas, but only 34% in anaplastic astrocytomas. Therefore, although OLIG2 expression was detected in a range of gliomas not specific for oligodendrogliomas, the expression level in anaplastic oligodendrogliomas was more uniform and intense than that in other glial tumors. In conclusion, combining Olig mRNA expression and immunohistochemistry of OLIG2 enables oligodendrogliomas to be distinguished from glioblastomas and other astrocytic glial tumors.