Investigation for oncogenes relating to chemotherapy resistance of human malignant gliomas

由于一类特殊的少突胶质细胞瘤易受辅助治疗的影响，阐明这些肿瘤的生物学特性是很重要的。原位杂交分析显示olig基因在少突胶质细胞谱系中表达，并在少突胶质细胞瘤中高度表达。为了明确oligg是否是少突胶质细胞瘤的肿瘤特异性标志物，我们通过半定量RT-PCR检测和一种新的抗体研究了oligg转录本在多种胶质肿瘤中的表达。半定量RT-PCR结果显示，Olig1和Olig2 mrna在间变性少突胶质细胞瘤和间变性星形细胞瘤中表达水平较高，而这些mrna在IV级胶质母细胞瘤中的表达低于II级和III级胶质瘤（p<0.01）。免疫组织化学分析显示，间变性少突胶质细胞瘤中OLIG2的平均免疫阳性比例为82%，而间变性星形细胞瘤中仅为34%。因此，尽管在非少突胶质细胞瘤特异性的胶质瘤中检测到OLIG2表达，但间变性少突胶质细胞瘤中的表达水平比其他胶质肿瘤更为均匀和强烈。综上所述，结合oligmrna的表达和OLIG2的免疫组化可以将少突胶质细胞瘤与胶质母细胞瘤和其他星形胶质细胞肿瘤区分开来。

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.