Recent advances in biological research on malignant glioma and their therapeutic relevance

Despite recent advances in various therapeutic modalities for treating malignant gliomas, these tumors are still hardly curable, and the development of the new therapies is warranted in the field of chemotherapy and radiotherapy. In this context, many therapeutic compounds have been investigated, and, especially, drug treatment using molecular targeting compounds has attracted considerable attention amongst neuro-oncologists. Since previous studies have elucidated that malignant gliomas show an up-regulation of various growth factor receptor-related activities, many clinical studies using compounds targeting those receptors have been conducted. However, the development of effective molecular targeting therapy for malignant gliomas is limited by a relative lack of understanding of the biology of glioma cells. Thus, laboratory investigation including an animal tumor model is indispensible in designing a better therapeutic approach for these tumors. On the other hand, genetic analysis of gliomas has led to the discovery of prognostic markers. Recent clinical studies focusing on genetic markers has revealed the importance of the methylation status of the O⁶-methylguanine-DNA methyltransferase promoter and mutational status of isocitrate dehydrogenase 1 as prognostic factors of gliomas, leading to the idea that genetic analysis could help in selecting cases with a favorable treatment response and, possibly, individualization of the treatment. In this text, recent advances in glioma biology are reviewed to help better understand the problems and future prospects in the treatment of these tumors.