Progress in treating diffuse gliomas remains limited and is principally concerned with the confirmation that cystostatics as nitrosureum derivatives and temozolomide play a role in the treatment of these tumours. At molecular level, diffuse gliomas are a heterogeneous group of tumours. This seems to be an important explanation of why so far no important breakthrough in the treatment of these tumours has been achieved. It is thought that abnormal activation of various molecular signal systems working in parallel in the tumour cell are an important cause of the absence of efficacy of the targeted agents; the inhibition of only one target appears inadequate.