8 Conclusions

The treatment of brain cancer is one of the most difficult challenges in neurosurgeryand oncology. Malignant gliomas involve, in their progression, multiple aberrant signaling pathways and the BBB restricts the delivery of many chemotherapeutic agents. Targeted therapies have successfully been applied in cancers, but their efficacy remains low in malignant brain tumors [266]. There are several factors underlying the disappointing results in brain cancer therapeutics including limited tumor cell drug uptake, intracellular drug metabolism, inherent tumor sensitivity to chemotherapy, and cellular mechanisms of resistance. The results in the first experimental studies suggest that a single antiangiogenic therapy is not sufficient to eradicate glioma [31, 245].