The role of angiogenesis in tumor development and anti-angiogenesis research are important avenues for future studies of brain tumor therapy. Modalities for drug delivery through the BBB entail disruption of the BBB, either by osmotic means or biochemically by the use of vasoactive substances such as bradykinin. The potential for using BBB opening to target specific agents to brain tumors has just begun to be explored. Strategies for drug delivery behind the BBB include intracerebral implantation and convection-enhanced distribution. There is a need to determine which strategies are most effective and how they can be improved for patients with brain tumors.
Cerebral edema is a serious complication in many patients with brain tumors.
The molecular and gene-related mechanisms underlying the formation of cerebral edema need to be identified. Also needed are more quantitative methods to measure flux or transfer rate constants as indicators of vascular permeability in patients and experimental animals. We also need to improve our understanding of how to reverse edema and to better understand the mechanisms underlying the effects of current therapies. Current in vitro models of the BBB are inadequate. Basic research on brain tumors would be facilitated by the development of appropriate models that simulate the human condition in situ.