New strategies in glioblastoma: exploiting the new biology

Glioblastoma is one of the deadliest human cancers. There have been few significant therapeutic advances in the field over the past two decades, with median survival of only about 15 months despite aggressive neurosurgery, radiotherapy, and chemotherapy. Nevertheless, the past 5 years has seen an explosion in our understanding of the genetic and molecular underpinnings of these tumors, leading to renewed optimism about potential new therapeutic approaches. Several of the most promising new approaches include oncogenic signal transduction inhibition, angiogenesis inhibition, targeting canonical stem cell pathways in glioblastoma stem cells, and immunotherapy. As promising as many of these approaches appear, they have not had an impact yet on the natural history of the disease or on patient long-term outcomes. Nevertheless, it is hoped that with time such approaches will lead to more effective treatments, but issues such as the unique biology and anatomy of the central nervous system, impaired drug delivery, poor preclinical models with resultant nonpredictive preclinical screening, and poor clinical trial design potentially impede the rapid development of such new therapies. In this article, we review the excitement and challenges that face the development of effective new treatments that exploit this new biology.