Value of correlative biomarkers in understanding tumor biology

We appreciate the insightful review of our article Batchelor et al. “Improved tumor oxygenation and survival in glioblastoma patients who show increased blood perfusion after cediranib and chemoradiation” by Dr. Burt Nabors (1,2). In his commentary, he skillfully highlights the initial enthusiasm followed by more measured interest for anti-angiogenic agents in glioblastoma (GBM) (1). Based on the robust angiogenesis that characterizes GBM, there exists a strong biological rationale for targeting tumor blood vessels and, fundamentally, blood flow and nutrient delivery are essential to tumor survival. The therapeutic challenge with this class of agents has been identifying those patients likely to benefit and achieve a durable response both clinically and radiographically.