HIF1A and glioblastoma: We investigated the expression levels of hypoxic markers (CA9 and HIF-1α) and a GSC marker (nestin) using GBM samples obtained from three different settings including tumors before Bev therapy (naive-Bev), tumors resected following neoBev (effective-Bev), and recurrent tumors following Bev therapy (refractory-Bev) (3).