Glioblastoma as a dynamic tumor ecosystem: from molecular alterations to therapeutic translation

For more than a century after its initial description, glioblastoma (GBM) has remained one of the most therapeutically refractory human malignancies, resembling an almost impregnable fortress against modern oncology. Despite extensive molecular characterization and identification of numerous actionable targets, survival outcomes have improved only marginally. GBM is characterized by profound spatial and cellular heterogeneity, adaptive signaling rewiring, extensive phenotypic plasticity, an immunosuppressive tumor microenvironment, and major pharmacological constraints imposed by the blood-brain barrier. This review examines the resulting disconnect between biological rationale and clinical outcome through three interrelated translational principles that determine whether mechanistically compelling therapies can achieve meaningful clinical benefit in GBM. First, who is treated and what is biologically active: therapeutic efficacy depends on matching patients to functional pathway dependencies beyond static molecular alterations. Second, whether the drug reaches and modulates its intended target: candidate therapies must achieve sufficient intratumoral exposure and demonstrate target modulation. Third, how the tumor adapts under therapeutic pressure: durable efficacy requires accounting for receptor tyrosine kinase switching, phenotypic plasticity, immune adaptation, and spatial escape. By linking these principles to the molecular, spatial, and pharmacological organization of GBM, this review frames the disease as a dynamic tumor ecosystem and provides a framework for interpreting recurrent clinical failure and guiding more biologically informed therapeutic development.