Toward functional precision oncology: organotypic brain slices in glioblastoma

Glioblastoma remains the most aggressive primary brain tumor in adults and is characterized by extensive invasiveness, high recurrence rates, and pronounced inter- and intratumoral heterogeneity. These features continue to limit the effectiveness of current therapies and highlight the need for experimental models that more faithfully capture the complexity of the disease. Conventional two-dimensional in vitro systems, while highly accessible and experimentally tractable, fail to reproduce the three-dimensional architecture, extracellular matrix organization, and dynamic tumor-microenvironment interactions that critically shape glioblastoma behavior. Although three-dimensional spheroid and organoid models partially address these limitations, they still incompletely reflect the structural and cellular complexity of native brain tissue. Organotypic brain tissue slice cultures have emerged as a powerful intermediate model that preserves native cytoarchitecture, cellular diversity, and key aspects of the tumor microenvironment. In this review, we provide an integrated overview of organotypic slice models derived from mouse, rat, and human tissue, with a focus on their application in studying glioblastoma invasion, tumor-microenvironment interactions, and therapeutic response. We discuss methodological approaches, advances in tissue preservation and bioengineering, and the integration of molecular and electrophysiological readouts. Particular emphasis is placed on human brain slice cultures, which retain patient-specific structural and cellular features and therefore offer a unique platform for investigating tumor heterogeneity and individualized treatment responses. At the same time, we address current limitations, including restricted viability, methodological variability, and the need for standardized experimental frameworks. By positioning organotypic brain slices as structurally preserved tumor ecosystems rather than simplified experimental systems, this review highlights their potential to bridge mechanistic discovery and translational application, and to contribute to the development of functionally informed precision oncology strategies in glioblastoma.