Biomimetic Scaffold-Based 3D Models for Decoding Cancer Biology and Advancing Therapy.

While conventional two-dimensional (2D) cultures and animal models remain essential tools, they frequently fail to recapitulate the three-dimensional (3D) architecture, biomechanical cues, and spatial complexity of human tumors, thereby limiting their translational relevance. To address these limitations, scaffold-based 3D culture systems have emerged as powerful platforms that leverage engineered biomaterials to mimic key physical and biochemical properties of the native tumor microenvironment (TME). This review systematically examines the latest advances in biomimetic scaffold-based 3D tumor models. We first outline the principal biomaterials used in scaffold fabrication, including natural and synthetic polymers, hybrid composites, and decellularized extracellular matrix (dECM). We then discuss scaffold design strategies to replicate key hallmarks of cancer, including matrix stiffness, hypoxia, metabolic gradients, viscoelasticity, cell adhesion, proteolytic remodeling, and multicellular crosstalk. Furthermore, we highlight the application of these models in drug screening, personalized medicine, radiotherapy testing, and the study of metastasis and recurrence. Finally, we address persistent challenges in standardization, scalability, and clinical translation, while offering perspectives on future directions, including 4D bioprinting, smart responsive materials, multi-omics integration, and the development of "clinical trial in a dish" platforms.