Tumor Spheroids, Tumor Organoids, Tumor Explants, and Tumoroids: What Are the Differences between Them?

Three-dimensional (3D) cell cultures that mimic tumor microenvironment have become an essential tool in cancer research and drug response analysis, significantly enhancing our understanding of tumor biology and advancing personalized medicine. Currently, the most widely mentioned 3D multicellular culture models include spheroids, organoids, tumor explants, and tumoroids. These 3D structures, exploited for various applications, are generated from cancer and non-cancer cells of different origin using multiple techniques. However, despite extensive research and numerous studies, consistent definitions of these 3D culture models are not clearly established. The manuscript provides a comprehensive overview of these models, detailing brief history of their research, unique biological characteristics, advantages, limitations, and specific applications.