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Spheroids and organoids are both 3D structures made of many cells. Although this terminology has been interchangeably used there are distinct differences between them. An organoid is a “collection of organ-specific cell types that develops from stem cells or organ progenitors and self-organizes through cell sorting and spatially restricted lineage commitment in a manner similar to in vivo” (Science 2014. 345:124). On the other hand, multicellular tumor spheroid model was first described in the early 70s and obtained by culture of cancer cell lines under non-adherent conditions (J. Natl. Cancer Inst. 1971. 46:113). Tumorospheres, is a model of cancer stem cell expansion; tissue-derived tumor spheres and organotypic multicellular spheroids are typically obtained by tumor tissue mechanical dissociation and cutting (Neoplasia (2015) 17, 1–15). Generally, there is a higher order self-assembly in organoids as opposed to spheroid cultures and the former is more dependent on a matrix for its generation.
Organoids have recently become of great interest as a model, primarily as may serve as a better in vitro model as compared to 2D or even 3D co-culture systems. Common areas of interest for organoid research include organ development, drug screening, disease modeling, and toxicity testing. The hope is that organoids will bring researchers one step closer to in vitro models. Here are some reviews that discuss recent organoid publications: