Biomaterial based spheroid and organoid modeling. (A) Approaches to develop 3D tumor models from immortalized cell lines as spheroids and biopsies as organoids. Various natural and synthetic materials offer unique advantages to facilitate self-assembly or directed assembly of cells into these models. (B) Representative images of spheroids and organoids formed using cells of different cancers. Images in (B) were reproduced with permission. [74] Copyright 2010, Elsevier. [92] Copyright 2014, Elsevier. [101] Copyright 2016, John Wiley and Sons, [163] Copyright 2015, Nature Publishing Group. [165] Copyright 2017, Nature Publishing Group. [158] Copyright 2014, Elsevier. [157] Copyright 2014, Nature Publishing Group.