The invention relates to improved culture methods for expanding epithelial stem cells and obtaining organoids, to culture media involved in said methods, and to uses of said organoids.

Three-dimensional tumor avatars comprising an artificial scaffold, tumor cells, tumor associated endothelial cells and tumor associated fibroblast cells are provided. Kits comprising the 3D tumor avatars, methods of producing the 3D tumor avatars and methods of using the 3D tumor avatars are also provided.