This means that organoids contain for instance urothelial cells expressing cytokeratins (CK) [57,59], mesenchymal cells expressing vimentin, endothelial cells or smooth muscle cells expressing phalloidin [57], BC progenitor cells expressing BC stem cell markers such CD24, CD44 [86,87], Ki67pos proliferation competent cells [59], and others. Here, CD44 is linked to breast cancer.