Our results also illustrate that chondroblast-like OS cells and OSCs share feedback pathways, including the VIM-CD44 and COL2A1-DDR2 pathways; these findings are also confirmed by other studies that show that the hierarchy induced by CSCs is not a one-way route but is reversible or plastic in the presence of a new hierarchical CSC clone54, adding to functional tumor diversity55,56. This evidence concerns the gene COL2A1 and neoplasm.