ROR1 and osteosarcoma: The targets reported so far for ATC in osteosarcoma include HER2, GD2, B7-H3 (CD276), interleukin-11 receptor α-chain (IL-11Rα), insulin-like growth factor 1 receptor (IGF1R), receptor tyrosine kinase-like orphan receptor 1 (ROR1), erythropoietin-producing hepatocellular class A2 (EphA2), natural killer group 2D ligand (NKG2DL), activated leukocyte cell adhesion molecule (ALCAM, CD166), folate receptor-α (FRα), chondroitin sulfate proteoglycan 4 (CSPG4), and CD151 [59,60,61].