EGFR and osteosarcoma: To explore the mechanisms by which ZD6474 inhibits the proliferation of osteosarcoma cells, EGFR expression was firstly evaluated at the protein level, and visible bands of EGFR protein was detected in all of osteosarcoma cells, and these is a high EGFR expression in MG-63 and MNNG/HOS CL#5 cells compared with that in U2OS cells (Figure 4A).