Accordingly, application of EGF in an appropriate dose range (which differed between cell lines) protected osteosarcoma cells against serum starvation independent of the endogenous EGFR expression level (examples for cell lines with high endogenous EGFR expression in Fig. 2c and Additional file 3: Figure S2A and with comparable low expression levels in Additional file 3: Figure S2B). Here, EGF is linked to osteosarcoma.