In line with these reports, we observed a reduced activating phosphorylation status of SRC, AKT, and ERK1/2 in both human and canine osteosarcoma cells upon silencing of the EphA2 receptor expression (Figure 7); however, mTOR phosphorylation was affected only in canine OS cells, possibly reflecting some cell line variations. This evidence concerns the gene MAPK3 and osteosarcoma.