MTOR and angiosarcoma: Although the effect of the aberrant PI3K-AKT-mTOR signaling on tumor cell proliferation and apoptosis is well-known in canine OSA, the relation between mTOR and migration, invasion, and angiogenesis properties has been better explored in other types of canine cancer including hemangiosarcoma (194), prostate cancer (195), mammary tumors (196, 197), melanoma (198), and mast cell tumors (199).