MTOR and sarcoma: For example, Ras is capable of activating the PI3K/AKT/mTOR pathway in addition to the Raf/MEK/ERK pathway, whereas ERK can activate mTOR signaling.24 Interestingly, the AKT/mTOR and MEK/ERK pathways are known to be activated in some sarcoma subtypes.34, 35, 36 However, the mechanism underlying signal transduction between MEK, ERK and mTOR signaling in chondrosarcoma remains unclear.