MTOR and posterior cortical atrophy: Involvement of phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pro-survival signaling pathway as well as overexpression of critical cell growth and cell cycle progression factors, including c-Myc and cyclin D1, have been implicated in PCa radioresponse’s regulation [26].