MTOR and posterior cortical atrophy: Recent evidence suggest that PI3K/Akt/phosphatase and tensin homolog (PTEN)/mammalian target of rapamycin (mTOR) signaling pathway, autophagy, epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs) play important roles in PCa tumorigenesis and may collectively contribute to radioresistance [2].