Previously, mutations such as single amino acid changes which were clustered in the kinase active sites by genetic approaches using yeast conferred the constitutive hyperactivation of mTOR and somatic aberrations of PTEN/AKT/mTOR axis genes had been generally observed in various cancers including PCa [35], [36], [37], [38], [39]. The gene discussed is PTEN; the disease is posterior cortical atrophy.