AKT1 and primary central nervous system lymphoma: Recent studies using immunohistochemistry, western blotting, and real-time qPCR have shown significantly higher expression levels of components in the PI3K-Akt-mTOR pathway in PCNSL patients, such as p-AKT, p-mTOR, p-S6 and p-4E-BP1 and mTOR, and this aberrant activation is correlated with poor prognosis (35).