MTOR and neoplasm: Mechanistically, the PI3K-AKT-mammalian target of the rapamycin (mTOR) pathway, a key driver of tumor progression, was shown to play a causal role in prostate tumorigenesis through the up-regulation of pyruvate kinase isoenzyme type M2 (PKM2), the rate-limiting enzyme catalyzing the final reaction of the glycolytic pathway [151,152].