PTEN and neoplasm: Increased activation of mTORC1 is observed in several human neoplasia due to gain-of- function mutations in different oncogenes, including PI3 kinase, AKT or ras, and/or loss-of-function mutations in a variety of tumour suppressor genes, such as PTEN, LKB1 or TSC1/2, among the upstream regulators of mTORC1.