TSC1 and cancer: In many cancers, mTORC1 is observed to be upregulated, and this is often a consequence of mutations or hyperactivation of upstream regulators Akt, PI3K and RAS or suppression of inhibitory regulators such as liver kinase B1 (LKB1), the phosphatase tensin homolog deleted on chromosome 10 (PTEN) and tuberous sclerosis proteins 1 and 2 (TSC1/2).