Upstream regulation of the second mTOR complex, mTORC2, is less well understood, although it may be activated by PI3K signalling and ribosome binding.108 mTORC2 is most commonly known for its ability to phosphorylate and activate AKT,109 resulting in overlapping positive feedback loops within the PI3K pathway that can be a major oncogenic driver and mechanism of resistance to PI3K/AKT/mTOR inhibition in glioblastoma. Here, PIK3CA is linked to glioblastoma.