MTOR and cyst: Other proposed mechanisms implicated in cyst growth and expansion include dysregulated signalling pathways involving G-coupled proteins, the mammalian target of rapamycin (mTOR), phosphoinositide 3-kinase (PI3K)–protein kinase B (PKB), AMP-activated protein kinase (AMPK), Janus kinase 2 (JAK2)–signal transducer and activator of transcription (STAT), and nuclear factor of activated T cells (NFAT) [12,13,16,17,18].