TEK and fibrosarcoma: The major signaling pathways that govern the development of these anomalies include (a) RAS (rat sarcoma)/RAF (rapidly accelerated fibrosarcoma)/MAPK (mitogen-activated protein kinase)/ERK (extracellular signal-regulated kinase); (b) angiopoietin/TIE2 (angiopoietin-1 receptor) and PI3K (phosphoinositide 3-kinase)/AKT (protein kinase B)/mTOR (mammalian target of Rapamycin); (c) TGF-β (transforming growth factor beta) signaling and (d) the G protein–coupled receptor signaling molecules (GNA [G protein subunit alpha] Q/GNA11/GNA14) [34,35].