MTOR and hemangioma: The pathways implicated in hemangioma tumorigenesis are the MAP kinase pathway MEK/ERK cascade, PI3 kinase pathway (phosphatidylinostitol-3 kinase (PI3K)/serine-threonine protein kinase/Akt/mTOR/p70S6K cascade), and the phospholipase second messenger system (phospholipase C-γ/intracellular Ca2+/(protein kinase C (PKC) cascade).