PROM1 and central nervous system cancer: CD133 is a membrane protein interconnected with the Phosphoinositide 3-kinase Class I (PI3K)/Thymoma viral oncogene protein kinase (Akt) pathway; phosphorylation of tyrosine-828 within its C-terminal cytoplasmic domain mediates direct interaction with the PI3K 85 kDa regulatory subunit (p85) and favours the preferential activation of the Akt pathway in glioma stem cells relative to matched non-stem cells [24].