Phosphatidylinositol-3-kinase(PI3K),AKT,TSC1/2,and the mammalian target of rapamycin(mTOR) signaling cascade involves many cellular processes including apoptosis,growth,proliferation and differentiation,This pathway has been found to be the most variable one in human tumors.As tumor is a poorly differentiated disease,this review examines the role of the PI3K-AKT signal pathway in cell differentiation and tumor development.