CDKN1B and neoplasm: Most notably BKM120, was observed to: 1) induce p21waf1, p27kip1 and p53 expression 2) suppress proliferation and the expression of proliferative markers, cyclin D, MycN, gli-1, gli-2 3) induce apoptosis in the CD15+ TPC compartment and in the SHH subgroup of patient derived tumor cells (PDX) and 4) suppress tumorigenesis and increase host survival in an in vivo CD15+ TPC xenograft model.