PROM1 and neoplasm: We found in vivo segregation of the CD133-expressing (CD133hi) cell population (17.55 ± 2.50% of all tumor cells) and the population of cells with active Notch signaling (Notchhi; 3.87 ± 0.85% of all tumor cells, n = 4 mice implanted with NotchLenti-transduced GBML8 cells) (Figure 2ai).