PROM1 and neoplasm: Previous literature suggested that CD133-expressing tumor cell populations are enriched for stem-like cells with enhanced tumorigenic potential.2, 23 CD133+ GSCs are found not only in perivascular areas but also in the hypoxic areas of PPN.10, 11, 12 Therefore, profiling gene expression in CD133+ cells can reveal molecular signatures relevant to hypoxia-driven tumor growth.