While in several solid tumors [26], CD133hi cells are heralded as the cells with CSC properties, there are also contrasting reports of CD133lo subset being capable of exhibiting tumorigenicity and clone forming ability in tumors such as Glioma [27], Glioblastoma [28], Colon cancer [29], etc. Sun and co-workers reported that in neural stem cells, the CD133 negative population are clonogenic and slow cycling in nature [30]. This evidence concerns the gene PROM1 and central nervous system cancer.