This is consistent with our data obtained in colorectal adenocarcinoma cell lines, where the percentage of proliferating cells measured via BrdU incorporation, the number of visualized mitoses, expression of the proliferation marker Ki67, and the ability to form colonies in vitro were higher in populations with high CD133 expression compared with cells of the same lines with low or lacking CD133 expression [68,69]. This evidence concerns the gene PROM1 and colorectal adenocarcinoma.