PROM1 and hepatocellular carcinoma: Although CD133 expression has been detected in both differentiated and undifferentiated cells, CD133+ hepatocellular carcinoma cells exhibit stem-like properties in both in vitro and in vivo experiments, such as generating a xenograft that histologically resembles the parent tumor, the ability to self-renew, the capability to generate daughter cells that possess some proliferative capacity [2]–[6].