Although it has long been assumed that neoplastic formation derives from alterations within adult colonic stem cells, the existence of colorectal cancer stem cells (CR-CSCs) has been demonstrated through the finding that colon CD133+ cells are able to grow exponentially in vitro as undifferentiated tumor spheres, when cultivated in serum-free medium, and initiate tumor growth in mouse models, thus reproducing the same morphological and antigenic pattern of the original human tumor [21-23]. Here, PROM1 is linked to neoplasm.