In an evaluation of putative stem cell markers in Wilms’ tumor xenografts, CD133 and neural cell adhesion molecule (NCAM or CD56), which can be found on developing renal tubules and in kidneys recovering from ischemic injury, were felt to most likely contain the stem cell fraction, however under clonogenicity assays, only NCAM+ cells were highly clonogenic and overexpressed the Wilms tumor “stemness” genes along with the clinically bad prognostic marker, TOP2A [46,47]. Here, TOP2A is linked to Wilms tumor.