NCAM1 and neoplasm: We performed immunostaining of p-WT Xn and parental WT for the following: WT1, a specific clinical diagnostic marker for WT; NCAM1, a putative marker for a tumour progenitor population previously shown in in vitro assays of primary cell cultures of WT (Pode-Shakked et al, 2009); and Ki-67, a cell proliferation marker.