Both fractions of Wilms' tumor (NCAM1+ADLH1+ and NCAM1+ADLH1−) showed a strong overexpression of the mesenchymal isoform, and all fractions of the fetal cells grown in SFM (NCAM+CD133−, NCAM+CD133+, and NCAM−CD133+) expressed the epithelial isoform. The gene discussed is PROM1; the disease is Wilms tumor.