The three Wilms’ tumor xenografts (WT11, WT14, and WT37) are closer to hFK1, the most immature fetal cell fraction, than to the other two fetal cell fractions (hFK2 and hFK3), which indicates that these Wilms’ tumors resemble an early stage in fetal kidney development. This evidence concerns the gene FOXG1 and Nephroblastoma.