The most common known molecular defect in Wilms tumor (WT) of the kidney, the most frequent solid tumor of childhood, is loss of imprinting (LOI) of the insulin-like growth factor-II gene (IGF2), which involves activation of the normally silent maternal allele of the gene and hypermethylation of a differentially methylated region upstream of the H19 gene.
The H19 gene, which localizes within a chromosomal region on human chromosome 11p15 that is commonly lost in Wilms tumor (WT), encodes an imprinted untranslated RNA.
This contrasts the situation we found at the IGF2/H19 locus, which shows high overexpression of IGF2 and inversely correlated expression of the H19 gene in WT.