In neuroblastomas, aberrantly methylated genes, 64% for THBS1; 30% for TIMP-3; 27% for MGMT; 25% for p73; 18% for RB1; 14% for DAPK, p14ARF, p16INK4a and CASP8, respectively, and 0% for TP53 and GSTP1 have been reported and the striking differences in methylation status within neuroblastomas has suggested the existence of methylator phenotype, which might be associated with more aggressive forms of neuroblastoma (22,23). This evidence concerns the gene RB1 and neuroblastoma.