Wilms' tumor-specific methylation pattern in 11p13 detected by PFGE.

The analysis of 2,550 kb from 11p13 in Wilms' tumor (WT) material revealed two regions that differed significantly in their methylation between tumor and normal tissue. In WT a hypomethylated area defined by an NruI and MluI recognition site 100-150 kb centromeric of the WT gene WT1 (site A) and hypermethylation defined by an NruI and SacII site 100 kb telomeric of the WT1 gene were found (site B). The degree of methylation in region B varied between 20 and 100% in the different samples; the highest level was observed in tumors without preoperative chemotherapy. The CpG island 5' of the WT1 gene was partially methylated in 2/29 tumors analyzed. The methylation state of regions A and B could reflect the normal pattern present in a subset of embryonal kidney cells, from which WT develops.