Loss of heterozygosity of WT1 gene in the prognosis of sporadic Wilms' tumour in children

The aim of this report was to evaluate the prognostic value of allele loss of the WT1 gene in children with sporadic Wilms' tumour. Allele loss of the WT1 gene was evaluated using microsatellite polymorphisms in the 3' untranslated region of WT1 in a radioactive PCR assay. The study comprised 66 children (30 girls and 36 boys), aged from 2 days to 13 years, treated for Wilms' tumour according to the SIOP-09 and PGGL scheme. We have used DNA isolated from the neoplastic versus normal kidney tissue from the paraffin embedded sections using microdissection procedure. Loss of heterozygosity (LOH) of the WT1 gene was found in 12 children (19.6%), 5 cases were noninformative. No significant correlation could be found between the LOH of WT1 gene and sex and age. Significantly more frequent occurrence of LOH in tumor in low stage of advancement and low degree of malignancy was found. However; no significant effect of LOH of WT1 gene was observed on frequency of recurrences, metastasis and deaths. Study of allele loss of the WT1 gene may be recommended in difficult cases as an additional factor useful for the diagnosis and in the assignment of the tumour to the appropriate risk group.