[Nephroblastoma (Wilms' tumor): cytogenetic and molecular biology principles].

As in retinoblastoma, the development of nephroblastoma (Wilms' tumor) seems to be the consequence of inactivation of one or several tumor suppressor genes. Various cytogenetic studies lend support to the hypothesis that 11p is the chromosomal region most likely to be involved in the pathogenesis of Wilms' tumor. By means of recombinant DNA techniques the candidate regions for localization of potential tumor suppressor genes were narrowed down to 11p13 and 11p15. Furthermore, a third potential suppressor gene is suspected on another chromosome. Recently, the tumor suppressor gene localized on 11p13 has been cloned and characterized: WT1 encodes for a polypeptide with DNA binding capacity and is potentially involved in the regulation of the expression of several genes associated with kidney growth and differentiation. Therefore, inactivation of WT1 could lead to altered expression of these genes enhancing their mitogenic potential.