Abnormal RNA expression of 11p15 imprinted genes and kidney developmental genes in Wilms' tumor.

Abstract

Wilms' tumor (WT) is caused by abnormal development of embryonal kidney cells. WT cells are frequently affected by deletions or functional inactivation of maternal alleles at chromosome 11p15, which indicates that the loss of maternally expressed genes in this region plays an important role in WT pathogenesis. Maternally expressed genes indeed exist within an imprinted region at 11p15.5. Among these, BWR1C is highly expressed in fetal but not in adult kidney, which suggests that it may fulfil an important role in kidney development. Here, we demonstrate that the lack of BWR1C expression is common in WT. Its homology with the proapoptotic gene TDAG51 suggests that the loss of BWR1C expression may be relevant in WT development. In addition, the analysis of the expression of other 11p15 imprinted genes and kidney-developmentally regulated genes indicates that IGF2 overexpression, inappropriate coexpression of RET and GDNF and, in some cases, down-regulation of CDKN1C may also play an important role in the pathogenesis of WT. Our results add new elements to the understanding of the biological basis of WT, which may have implications for WT diagnosis and therapy.