[PAX gene function during kidney tumorigenesis: a comparative approach]

The rising incidence of cancers affecting the kidney emphasizes the need to identify the molecular pathways involved in the initiation and progression of kidney tumors in order to counter this phenomenon. For many years, genes belonging to the PAX family have been the focus of intensive studies in the fields of organogenesis and tumorigenesis. PAX2 and PAX8 encode transcription factors essential for embryonic kidney development. Transcriptionnal repression of these factors is, however, required to allow terminal differentiation of renal epithelia. In human, maintenance and reactivation of PAX2/8 expression are frequently observed in cases of Wilm's tumor and renal cell carcinoma. The precise role of PAX2/8 in kidney cancer is still elusive but results from several studies suggest the exertion of common functions during organogenesis and tumorigenesis of the kidney. Moreover, many members of the PAX family are involved in similar cellular processes such as differentiation/proliferation, motility and apoptosis. Thus, by comparing the functions exerted by PAX factors in several types of cancers should be useful to better define the specific contribution of PAX2/8 to kidney tumorigenesis.