To validate in vivo the data obtained in kidney cancer cells, we generated a praja2 knockout (KO) mouse model, by Cre/LoxP approach, targeting the exon2/3 region of the genomic locus with a LoxP (L83) site and a FNFL (Frt- Neo-Frt-LoxP) cassette (Fig. 8a). The gene discussed is FLT1; the disease is kidney cancer.