We have established a chicken model for high-throughput identification of genes directly involved in the genesis and progression of renal tumors and of solid tumors in general.The model is based on in vivo insertional mutagenesis by the MAV2 retrovirus resulting in clonal outgrowth of the transformed cells.Early infection of chicken embryos or hatched chickens with the MAV2 retrovirus leads almost exclusively to clonal macroscopic nephroblastomas arising between 2nd and 3rd months of age.We assembled and characterized a collection of more than 300 independent nephroblastomas.Analyses of more than 1000 independent clonal MAV2-integration sites in selected tumors revealed about 60 gene loci hit by MAV2 integration morethan once; these loci can thus be referred to as common integration sites.The viral integration into the most frequently hit locus does not exceed 7%, pointing to the ability of the model to reveal a plenty of potential oncogenes.Genes deregulated in the vicinity of these sites are candidate oncogenes.