Cytogenetic studies and DNA analysis have shown that the short arm of chromosome 3 is the region in the genome that is commonly deleted in renal cell carcinoma. By studying loss of heterozygosity in 41 matched tumor/normal kidney tissue pairs, we could delimit the commonly deleted part of 3p to the region between the loci THRB (in 3p24) and D3S2 (in 3p21). The regions on 3p suggested to be involved in the Von Hippel-Lindau syndrome and in hereditary renal cell carcinoma are both outside this smallest region of overlapping deletions. Consequently, renal cell cancer would be an illustration of the possibility that different genes cause the same type of tumor.