It is difficult to explain the significance of this finding, and if these cystic lesions may represent very early cancer lesions, but this observation gains in significance in the light of the case described by Kuiper et al. who identified in an adult patient affected by a RCC a familial constitutional translocation t(3;4)(q21;q31) disrupting the FBXW7 gene at 4q but no genes at 3q9. This evidence concerns the gene FBXW7 and cancer.