Loss of chromosomes in clear cell renal cell carcinoma and in corresponding renal parenchyma.

: Chromosome studies were done on six renal cell carcinomas (RCC) and on the corresponding renal parenchymas of the tumor bearing kidneys. Histopathologically, all tumors belonged to the clear cell subtype. All examined parenchymas were pathologically benign. None of the tumor cells showed the typical chromosomal aberrations described for (nonpapillary) RCC, i.e. deletions in the short arm of chromosome #3, or gains in the long arm of chromosome #5. In our series both the tumor and the benign kidney tissues were characterized by loss of chromosomes, especially of the chromosomes #6, #9, #16, #20, and of the Y chromosome. Trisomy of chromosome #7 was found frequently in benign parenchyma cells. The identical chromosomal changes in the tumor and in the parenchyma tissues might reflect rather in vivo mosaics rather than primary chromosomal aberrations in the oncogenetic process of clear cell RCC.