DNA cytophotometry in renal cell carcinoma: a significant prognostic factor?

We report on a prospective DNA cytophotometric study of 66 patients with renal tumors, 61 of whom had renal cell carcinoma (RCC) (pT1-pT4, G1-G3). 16 of the patients had a metastasis at the time of diagnosis. Cell material from 1-5 specimens of each tumor was analyzed for intratumoral heterogeneity. The aim of the study was to evaluate the prognostic value of the following DNA parameters: DNA ploidy, DNA grade of malignancy (DNA MG), mean DNA, DNA index, 2c deviation index (2cDI), and 5c exceeding rate (5cER). In this study 21% of the tumors were non-aneuploid, 79% were aneuploid; however, it proved possible to diagnose 38% of the total collective as aneuploid only by analyzing several tumor areas. In five of 61 RCC patients who died during an observation period of 42 months, at least one area of the primary tumor was aneuploid. Aneuploid primary tumors also accompanied the development of metastases and recurrent tumors in four of the 61 RCC patients. Only DNA 2cDI was found to have a significantly positive clinical correlation with metastasis (r = 0.261) during the clinical course. This was not true, however, for the histopathologic parameters. Significantly positive correlations were found between the tumor stages and the following DNA parameters: mean DNA, DNA index, and 5cER. Histopathologic tumor grading showed a significantly positive correlation with DNA MG, mean DNA, and 5cER. Statistically, the mean values of all evaluated parameters were significantly higher in metastasizing and recurrent RCCs than in non-metastasizing carcinomas (p < 0.05; t-test). DNA cytophotometry cannot substitute histopathologic prognosis. However, the analysis of various DNA parameters helps considerably in evaluating both the malignant potential of kidney tumors and the benign parenchyma of tumor-bearing kidneys.

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.