HETEROGENEITY OF DNA DISTRIBUTION PATTERN IN RENAL TUMORS

The presence of intratumoural heterogeneity in DNA distribution patter ns has been accepted. However, most previous studies have not taken th is fact into consideration. The value of DNA cytometry depends on its reproducibility. This could be influenced by heterogeneity failure. Th e aim of the present study is to evaluate intratumoural heterogeneity in renal cell cancer. A sample of 22 tumours of the kidney was investi gated by means of static DNA cytometry: 21 tumours were carcinomas, on e was an angiomyolipoma. Probes from seven different locations of each tumour were Feulgen-stained and measured. The variability of DNA feat ures was determined and correlated with histological grade and type an d with tumour size. There was considerable intratumoural heterogeneity with respect to DNA distribution pattern in 45% of the tumours. Addit ional non-diploid tumour-stemlines and deviation of computed DNA featu res could be found in several cases by measuring more than one slide p er tumour. A correlation between tumour heterogeneity, grading or typi ng, and tumour size could not be found. Because these DNA parameters c ould serve as the foundation of a risk-adapted treatment, tumour heter ogeneity could have clinical consequences. Based on the results of thi s study we suggest measuring at least three slides per tumour to avoid misinterpretation of DNA measurements in renal cell cancer.