Heterogeneity of DNA distribution pattern in renal tumours

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