Flow cytometric analysis of DNA-aneuploidy subgroups and proliferation in renal cell carcinoma

Background: the course of patients suffering from renal cell carcinoma varies considerably and cannot be predicted by tumor stage and grade alone. However, it is crucial to select patients with high risk of progression and to commence adjuvant immuno-chemotherapy in good time. Materials and Methods: Multiple samples of 71 kidney tumors were studied by DNA flow cytometry. aneuploidy was classified into subgroups employing the DNA-index. In tumors of euploid pattern and corresponding normal tissue cell cycle analysis was performed. Results: 39% of tumors were found to be aneuploid. Mean proliferation fraction was distinctly higher in euploid tumors (15.6%) than in normal tissue (6.1%). DNA ploidy pattern correlated significantly (p < 0.05) with histological grading. With increasing tumor size the clonal spectrum changed as well: Tetraploid cell lines fell from 40% to 28%. The number of triploid clones rose from 33% to 56%. Conclusion: Based on selection of tri- and hypertetraploid carcinomas, a high-risk-group for tumor recurrence can be associated within the predominating T2/3 G2 kidney tumors. The aim is to treat these patients following curative surgery at the stage of probable micro-metastases while keeping risk of overtreatment as low as possible.