The applications of the BrdUrd-technique for the estimation of cycling S-phase cells in human renal cell carcinoma.

After testing the BrdUrd technique on experimental tumour cell lines, we applied the technique to human renal cell carcinoma in vitro. We compared the results with the data acquired after FCM analysis and 3H-thymidine treatment. In contrast to BrdUrd the 3H-thymidine uptake seemed to be limited in suspended cells. FCM data represented the DNA distribution of cells. BrdUrd labelling on the other hand detected DNA synthesizing cells. Only both methods in parallel were able to discriminate between proliferating cells and resting cells with an S-phase equivalent DNA content.