A retrospective study of DNA ploidy of transitional cell carcinoma of urinary bladder using flow cytometry.

Transitional cell carcinoma is the most common malignancy of urothelial origin in urinary bladder. Its aggressive potential cannot be reliably predicted from the histologic appearance alone. Recently, there has been extensive studies of DNA ploidy using flow cytometry in prospective analysis of bladder tumors with fresh tissue. Techniques for the preparation of paraffin embedded tissue have been developed and successfully applied in retrospective evaluation of bladder tumors. These studies had demonstrated the correlation between histological grading and DNA ploidy, and between clinical staging and DNA ploidy. Our retrospective study showed that the cytometric method is superior to histologic grading in the predictability of patient's survival, especially in the low grade (grades 1 and 2) group. In the preparation of paraffin embedded tissue, the high background debris and wide range of coefficients of variation had some interference in the interpretation for the histogram of FCM (only 80% of the cases studied are interpretable). This interference might be due to the variation of conditions of tissue processing and fixation. The evaluation of S phase fraction and G2/M fraction is also difficult to perform because of the same problem. There was an encouraging result in the evaluation of DNA ploidy using flow cytometry with paraffin embedded tissue, although a relatively small number of patients were included in this study. The value of this technique application in clinical evaluation of the prognosticity was obvious.