DNA flow cytometric values in bladder carcinoma biopsies obtained from fresh and paraffin-embedded material.

DNA-histograms were obtained by flow cytometry (FCM) of nuclei prepared from fresh bladder carcinoma biopsies and from 100 micron sections of paraffin-embedded material from the same biopsies. Linear regression analysis of ploidy values from fresh material versus those from paraffin blocks showed excellent correlation (R2 = 0.957). Owing to the high background, the paraffin-embedded material was less suited for analysis of S-phase fraction. It is concluded that DNA FCM of nuclei obtained from paraffin-embedded bladder carcinoma biopsies yields reliable results concerning ploidy, but does not permit evaluation of the S-phase fraction.