Deoxyribonucleic acid measurements in transitional cell carcinomas: Comparison of flow and image cytometry techniques

Purpose: We compared the results of deoxyribonucleic acid (DNA) ploidy determinations performed by flow cytometry and image cytometry in transitional cell carcinomas of the bladder. Materials and Methods: In 81 cases of transitional cell carcinoma of the bladder DNA indexes were measured by flow cytometry of bladder washings and tumor tissue samples, and by image cytometry of imprints from tumor tissue samples. Results: There was good correlation between bladder washings and tissue samples analyzed by flow cytometry in 68 cases but aneuploidy was missed with bladder washings in 13 (16%). There was also good correlation between flow and image cytometry in 75 cases (92.59%) regarding the detection of aneuploidy. There was agreement between detection of aneuploidy and DNA index in 45 cases (55.5%), while both methods detected an aneuploid population in 30 (37%) but there was disagreement regarding DNA index. Aneuploid populations were missed by flow cytometry in 6 cases (7.4%). Furthermore, in 10 cases peridiploid peaks were found on the image cytometry histograms, which were not visible on flow cytometry. However, it was not possible to assess accurately if these were true peridiploid populations. Conclusions: There is good overall correlation between DNA content measured by flow and image cytometry but image cytometry has the advantage of visual discrimination, permitting preferential selection and analysis of tumor cells. However, certain problems remain with image cytometry, particularly in the case of peridiploid peaks, which cannot be classified accurately as showing true peridiploid or right shifted diploid populations.