FLOW AND IMAGE CYTOMETRY FOR DNA ANALYSIS IN BLADDER WASHINGS - IMPROVED CONCORDANCE BY USING INTERNAL REFERENCE FOR FLOW

Using flow or image cytometry, we compared the DNA distribution of cel ls from bladder washings from 52 patients with bladder cancer. For ima ge cytometry, urothelial nuclei (recognized visually) were analyzed fo r DNA content using polymorphonuclear nuclei as internal diploid refer ence. For flow cytometry, two methods can be used: either all cells ca n be analyzed, as commonly performed, or urothelial cells can be analy zed alone, after specific detection. In this flow cytometry study, cel ls were doubly stained for panurothelial antigen T16 and for DNA. All the cells were first analyzed using peripheral lymphocytes as an exter nal reference; 79% of the results were similar with results obtained f rom image analysis. For discordant results, flow-cytometric data were reprocessed to identify immunologically stained urothelial cells; one additional case became concordant with image cytometry when only uroth elial cells were analyzed, with lymphocytes as diploid reference; a be tter concordance (94%) was found when the nonurothelial cells of the s amples served as a diploid reference instead of peripheral lymphocytes . This suggests that we achieved an improvement of the flow-cytometric evaluations for ploidy assessement, and we conclude that, on these co nditions, flow or image analysis can be considered as equivalent metho ds for DNA content studies of tumors. (C) 1993 Wiley-Liss, Inc.