A COMPARATIVE-STUDY OF DNA CONTENT AS MEASURED BY FLOW-CYTOMETRY AND IMAGE-ANALYSIS IN 1864 SPECIMENS

Both flow cytometry (FCM) and image cytometry (ICM) were used to asses s the DNA content of 1864 lesions (benign and malignant tumors, dyspla sias, dystrophies and normal tissue). In total there were 1274 cases o f bladder washings and 590 fresh solid tumor specimens. Of the total n umber of specimens, 1737 (93.2%;) were satisfactorily assessed by ICM and 1424 (76.4%) by FCM. In only 100 (5.4%) cases was the DNA content unable to be assessed by either method. When bladder washings were exc luded, 99.5% of samples could be evaluated by one method or the other. Concomitant determinations with both technologies were made in 1397 c ases. When comparing all evaluable cases, concordance between the ploi dy measurements of FCM and ICM was 92.8% (1297 concordant cases out of 1397). When bladder washings were excluded and only solid tumors cons idered, the concordance was 96.1% (545 concordant cases out of 567). F rom the experience of applying ICM and FCM to the 1864 lesions the tec hnical limitations of each method became evident, specifically the pro blems of doubtful DNA diploidy and doubtful DNA aneuploidy. When there were 'doubtful' ploidy findings, the cause was generally found to be morphologic alterations of the nuclei or differences in staining proce dures employed, and often the complementary use of both FCM and ICM pr ovided ploidy clarification in questionable cases.