Image Analysis Confirmation of DNA Aneuploidy in Flow Cytometric DNA Distributions Having a Wide Coefficient of Variation of the GO/G1 Peak

Abstract

With nuclei extracted from paraffin-embedded tissues, resolution of normal diploid DNA and abnormal near-diploid/aneuploid populations by flow cytometry (FCM) is especially difficult. These samples, compared with fresh tissue, tend to show a broader DNA distribution, appearing as a wide (high) coefficient of variation (CV) of the GO/Gl peak. To address the question of whether there may be aneuploid populations hidden in wide CV diploid GO/Gl peaks, the authors measured DNA content in nuclei extracted from paraffin-embedded tumor tissue by morphometric image analysis (IA) in addition to FCM. Of 29 samples showing little evidence of DNA aneuploidy by FCM, in 20 of 20 with GO/Gl CVs greater than or equal to 5.50% there was an aneuploid population when analysis was performed by IA. Of the remaining nine samples with CVs less than or equal to 4.41%, all were diploid in the GO/Gl region by both FCM and IA. The presence of aneuploid populations in FCM distributions with wide CV GO/Gl peaks can be confirmed by IA.