DNA analysis (ploidy) of molar pregnancies with image analysis on paraffin tissue sections

Hydatidiform moles can be subclassified based on their ploidy. In general, complete moles are diploid, and partial moles are triploid. The standard method for the determination of DNA content is flow cytometric analysis. In this study, the authors investigated whether static cytometric analysis with the CAS 200 Image Analyzer (Cell Analysis Systems, Inc., Elmhurst, IL) with a software program designed for quantitation of nuclear DNA content in tissue sections can be used to classify moles. Tissue sections from 17 moles were analyzed with this system, and the results were compared with those obtained with flow cytometric analysis. It was found that cell selection was an important factor. A high proportion of the hyperplastic trophoblast was in G2M. Exclusion of these areas and measurement of the trophoblast lining the villi only led to reliable results, and complete agreement between the results of the two methods was obtained. The findings indicate that cytometric analysis on tissue sections is a reliable alternative to flow cytometric analysis for the designation of moles as diploid or triploid.