Interpretation guidelines of DNA histograms from tissue sections of breastcancer

Background: Evaluation of nuclear DNA staining intensity from histological breast cancel sections has not always is been accepted because of the diffi culties in interpreting the histograms. One reason for this is the lack of evidence based interpretation guidelines. Materials and Methods: The DNA st aining intensity of 140 breast cancer samples was measured with flow cytome try. (FCM) and image cytometry (ICM). The methods were compared by ruing gr ading efficiency (GE). Result: First, the ICM histograms were evaluated wit h a computer assisted image cytometry system using different cut off points for aneuploidy. The GE results varied from 679-76.4%. Subjective interpret ation and evaluation according two previously published interpretation meth ods did not improve the GE. Secondly we excluded histograms which showed cl early different cell clones in FCM and ICM. The GE of remaining histograms was 77.9%. Comparison of these histograms allowed formulation of interpreta tion guidelines which improved the GE to 85.3%. Conclusions: This study sug gests that efficient interpretation guidelines of section-based DNA histogr ams can be created.