Comparison of DNA measurement performed by flow and image cytometry of embedded breast tissue sections

Tissue sections are important for morphometric studies, such as the analysis of architectural pattern of tissues as well as nuclear morphology and chromatin texture describing DNA distribution in nuclei. Tissue sections are generally not recommended for use in DNA ploidy measurements due to possible errors based on sectioned and overlapped nuclei. However, image cytometry (IC) on tissue sections has the advantage of preserved architecture and selective sampling of nuclei. This is particularly important for the analysis of specimens with small areas of diseases tissue or with a variety of histologic patterns in the same region, such as premalignant changes or in situ tumors. To evaluate the potential of measurements on breast tissue sections in the estimation of DNA ploidy status, we compared IC and flow cytometry (FC) measurements on formalin-fixed breast cancer tissue from 51 paraffin-embedded blocks. For each specimen the DNA index and ploidy were determined by both methods. DNA indices of IC and FC corresponded roughly in 66% of cases. Agreement in ploidy was achieved in about 80% (40/51) of cases, where some of the discrepancies could be explained by the differences between invasive cancer and ductal carcinoma in situ (DCIS) illustrated by IC. Both methods agreed highly in aneuploid cases. However, about 50% of FC diploid cases were aneuploid by IC. Despite significant shortcomings of measurements obtained on archival tissues, meaningful data can be obtained not only by FC but also by IC performed on tissue sections.(ABSTRACT TRUNCATED AT 250 WORDS)