QUANTITATIVE DNA ANALYSIS IN BREAST CARCINOMAS - A COMPARISON BETWEEN IMAGE-ANALYSIS AND FLOW-CYTOMETRY

We compared the results of quantitative DNA analysis of fresh tumor tissue from 50 invasive breast carcinomas by image analysis and flow cytometry. For image analysis, Feulgen-stained slides of tumor imprints and of disaggregated tumor cytospin preparations were evaluated with the CAS-200 image analyzer. For flow cytometry, propidium iodide-stained disaggregated tumor cells were analyzed with the Coulter EPICS-C flow cytometer. The two methods yielded comparable results. The DNA indices obtained by the two methods showed close correlation by linear regression analysis (r = 0.86, P < 0.001). There were 26 diploid (52%) and 24 nondiploid (48%) carcinomas. The ploidy pattern between the two methods showed agreement in 41 carcinomas (82%) and discordance in two (4%). Three tumors (6%) were equivocal by flow cytometry and four (8%) by image analysis. The equivocal cases presented potential sources of error in the evaluation of histograms in the near-tetraploid region by flow cytometry and in the near-diploid region by image analysis. Image analysis required smaller tissue samples and permitted direct visualization and selection of tumor cells. It also detected more tetraploid carcinomas. In contrast, flow cytometry analyzed larger cell samples and provided histograms with better resolution. It more readily detected the presence of multiple aneuploid peaks and also the presence of aneuploid peaks in the near-diploid range. The presence of aneuploidy was significantly related to the loss of hormone receptor expression, high mitotic rate, and high histologic and nuclear grades. Our study indicates that image analysis and flow cytometry provide comparable results in a majority of breast carcinomas. They offer individual advantages and are complementary techniques for analyzing DNA ploidy in breast carcinomas.