PROLIFERATIVE CELL INDEXES MEASURED BY DNA FLOW-CYTOMETRY IN NODE-NEGATIVE ADENOCARCINOMAS OF BREAST - ACCURACY AND SIGNIFICANCE IN CYTOKERATIN-STAINED ARCHIVAL SPECIMENS

Proliferative rates of 73 node-negative adenocarcinomas of breast with 5-year or greater follow-up were studied using cytokeratin staining i n two-parameter DNA flow cytometry of archival specimens. Quality cont rol data of accuracy of the measurements were determined and all analy ses were compared with single-parameter results of the same specimens, using demarcated tumor areas, quadruple analyses, and computerized no nspecific staining subtraction. Mitotic rates of the same samples corr elated highly significantly with the S-phase fractions and proliferati ve index (S + G(2) + M phases), especially for the cytokeratin data. T he predictive value of mitotic rates was found significant, but that o f the DNA flow-cytometry-obtained indices was not, probably because of low numbers of deaths in this study. The cytokeratin method identifie d heteroploid tumors containing a diploid cell population not identifi able by single-parameter analysis. In conclusion, cytokeratin staining can be reliably applied to DNA flow cytometry of archival specimens g iving accurate ploidy, S-phase fractions, and proliferative index data limited almost exclusively to neoplastic cell populations. This will permit large-scale retrospective studies aimed at establishing the use fulness of DNA flow cytometry for clinical decisions on therapy of sur gically removed node-negative adenocarcinomas of breast.