MULTIPARAMETER ANALYSIS OF DNA CONTENT AND CYTOKERATIN EXPRESSION IN BREAST-CARCINOMA BY LASER-SCANNING CYTOMETRY

Objective.-The objective of this study was to test a new laboratory te chnology, laser scanning cytometry, for the purpose of performing mult iparameter DNA content analysis of breast carcinomas. Design.-We devel oped a simplified method of multiparameter DNA content analysis using cytokeratin expression to positively gate epithelial cells. Over 300 c onsecutive cases of breast carcinoma were analyzed by multiparameter l aser scanning cytometry. The first 73 cases were analyzed in parallel by single parameter flow cytometry. Setting.-The Department of Patholo gy, Christ Hospital and Medical Center, Oak Lawn, III. Specimens.-Thre e hundred eighteen consecutive cases of breast carcinoma presenting be tween March 1994 and Decemberl995. Main Outcome Measures.-Outcome meas ures included the percentage of cases for which DNA content analysis c ould be successfully performed given the limitations of specimen size. Additionally, for the first 73 cases, laser scanning cytometry result s were compared with flow cytometry results. Results.-All of the first 73 cases were successfully analyzed by laser scanning cytometry, but for 8 cases (11%) there was insufficient material for flow cytometry. Correlation of DNA content for the remaining 65 cases analyzed in para llel by the two methods was nearly perfect (p = .994). Five seemingly discrepant cases highlighted the importance of cytokeratin gating of e pithelial cells by any technique, as well as other advantages specific to laser scanning cytometry, such as the ability to examine individua l cells microscopically and correlate cytologic morphology with DNA co ntent results. Conclusions.-Laser scanning cytometry is a promising ne w technology for DNA content analysis of solid tissue tumors. Further work needs to be performed to validate the prognostic potential of the laser scanning cytometric assay results and to generate methodologies aimed at providing highly objective determinations of tumor cell S-ph ase fraction.