Measurement of markers for breast cancer in a model system using laser scanning cytometry

Background: A variety of markers, including Ki67, estrogen receptors (ER), and progesterone receptors (PgR), are frequently measured in fine needle as pirates (FNA) from human breast carcinomas. We used a human breast carcinom a cell line. MCF7, as a model system to investigate the use of laser scanni ng cytometry (LSC) for the measurement of these markers. Additionally, we m easured the number of apoptotic cells. Methods: Cells were treated with drugs to vary the expression of markers an d the number of apoptotic cells. They were then fixed on microscope slides. For LSC, the cells were stained for the different markers with fluorescein using immunofluorescence and for apoptotic cells using the TUNEL assay. Th e nuclei were counterstained with propidium iodide. A parallel set of slide s was stained using horseradish peroxidase and diaminobenzidine and scored manually by conventional light microscopy. Results: The results from the LSC closely paralleled those obtained by manu al scoring of immunohistochemical stains. Conclusions: It should be possible to use LSC for the routine measurement o f nuclear markers in FNAs from human breast carcinomas. (C) 2000 Wiley-Liss , Inc.