Recent progress in clinical quantitative cytology.

The last several years have seen changes in quantitative cytologic procedures that have significantly expanded the clinical research and diagnostic applications of quantitative cytologic analysis. Intact nuclei can be isolated from formalin-fixed paraffin-embedded tissue, and the DNA distribution of these nuclei can be analyzed either with flow cytometry or with slide-based image-processing techniques. In addition, more informative DNA analysis has been achieved using antibodies to bromodeoxyuridine-modified DNA, proliferation-associated nuclear antigens, or tissue-type-specific cytoplasmic antigens as second stains for two-parameter analysis. Improvements in both staining and instrumentation have also increased the usefulness of flow cytometry in analysis of "rare events," ie, cell types comprising less than 0.1% to 0.5% of a total cell suspension. Commercially available slide-based image-processing systems have been developed that provide sophisticated cell and tissue analysis functions using inexpensive personal-computer-based systems.