I've seen in a comment that people are performing flow cytometry in FFPE samples, but I thought the cells should be alive to do it, isn't that right? How does it work?
When I first read the question I was sceptical if I really understood the question, but it seems to be an interesting method to analyze old, archival material - and to better enrich for real tumor cells and separate them from normal tissue and immune cells.
I did not do the experiment, but I know the techique is used nuclei instead of alive cells to do cytometry analysis.
Corver WE et al. High-Resolution Multiparameter DNA Flow Cytometry for the Detection and Sorting of Tumor and Stromal Subpopulations from Paraffin‐Embedded Tissues. https://doi.org/10.1002/0471142956.cy0737s55
Hedley DW, et al. Method for analysis of cellular DNA content of paraffin-embedded pathological material using flow cytometry. J Histochem Cytochem 1983, 31:1333-1335