Pulse cytophotometric measurements on tumor cell suspensions and exfoliative material.

By impulse cytophotometry (ICP) it is possible to get a DNA-distribution curve of nuclei in cell suspensions. The ICP curve directly represents the ploidy pattern of the investigated cell population and, more indirectly the proliferation intensity. For practical tumor diagnosis in cytology by ICP as a first step we must know, wether the ICP is able to detect differences between normal and tumor cells by simple criteria. Together with our clinical coworkers we had investigated cell suspensions from carcinomas of the cervix, ovary, breast, larynx, stomach and malignant melanomas. Approximately one half of these tumors were poly- or aneuploid. In the remaining diploid tumors some did not show signs of strong proliferation in the form of high 4c-peaks in the ICP; for these the chances of detecting by ICP in exfoliative material are low. This is in agreement with our results on vaginal smears. Here we had a good correlation between the mean 4c-height of the ICP curves and the Papanicolaou grading. But mass screening is not the main application of ICP because the security of Pa-grading is more sufficient. In individual problematic cytological cases with repeated investigation ICP is a very valuable diagnostic aid.