Flow cytometry and cytomorphology in primary resectable breast cancer.

Using flow cytometry for DNA analysis, ploidy and proliferative activity were measured in 43 cases of primary resectable breast cancer, 24 of which were also assayed for estrogen receptors. Tumors were studied histopathologically by multiple samples and cytopathologically by means of imprint smears and pepsinized cell suspensions. Cytologic preservation was far superior in imprint smears than in cell suspensions or histologic sections. As determined by the DNA index (tumor G1/G0:normal G1/G0), 72% of the tumors were aneuploid, with the majority falling between diploid and tetraploid. There was no correlation of ploidy with tumor cell proliferation expressed as percentages in the S-phase. A high percentage of S-phase cells was associated with estrogen receptor negativity and tended to correlate with cytologic atypia but showed no correlation with UICC stage, menopausal status, tumor size, lymph node involvement or histologic degree of malignancy. In contrast, ploidy showed no correlation with any of the above parameters but served as a reliable marker for individual tumors since it did not change with time in multiple biopsies of the primary site.