Measurement of bromodeoxyuridine labeling index, Ki-67 score and Ag-NOR count in breast carcinomas. Comparison with DNA ploidy.

Nuclear DNA content and three cell proliferation markers, the bromodeoxyuridine (BrdUrd) labeling index, Ki-67 score and Ag-nucleolar organizer region (Ag-NOR) counts, were measured in 21 cases of breast carcinoma, and then relationships among them were investigated. The BrdUrd labeling indices and Ki-67 scores were strongly correlated with one another (r = 0.90, p less than 0.001). They were also slightly correlated with the Ag-NOR counts (p less than 0.05). Although growth activity varied greatly from case to case, even within the same histologic grade in breast carcinoma, high histologic grade carcinomas were frequently associated with high values of both the BrdUrd labeling index and Ki-67 score, as compared with low histologic grade ones. The DNA ploidy level (DNA index) was independent of these cell proliferation markers. In the present series, 17 of 21 cases (81%) were aneuploid. All cases without DNA aneuploidy fell into a group of low histologic grade, while 7 of 11 low grade tumors were aneuploid. All three cell proliferation markers were low in 2 of the 4 cases without DNA aneuploidy. It may be possible to identify cases with favorable prognosis in a group of low grade carcinomas on the grounds of diploid DNA content and low values of these markers.