[Cell kinetic investigations in fibrocystic mastopathies and invasive breast carcinomas].

The thymidine labeling index (TLI) was measured in tissues from 64 women with fibrocystic changes, fibroadenomas and invasive breast carcinomas by an in vitro method. The lesions were classified according to Prechtel and Hutter. Per patient a total of about 5000 cells were counted from five different regions. The TLI in Mastopathia (MP) I was 0.23 +/- 0.16 (mean +/- SD), in MP I-II 0.43 +/- 0.40, in MP II 0.77 +/- 0.41, in MP III 0.99 +/- 0.67, in fibroadenomas 0.87 +/- 0.49 and in carcinomas 3.44 +/- 2.04. These results underline the proliferative heterogeneity of different forms of fibrocystic conditions. Their relative risk for the subsequent development of invasive breast cancer seems to be low but different. The variable labeling indices of breast cancer express the different growth rate of the tumors. Labeling indices, flowcytometric data and immunohistochemically detected Ki-67-growth fraction show a similar behaviour. Results of cell kinetic studies could contribute for characterization of human breast carcinoma and their preneoplasias.