[S-phase fraction of benign mastopathies and breast carcinomas].

The S phase fraction of breast biopsies of 110 patients determined in vitro using 3H-thymidine. In fibrocystic lesions the 3H-thymidine labeling index (3H-TMI) increases parallel to the degree of dysplasia. In our opinion proliferating mastopathies are only those with a 3H-TMI of more than 1%. Invasive ductal mammary carcinomas with the histological structure demonstrate a strong variable proliferative activity histoautoradiographically as expression of their different growth dynamics.