Relationship between tumorigenicity, in vitro invasiveness, and plasminogen activator production of human breast cell lines.

Two human breast epithelial cell lines (HBL-100, HMT-3522) of non-malignant origin and six (MCF-7, T47-D, ZR-75-1, CAMA-1, BT-20, HMT-3909) of malignant origin have been studied to evaluate whether in vitro invasion and/or secretion of urokinase-type plasminogen activator are related to tumorigenicity in athymic nude mice. Only the six cell lines of malignant origin were tumorigenic. Two of these were invasive in the in vitro assay. These two cell lines were oestrogen receptor negative. Three of the other four cell lines of malignant origin contained oestrogen receptors. The two cell lines of non-malignant origin were neither tumorigenic nor invasive. Thus tumorigenicity was correlated to malignant origin of the cell line whereas invasiveness in vitro was a property of the most undifferentiated cell lines of tumor origin. Secretion of urokinase-type plasminogen activator was neither correlated to tumorigenicity nor to invasion in vitro nor to malignancy of tissue origin.