Tissue plasminogen activators in breast cancer

Area of Science:

• Biochemistry
• Oncology
• Molecular Biology

Background:

• Fibrinolytic activity is elevated in some malignant tumors, potentially aiding metastatic spread.
• Tissue plasminogen activator (tPA) and urokinase (UK) are key components of the fibrinolytic system.

Purpose of the Study:

• To investigate the levels and localization of tPA and UK in breast carcinomas and benign breast biopsies.
• To determine if altered fibrinolytic activity is associated with malignant transformation in breast tissue.

Main Methods:

• Analysis of tissue extracts for fibrinolytic activity using fibrin plates and zymography.
• Quantification of tPA and UK using antigenic immunoassays (ELISA) and functional bioimmunoassays (BIA).
• Comparison of enzyme levels between 26 breast carcinomas and 13 benign breast biopsies.

Main Results:

• All tissues exhibited similar levels of tPA.
• Malignant breast extracts showed significantly higher UK levels compared to benign extracts (P < 0.002).
• Zymography confirmed UK was predominantly present in malignant tissues.

Conclusions:

• Malignant transformation of breast tissue is associated with significantly increased urokinase (UK) production.
• Elevated UK may play a role in the characteristics of malignancy or function as a growth factor.