Aging of stromal-derived human breast fibroblasts might contribute to breast cancer progression.

Age is an important factor in the development and spread of breast cancer. Stromal cells also contribute to breast cancer growth and metastasis through the production of extracellular matrix (ECM) modifiers such as urokinase type plasminogen activator (uPA), its receptor (uPAR), its inhibitors (PAI-1 and PAI-2), matrix metalloproteinases (MMPs), and growth factors, including the fibroblast and insulin-like growth factors (FGF's and IGF's). In the present study we have investigated whether breast fibroblasts aged in vitro through passage in culture display altered levels of the plasminogen activator system and growth factors that are known to modulate that system.