Background:
The plasminogen activator system plays an important role in different malignant tumors. these enzymes participate in the destruction of intercellular matrices and basement membranes and/or can modulate the growth potency of tumor cells and may even promote metastases. in this study, the expression of three glycoproteins that play a role in the plasminogen activator system as activators of proteolysis-urokinase type plasminogen activator (u-pa), tissue type plasminogen activator (t-pa), and plasminogen activator inhibitor type 1 (pai-1) were studied in various components of dedifferentiated chondrosarcomas of bone.
Methods:
The expression of u-pa, t-pa, and pai-1 was investigated in 10 dedifferentiated chondrosarcomas and 14 conventional chondrosarcomas. the plasminogen activator/inhibitor glycoproteins were visualized immunohistochemically on paraffin sections and the levels of expression were assessed semiquantitatively.
Results:
In dedifferentiated chondrosarcoma, high grade dedifferentiated components displayed strong, diffuse coexpression of u-pa, t-pa, and pai-1. for all glycoproteins studied, the immunoreactivity was significantly increased compared with the reactions in the low grade cartilaginous component of the same tumor and conventional chondrosarcoma. in the latter, u-pa, t-pa, and pai-1 expression was found to be enhanced at invasive foci and in regions of endochondral ossification.
Conclusions:
The current study documents the overexpression of u-pa, t-pa, and pai-1 in dedifferentiated chondrosarcoma and suggests involvement of the plasminogen activator system in the biology of these tumors.