Cathepsin D and PAI-1 expression in human head and neck cancer.

In order to determine possible overexpression of cathepsin D and PAI-1 (plasminogen activator inhibitor) in head and neck tumours, cytosols from 92 primary squamous cell carcinomas (SCC), 19 lymph node metastases and 24 adjacent normal tissue samples were examined. For both cathepsin D and PAI-1, significantly elevated concentrations in SCC compared to normal tissue were found, even in pairwise comparison. Moreover, significantly higher cathepsin D and PAI-1 concentration in lymph node metastases than in corresponding normal tissue were also present. The conclusion was drawn that cathepsin D and PAI-1 may play a specific role in the biology of head and neck SCC.