Urokinase-type plasminogen activator and its inhibitor plasminogen activator inhibitor-1: New functional risk factors in head and neck squamous cell cancer

Tumor associated proteolysis is an essential mechanism in invasion and metastasis of cancer. The influence of the serine protease urokinase-like plasminogen activator (u-PA) and its inhibitor plasminogen activator inhibitor-1 (PAI-1) on the clinical prognosis of squamous carcinoma of the head and neck region (HNSCC) was evaluated. U-PA and PAI-1 levels were measured in tumor biopsies of 41 HNSCC patients and 6 biopsies of healthy oral mucosa using ELISA technique. Patients were followed for an average of 24 months. U-PA concentration in tumor tissue was four times higher than in healthy mucosa (4.96 ng/mg protein versus 1.32 ng/mg). PAI-1 levels were 22 times higher (69.55 ng/mg versus 3.18 ng/mg). Univariate Cox regression analysis revealed significant correlation (p=0.022) of PAI-1 with recurrence of the disease and no significance for u-PA. PAI-1 might become a new functional risk factor reflecting clinical prognosis.