Changes in plasminogen activator inhibitor-1 levels in non-small cell lung cancer

Increased urokinase plasminogen activator (uPA) levels are increased in a number of malignancies and have been correlated with decreased disease-free interval and decreased overall survival. We have, therefore, examined components of this plasminogen activating system in patients with Non-Small Cell Lung Cancer (NSCLC). Levels of uPA, urokinase-plasminogen activator receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1) were measured semiquantitatively in paraffin sections of tumours from 147 patients with NSCLC. Immunohistochemically stained sections of tumour were allocated a score for stain intensity and results correlated to: survival; tumour stage(T); nodal stage(N); stage grouping (I to IIIb), survival status and sex. Increased levels of PAI-1 were associated with a decreased survival in squamous cell carcinoma (SCC) X2 = 5.72, p = 0.017 (n = 74). There was a significant positive relationship between PAI-1 levels and N-stage (p = < 0.05), presence of nodal metastases (p = < 0.05), stage grouping (p = < 0.01) and extent of disease (p = < 0.05) in the total group and the SCC subgroup, but not adenocarcinoma. There was a significant positive relationship between PAI-1 levels and T-stage (p = < 0.05) in the total group, and survival status (p = < 0.05) in the SCC subgroup alone. uPA and uPAR levels were not significantly associated with tumour staging or survival. We conclude that increased PAI-1 antigen levels may be associated with a decreased survival in patients with SCC.