RESUMEN
BACKGROUND/AIMS: Urokinase (uPA) is a serine protease, which together with uPAR, tPA, PAI 1 and PAI 2 forms the plasminogen activator system, a component of metastatic cascade contributing to the invasive growth and angiogenesis of malignant tumours. METHODOLOGY: Both preceding therapy and after 6-8 weeks of the treatment, plasma PAI 1 levels (photometric microplate method on the ELISA) and uPA, uPAR, PAI 1 and PAI 2 tissue expression (immunohistochemical reaction) were analysed from 80 colorectal carcinoma patients. RESULTS: Analysis showed higher pre-treatment plasma levels of PAI 1 in patients with advanced tumours, which decreased after surgery or the start of therapy (p=0.004); Patients with higher plasma level PAI 1 before (0.013) and after therapy (0.004) had significantly shorter survival. There was a higher expression of uPA (p<0.001), uPAR (p<0.001), PAI 1 (p=0.042) and PAI 2 (p<0.001) in advanced colorectal carcinoma. A relationship between PAI 2 (p=0.010) and uPAR (p=0.019) expression and survival was demonstrated. There is a correlation between pre-treatment plasma PAI 1 levels and PAI 2 (p=0.028) and uPAR (p=0.043) expression. CONCLUSIONS: Immunohistochemical analysis of PAS in tumour tissue and plasma PAI 1 levels was found to be a useful prognostic factor in colorectal carcinoma patients. Plasma PAI 1 could be advantageous in evaluating the effectiveness of a mode of treatment.