[The prognostic importance of urinase type plasminogen activators (uPA) and plasminogen activator inhibitors (PAI-1) in the primary resection of oral squamous cell carcinoma]

Abstract

This article examines the prognostic importance of urinase type plasminogen activators (uPA) and of plasminogen activator inhibitors (PAI-1) in cases of primary oral squamous cell carcinoma. Tissue samples were taken from the core of the tumour in 58 such primary surgical patients. The levels of uPA and PAI-1 were determined using ELISA. Statistical significance was calculated using the chi2- and log-rank tests. The mean follow-up (n=58) was 23 months. In order to determine prognostic value, the time before relapse was used. The mean time before relapse was 19 months. A total of 28 (40%) patients relapsed (local n=13, lymph node n=3, local and lymph node n=1, lymph node and skin n=1, other locations n=5). Such patients had significantly raised uPA (P<0.012) and PAI-1 (P<0.014) levels in the primary tumour. A optimal cutoff value for uPA (4.58 ng/mg) and PAI-1 (106.3 ng/mg) was determined using the multiple log-rank test. There was no significant correlation for patients with low or high levels (i.e. lower or higher than the cutoff value, respectively) with the usual clinical parameters such as localisation, N-stage, T-stage, differentiation and residual tumor status. Older patients (>58 years) had significantly higher levels of uPA and PAI-1 (P<0.017 and P<0.02, respectively). The likelihood of relapse was significantly higher in patients with high levels (uPA P<0.009, PAI-1 P<0.008). If the patients were divided into three groups depending on uPA and PAI-1 levels (group 1: uPA and PAI-1 low, n=35; group 2: uPA or PAI-1 high, n=12; group 3: uPA and PAI-1 high, n=11), relapses were more common in group 3 than in groups 1 or 2 (P<0.023). Patients with only surgical therapy (n=29) and those with postoperative radiotherapy (n=29) were used to evaluate postoperative follow-up. Cutoff levels were calculated for both groups. In the surgical therapy group this was uPA=5.63 ng/mg and PAI-1=106.3 ng/ml and in the surgical therapy plus radiotherapy group uPA=4.13 ng/mg and PAI-1=97.02 ng/mg. Kaplan-Meier curves showed a marked tendency for patients with higher levels to relapse more often. This is significant for surgical patients for PAI-1 (P<0.01) and for radiotherapy patients for uPA (P<0.04)