The prognostic value of plasma soluble urokinase plasminogen activator receptor (suPAR) levels in stage III ovarian cancer patients

The level of the urokinase plasminogen activator receptor (uPAR) is elevated in tumor tissue from several forms of cancer. uPAR is shed from the cell surface and the soluble form, soluble urokinase plasminogen activator receptor (suPAR), has been detected in several body fluids. High plasma levels of suPAR in patients with colorectal cancer and high serum levels of suPAR in patients with recurrent metastatic breast cancer have been associated with poor prognosis. In patients with ovarian cancer (OC) it has been shown that the level of suPAR is very high in ascites and cystic fluid and that high serum levels of suPAR were associated with shorter survival of the patients. We evaluated suPAR preoperatively in plasma from primary OC stage III patients and tested for association with prognosis. The prognostic significance of suPAR was also compared to two biochemical markers; cancer antigen 125 (CA125) and tetranectin (TN). No significant differences were found between patients who died of OC compared to patients still alive regarding median plasma suPAR levels (p=0.62) and median serum CA125 levels (p=0.26). In contrast, a significant difference was found between dead and alive OC patients for the median serum TN level (p<0.0001). Dividing the patients into two groups, corresponding to preoperative plasma suPAR levels below or equal to 2.0 ng/ml and higher than 2.0 ng/ml, no significant difference in survival was found between the two groups (p=0.49). When different cut-off levels of plasma suPAR were considered (2.74 ng/ml, 3.25 ng/ml and 4.18 ng/ml), no significant differences in survival could be detected (p=0.58, p=0.68 and p=0.05). Multivariate Cox regression analysis showed that the only independent prognostic factors were radicality after primary surgery (RH=5.34; 95% CI, 2.34-12.20; p<0.0001) and preoperative serum TN (RH=0.69, 95% CI, 0.57-0.82; p<0.0001), whereas plasma suPAR (4.18 ng/ml), age, histological type of tumour and serum CA 125 had no independent prognostic value. In conclusion, preoperative plasma suPAR level was of no prognostic value in this cohort of Danish stage III OC patients.