Preoperative plasma soluble urokinase plasminogen activator receptor as a prognostic marker in rectal cancer patients. An EORTC-Receptor and Biomarker Group collaboration.

BACKGROUND AND AIMS: Since approximately 30% of patients with Dukes' stage B colorectal cancer will experience disease recurrence within five years of primary treatment, current staging of patients with early colorectal cancer apparently fails to adequately predict patient outcome. It has previously been shown that the preoperative plasma concentration of soluble urokinase plasminogen activator receptor (suPAR) is associated with the survival of patients with early colorectal cancer. In this study we sought to confirm the independent prognostic value of suPAR in rectal cancer. METHODS: suPAR was retrospectively determined by two different versions of a suPAR ELISA in preoperatively collected plasma samples from a Swedish (n = 354) and a Danish (n = 255) cohort of rectal cancer patients. RESULTS: In both cohorts the suPAR concentration was significantly higher in Dukes' stage D patients than in Dukes' stage A-C patients (p < 0.0001). Among Dukes' stage A-C patients, no differences in median suPAR values were seen. In univariate analysis, continuous suPAR was found to be associated with survival (p < 0.0001 in both cohorts). Of particular interest was that similar results were obtained for Dukes' stage A and B patients when analyzed separately. In multivariate analysis, continuous suPAR was found in both cohorts to be independent of Dukes' stage. CONCLUSIONS: This study confirms that the preoperative concentration of plasma suPAR contains independent prognostic information on patients with rectal cancer. This result was independent of the two different versions of an in-house suPAR ELISA used to perform the analyses. The next step in the evaluation of suPAR as a prognostic parameter in rectal cancer will be to launch an appropriately dimensioned prospective study where the benefit of applying preoperative plasma suPAR measurement to clinical decision-making regarding adjuvant therapy is assessed.

Measurement of plasminogen activator system components in plasma and tumor tissue extracts obtained from patients with breast cancer: an EORTC Receptor and Biomarker Group collaboration.

The plasminogen activator (PA) system comprises the 2 serine proteases, urokinase PA (uPA) and tissue PA (tPA), the 2 serpin inhibitors, PAI-1 and PAI-2 and the uPA receptor (uPAR; CD87). High levels of uPA, PAI-1, uPA-PAI-1 complex and uPAR in breast cancer tissue are associated with poor prognosis, while high levels of tPA or PAI-2 correlate with good prognosis. In this study, pre-operative plasma levels of uPA, PAI-1, uPAR, tPA, uPA-PAI-1 complex, and tPA-PAI-1 complex were measured in patients with benign (n=103) and malignant breast disease (n=113) by immunoenzymatic assays (ELISA). While plasma antigen levels of uPA, PAI-1, uPA-PAI-1 complex and uPAR were not significantly different in the 2 groups, antigen levels of tPA and tPA-PAI-1 complex were significantly higher in patients with breast carcinoma compared to the control group. In plasma from the breast cancer patients, uPA levels correlated weakly but significantly with those of tPA (r=0.20, p=0.035) and uPAR (r=0.208, p=0.028). tPA levels correlated strongly with tPA-PAI-1 complex (r=0.972, p=0.0001) while uPA-PAI-1 levels were significantly associated with PAI-1 levels (r=0.534, p<0.0001), tPA levels (r=0.348, p=0.0003) and tPA-PAI-1 levels (r=0.356, p=0.002). However, no significant correlation was found between plasma and tumor tissue levels of uPA, PAI-1, uPA-PAI-1 complex, tPA or tPA-PAI-1. Our findings indicate that determination of these factors in plasma do not reflect their concentration in tumor tissue. Therefore, measurement of PA components in blood cannot be recommended for assessing prognosis in breast cancer.

Preoperative plasma soluble urokinase plasminogen activator receptor as a prognostic marker in rectal cancer patients. An EORTC-Receptor and Biomarker Group collaboration.

BACKGROUND AND AIMS: Since approximately 30% of patients with Dukes stage B colorectal cancer will experience disease recurrence within five years of primary treatment, current staging of patients with early colorectal cancer apparently fails to adequately predict patient outcome. It has previously been shown that the preoperative plasma concentration of soluble urokinase plasminogen activator receptor (suPAR) is associated with the survival of patients with early colo-rectal cancer. In this study we sought to confirm the independent prognostic value of suPAR in rectal cancer. METHODS: suPAR was retrospectively determined by two different versions of a suPAR ELISA in preoperatively collected plasma samples from a Swedish (n=354) and a Danish (n=255) cohort of rectal cancer patients. RESULTS: In both cohorts the suPAR concentration was significantly higher in Dukes stage D patients than in Dukes stage A-C patients (p<0.0001). Among Dukes stage A-C patients, no differences in median suPAR values were seen. In univariate analysis, continuous suPAR was found to be associated with survival (p<0.0001 in both cohorts). Of particular interest was that similar results were obtained for Dukes stage A and B patients when analyzed separately. In multivariate analysis, continuous suPAR was found in both cohorts to be independent of Dukes stage. CONCLUSIONS: This study confirms that the preoperative concentration of plasma suPAR contains independent prognostic information on patients with rectal cancer. This result was independent of the two different versions of an in-house suPAR ELISA used to perform the analyses. The next step in the evaluation of suPAR as a prognostic parameter in rectal cancer will be to launch an appropriately dimensioned prospective study where the benefit of applying preoperative plasma suPAR measurement to clinical decision-making regarding adjuvant therapy is assessed. (Int J Biol Markers 2005; 20: 93-102).

Soluble urokinase plasminogen activator receptor in blood transfusion components.

Post-transfusion infectious complications associated with allogeneic blood components may depend on storage time and may be related to extracellular accumulation of bioactive substances during storage. The glycoprotein, soluble urokinase plasminogen activator receptor (suPAR), which is located in specific granules of neutrophils, plays a role in inflammation and remodelling of the extracellular matrix. Using enzyme-linked immunosorbent assay, suPAR was determined in serum, plasma and blood cell lysates. In addition, suPAR was measured in whole blood (WB), buffy-coat-depleted saline-adenine-glucose-mannitol (SAGM) blood, platelet-rich plasma (PRP) and buffy-coat-derived platelet (BCP) pools with and without pre-storage leucofiltration, and in non-filtered WB, SAGM blood and platelet concentrates prepared using apheresis (APC) at different time points during storage. Mean suPAR concentration was significantly higher in cell lysates, compared to that in a corresponding serum (P = 0.007) and in plasma samples (P = 0.004). Mean suPAR levels in WB, BCP and SAGM were significantly reduced using leucofiltration (WB: 3.4 versus 2.0 ng mL(-1); BCP: 1.6 versus 1.1 ng mL(-1); SAGM: 2.8 versus 0.19 ng mL(-1)), whereas no difference was observed in PRP. In non-filtered WB, SAGM and APC, extracellular suPAR accumulated significantly in a storage-time-dependent manner (WB: P < 0.01; SAGM: P < 0.001; APC: P < 0.001). The present study demonstrates that cell lysates contain significantly more suPAR, compared to both serum and plasma. This can be explained by the release of suPAR from intracellular granules during cell lysis. The amount of suPAR is significantly increased during storage of blood transfusion components, an accumulation that is reduced using pre-storage leucofiltration.

Soluble urokinase plasminogen activator receptor in preoperatively obtained plasma from patients with gynecological cancer or benign gynecological diseases.

OBJECTIVE: The present study was planned to measure preoperative levels of soluble urokinase plasminogen activator receptor (suPAR) in plasma from patients with gynecological diseases, and to test for a relationship to clinical and biochemical patient characteristics. METHODS: Using a specific and sensitive kinetic ELISA, suPAR levels were determined in preoperative citrate plasma samples from 53 ovarian, 34 endometrial, and 30 cervical cancer patients, 17 patients with benign ovarian tumors, and 28 patients with benign endometrial diseases. In addition, suPAR was measured in citrate samples from 31 female blood donors. RESULTS: suPAR was measurable in all samples. No significant difference was found between plasma suPAR in the blood donors and the patients with benign diseases (P = 0.58). The groups of cancer patients had suPAR levels that were significantly higher than those found in the blood donors (P < 0.0001, P < 0.0001, and P = 0.001 for patients with ovarian, endometrial, and cervical cancer, respectively). In all groups of cancer patients a trend toward increasing suPAR levels with increasing FIGO stage was noted (P = 0.0003, P = 0.02, and P = 0.01 for patients with ovarian, endometrial, and cervical cancer, respectively). Using the median suPAR level to dichotomize the ovarian cancer patients, FIGO stages I-III, a significantly increased risk of progression/relapse was found for patients with high suPAR levels (Hazard ratio (HR) = 3.1, 95% CI: 1.1-8.8, P = 0.03). A multivariate analysis was performed, including suPAR, FIGO stage, and CA-125. Only FIGO stage III compared with FIGO stage I was significant (HR = 15, 95% CI: 1.8-129, P = 0.01). Survival analyses were not performed in the endometrial or cervical cancer patients due to few progressions/relapses during the follow-up period. CONCLUSION: This study concludes that patients with gynecological cancers have elevated plasma suPAR levels as compared with healthy female blood donors and patients with benign gynecological diseases. In addition, high preoperative plasma levels of suPAR are significantly associated with poor outcome of ovarian cancer patients. However, additional studies are needed to further validate the clinical usefulness of plasma suPAR measurements in the management of ovarian cancer patients.

Soluble urokinase plasminogen activator receptor measurements: influence of sample handling.

AIM: The influence of sample handling on soluble urokinase plasminogen activator receptor (suPAR) concentrations in serum and EDTA plasma was studied in 16 healthy premenopausal women. METHOD: Blood was collected in dry tubes and tubes containing EDTA and kept at 4 degrees C or 20 degrees C for 1, 3, 8, 24 or 72 hours before processing into serum or EDTA plasma. In addition, serum and EDTA plasma were frozen and thawed 1-8 times. All suPAR measurements were performed by ELISA. RESULTS: No significant differences were found between serum or EDTA plasma suPAR concentrations when whole blood samples were kept for 1, 3, 8 or 24 hours. Significantly higher suPAR levels were found in samples kept for 72 hours at 20 degrees C compared to samples processed into serum or EDTA plasma after short-term storage for no more than 24 hours after collection. No significant differences were observed when whole blood was kept at 4 degrees C for up to 72 hours. Repeated freezing and thawing had no significant effect on the serum and EDTA plasma suPAR levels. CONCLUSION: suPAR values in blood samples are dependent on the handling procedures of the samples. All samples of whole blood must be processed into EDTA plasma or serum within 24 hours if kept at 20 degrees C and within 72 hours if kept at 4 degrees C. However, repeated freezing/thawing cycles had no influence on suPAR values in the samples.