Markers of Coagulation and Angiogenesis Can Serve As Surrogate Biomarkers for Disease Activity and Survival in Cancer Patients

Based on observations of the link between hemostatic system and malignancy it is plausible to consider that plasma coagulation factors could serve as easily accessible markers for detection of malignant state and monitoring of cancer patients. Therefore, we hypothesized that tissue factor (TF), angiopoietin-2 (Ang-2) and soluble urokinase plasminogen activator receptor (suPAR) might perform as diagnostic and predictive biomarkers for the presence of malignancy as well as for the development of cancer-related events: metastatic progression and death.

To analyze their performance TF-associated microparticle activity (MPTF), tissue factor antigen (TFAg), Ang-2 and suPAR were determined in 128 cancer patients with various cancer types receiving chemotherapy by sequential measurements (up to four times) at prespecified time points incorporated into interim and end-of-treatment analysis. MPTF activity was measured with Zymuphen MPTF kit, TFAg, suPAR and ANG-2 were quantitated by ELISA. Patients were followed up for progression free survival (PFS) from therapy initiation until occurrence of a combined event defined as either metastatic progression or death. In order to determine the predictive ability of hemostatic biomarkers for a PFS event Log-rank (Mantel-Cox) test was applied. ROC analysis was used to determine the cut off values for detection of an event, cut off values were transformed into binary variables and Kaplan-Meier curves were constructed. Cox regression analysis was applied to explore quantitatively the effect on the risk of progression.

Results: Cut off values for the occurrence of an event were MPTF < 0.5 pg/ml (AUC 0.591), TFAg (√ pg/ml) > 8.28 (AUC 0.603), Ang-2 > 302.3 pg/ml (AUC 0.615) and suPAR (√ pg/ml) > 2.83. Shortened PFS was associated with decreased MPTF procoagulant activity and elevated plasma levels of TFAg, Ang-2, suPAR. As significant predictors for PFS were determined only TFAg (RR 4.57, p=0.038), Ang-2 (RR 2.138, p=0.031) and suPAR (RR 2.238, p=0.049).

Conclusion: TFAg, Ang-2 and suPAR might be identified as significant adverse predictors of metastatic progression or death in cancer patients and risk is increased with elevated plasma levels.