Postsurgical thrombosis represents a serious comorbidity in bladder cancer. Inflammation and hemostatic activation mediators contribute to thrombotic pathogenesis. This study profiled such biomarkers as antiphospholipid antibody, IgG subtype (APA), procoagulant microparticles (MP) and antiglycosaminoglycan antibody (AGA). Thrombin generation profile was also carried out. In addition protein and peptide biomarkers were profiled using SELDI-TOF mass spectrometry.
This study was conducted retrospectively using an IRB approved protocol with 134 baseline serum samples collected from patients undergoing radical cystectomy. The samples were banked at −70C and thawed prior to analysis. The normal group was comprised of plasma samples collected from healthy male and female individuals (n=50). The APA were measured with an ELISA for IgG specific antibodies (American diagnostica, Stanford CT). The MP were measured using an anexin capture chromogenic substrate to quantify functional procoagulant activities (Hyphen Biomedical, Paris France). The AGA were measured with a commercially available method with a polysulfonate polymer capture probe for the antibodies (GTI Madison, WI). Thrombin generation studies were carried out by using a fluormetric method (Technoclone). The proteomic profile was analyzed on a GoldChip in the range of 5–150 kDa.
In comparison to the normal group, a wide scatter in the cancer group was noted, all of these exhibited a higher prevalence of elevated biomarkers compared to normal. The average MP value was 3.1+5.8nM (range 0.1–34.6nM) with 26 of 134 samples above the normal values which are (2.8+1.1). The average APA value was 6.7+11 (range 4–65nM) with 32 above normal. The average AGA value was 0.22+0.09 (range .01-.8OD) with 10 above normal. The SELDI analysis showed unique biomarkers in the area of 11–12kDa, 15.1–15.4kDa, and 15.8–16.2kDa which were absent in the normal group. The serum samples showed the presence of higher amidolytic activities for serine proteases. The thrombin generation studies in a modified method also showed a higher thrombin generation in the cancer group.
The biomarker upregulation suggests that bladder cancer patients have subclinical activation of thrombotic and inflammatory processes. The MP may be generated in cellular damage whereas the APA and AGA suggest vascular endothelial damage and activation. The unique proteomic biomarkers in these patients suggest endogenous protease activation. The increased protease activity and higher thrombin generation suggest a role of microparticles in mediating thrombogenesis. A clinical correlation in the subset with higher markers may provide insight into the biomarker role in prognosis, risk stratification and treatment of bladder cancer.
No relevant conflicts of interest to declare.
Asterisk with author names denotes non-ASH members.