Tissue factor-positive microparticles: Cellular origin and association with coagulation activation in patients with colorectal cancer

The pathogenesis of hypercoagulability in cancer is not entirely understood. We hypothesized that in cancer patients circulating tissue factor-positive microparticles (TF+ MPs) are increased and associated with hemostatic system activation. In 20 patients with advanced colorectal cancer and in 20 age- and sex-matched controls, number and cellular origin of TF+ MPs were determined in plasma by flow cytometry. D-dimer was determined as an indicator of hemostatic system activation. Compared to controls, the median (interquartile range) number of TF+ MPs was two-fold higher in cancer patients: 25.9 (15.4 - 42.0) x 10(3)/ml plasma versus 13.1 (11.9 - 19.7) x 10(3)/ml plasma, p = 0.007. This was mainly due to a higher amount of TF+ MPs from platelets (13.4 [5.0 - 17.4] x 10(3)/ml plasma vs. 5.8 [4.5 - 7.5] x 10(3)/ml plasma, p = 0.017). TF+ MPs correlated with D-dimer (p = 0.48, p = 0.002). High levels of TF+ MPs in cancer patients and their correlation with D-climer suggest that TF+ MPs might be involved in hemostasis activation in cancer patients.