Co-localization of prothrombin fragment F1+2 and VEGF-R2-bound VEGF in human colon cancer

Background: Colon cancer (CC) is frequently complicated by thromboembolic episodes. Thrombin plays a role in angiogenesis and among others induces the synthesis of vascular endothelial growth factor (VEGF) and its receptors (VEGFR-1 and VEGFR-2). The aim of this study was to assess the expression of prothrombin fragment F1+2 (F1+2), a byproduct in thrombin generation (indicating the presence of thrombin), in relation to the presence of VEGFR-2-bound VEGF (VEGF:VEGFR-2), as an indicator of VEGFR-2 activation in human CC tissue. Materials and Methods: Immunohistochemical ABC and double staining studies were performed using antibodies against F1+2 and VEGF:VEGFR-2 in 59 specimens obtained from CC patients. Results: Medium and high expression of both F1+2 and VEGF:VEGF2 in association with CC cells and endothelial cells was demonstrated. Moreover, coexpression of F1+2 and VEGF:VEGFR-2 was observed in the cells. Conclusion: The results may suggest a possible functional interaction between thrombin and VEGF-R2 stimulation in human CC in vivo.