Platelet and coagulation activation with vascular endothelial growth factor generation in soft tissue sarcomas

Angiogenesis and activated blood coagulation are involved in tumor growth a nd metastasis. Although some have suggested that activation of coagulation in tumors is not linked to activation of platelets, no data exist to either support or refute this concept, However, platelet turnover in cancer patie nts is often increased, and platelets are carriers of angiogenic growth fac tors. We hypothesized that platelets are involved in tumor-associated angio genesis. To obtain evidence supporting this hypothesis, we have studied whe ther the angiogenic and coagulation pathways and platelets are concomitantl y activated in cancer patients with soft tissue sarcomas (STSs) using a nov el method to detect activated platelets in tumor specimens. Twelve patients with STS were selected on the basis of having intratumoral accumulation of fluid, which was aspirated. These accumulations demonstrated very high con centrations of vascular endothelial growth factor and coagulation factors ( including thrombin-antithrombin-complex), Tumor specimens showed dense vasc ularization with intense vascular endothelial growth factor expression and the presence of activated platelets, Taken together, these results support the concept that angiogenesis, blood coagulation, and platelets are concomi tantly activated in STS and support the hypothesis that platelets contribut e to tumor-induced angiogenesis.