All malignant diseases are associated with an increased risk of thrombosis,although the incidence and presentation vary among the different types of cancer.Since Trousseau reported on the association between cancer and thrombosis,many reports have described potential mechanisms that may be involved in the pathogenesis.Malignant cells may express a number of procoagulant molecules including tissue factor (TF) and cancer procoagulant.In addition,activated or apoptotic cells liberate microparticles that mediate a procoagulant effect in linking different normal and malignant cells.Host mechanisms respond to the presence of tumor by an inflammatory and associated procoagulant reaction,essentially meant to control the growth of malignant cells.However,both tumor cell characteristics and host procoagulant response may allow tumor cells to multiply and tumors to grow and disseminate.Hence,procoagulant pathways may eventually support tumor invasion.