An 85-amino acid recombinant peptide derived from protein c2 of the hemophagocytic hookworm Ancylostoma caninum (a common canine parasite) with anticoagulant activity. Anpocogin binds to circulating activated factor X (FXa) or zymogen factor X (FX) to form a binary complex which subsequently binds to and inhibits membrane-bound activated factor VII/tissue factor complex (FVIIa/TF). When administered prophylactically, this agent may reduce the incidence of deep venous thrombosis without hemostatic compromise. Because rNAPc2 inhibits the formation of the FVIIa/TF protease complex, which may play a role in the cellular signaling of both metastatic and angiogenic processes, it may impede tumor progression.