Tissue Factor and Breast Cancer

Tissue Factor (TF), a membrane bound glycoprotein, is the cellular initiator of the protease blood coagulation cascade. TF is a component of tissue factor/factor VII (TF/FVII) complex which plays key roles in extrinsic coagulation pathway. According to the traditional view of blood coagulation, although the initial phase of coagulation is triggered by the extrinsic pathway, the amplification of the coagulation cascade is triggered by the intrinsic pathway. Emerging experimental evidences show a broad range of biological functions of TF including hemostasis, thrombosis, hypercoagulability etc. In addition to the role of TF as an initiator of coagulation cascade, TF is also involved in many cancer-related processes like tumor growth, angiogenesis, metastasis etc. It is now widely recognized that a strong correlation exists between TF expression and breast cancer and plasma TF concentration has been found to be up-regulated in primary and recurrent breast cancer patients. TF-induced thrombin can activate several members of the protease activated receptor (PAR) family. Expression of protease activated receptor 1 (PAR1) is both required and sufficient to promote growth and invasion of breast carcinoma cells. Like PAR1, protease activated receptor 2 (PAR2) has also been found to play a critical role in breast cancer cell migration and invasion. Thus, TF plays a very crucial role in breast cancer progression. This review focuses on the role of TF in breast cancer progression based on the evidences available. Better understanding the role of TF in breast cancer will provide considerable clinical benefits associated with breast cancer treatment.