Tissue factor and fibrinogen (TF and Fbg)

Tissue factor (TF) and fibrinogen are two distinct but functionally linked proteins that play central roles in the human coagulation cascade. Tissue factor, also known as coagulation factor III, is a transmembrane glycoprotein that initiates the extrinsic pathway of blood coagulation upon vascular injury by forming a complex with factor VIIa [1.1.1, 1.1.3]. Fibrinogen, or coagulation factor I, is a large, soluble plasma glycoprotein that serves as the final substrate in the cascade, where it is converted by thrombin into insoluble fibrin to form the structural matrix of a blood clot [1.2.1, 1.2.3]. Beyond hemostasis, both proteins are involved in inflammation, angiogenesis, and tumor progression [1.1.2, 1.2.4]. Tissue factor is frequently overexpressed in various cancers and is the target of the antibody-drug conjugate tisotumab vedotin [1.3.2]. Fibrinogen is therapeutically managed through supplementation with concentrates in cases of deficiency or through depletion by defibrinogenating agents in certain thrombotic conditions [1.2.1, 1.3.4]. The dysregulation of these factors is a hallmark of diseases such as deep vein thrombosis, pulmonary embolism, and disseminated intravascular coagulation [1.1.3, 1.2.4].

Other names

Coagulation factor III and Coagulation factor IThromboplastin and FibrinogenTF and Fbg

Tissue factor initiates the extrinsic coagulation pathway by forming a complex with Factor VIIa, while fibrinogen is the final substrate converted into fibrin by thrombin to form a blood clot. Drugs targeting these molecules either inhibit the initiation of coagulation (TF inhibitors) or modulate the final clot formation (fibrinogen supplementation or depletion).