Tissue factor
（重定向自Coagulation factor III）
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![The coagulation cascade.](/Images/godic/202501/05/Coagulation_full.svg2508.png")
![](/Images/godic/202501/05/PDB_1ahw_EBI2508.jpg")
Tissue factor, also called platelet tissue factor, factor III, thromboplastin, or CD142 is a protein present in subendothelial tissue and leukocytes necessary for the initiation of thrombin formation from the zymogen prothrombin. Thromboplastin defines the cascade that leads to the activation of factor X - the tissue factor pathway. In doing so it has replaced the previously named extrinsic pathway in order to eliminate ambiguity.