Expression and anticoagulant function of the endothelial cell protein C receptor (EPCR) in cancer cell lines

Induction of procoagulant factors in malignant cells is considered to be th e major cause of coagulation disorders in cancer. Thrombomodulin (TM), a ne gative regulator of coagulation was also found to be expressed in cancer ce lls. We report here evidence for another anticoagulant, the endothelial cel l protein C receptor (EPCR), in cancer cells. EPCR was detected in several cell lines derived from various types of cancer. Significant levels of prot ein C (PC) activation were detected only with cell lines expressed both EPC R and TM. Anti-EPCR monoclonal antibodies (mAbs) specifically inhibited the activation. Thus. EPCR function appears to be important for PC activation by cancer cells. In addition, we detected EPCR expression in tumor cells fr om breast cancer patients, with an extremely high frequency. EPCR function may contribute to progression or pathogenesis of some types of cancer, and may explain the complexity of coagulopathy in cancer patients.