title: Acquired resistance to activated protein C in breast cancer patients.
abstract: In 56 women with a lymph-node-positive breast carcinoma and 28 matched healthy control subjects, the sensitivity to activated protein C (APC-sr) was determined with an APC resistance test that quantifies the effect of APC on thrombin generation initiated via the extrinsic coagulation pathway. Carriers of the Factor V Leiden mutation were excluded from the study. Significant resistance to APC was found in the breast cancer patients: median APC-sr 2.02 vs 1.03 in the healthy control subjects (P < 0.001). No difference in APC-sr was found between patients with metastases and without metastases. In patients with metastases, protein S levels were significantly elevated compared with patients without metastases and healthy control subjects: 108.0%vs 96.0% and 94.5% (P = 0.008 and P = 0.007). The APC-sr correlated with protein S in the control subjects and in patients without metastases but not in patients with metastases. The disturbance of the haemostatic balance probed by the tissue-factor-based APC resistance test might contribute to the cancer-related hypercoagulability.
authors.affiliation: Department of Haematology, University Hospital Maastricht, The Netherlands. mnijz@sint.azm.nl
authors.forename: Marten R
authors.initials: MR
authors.lastname: Nijziel
authors.forename: Rene
authors.initials: R
authors.lastname: van Oerle
authors.forename: M
authors.initials: M
authors.lastname: Christella
authors.forename: L G D
authors.initials: LG
authors.lastname: Thomassen
authors.forename: Elisabeth C M
authors.initials: EC
authors.lastname: van Pampus
authors.forename: Karly
authors.initials: K
authors.lastname: Hamulyák
authors.forename: Guido
authors.initials: G
authors.lastname: Tans
authors.forename: Jan
authors.initials: J
authors.lastname: Rosing
mesh_terms: D020016:Activated Protein C Resistance / Q000097:blood / Q000150:complications*; D000368:Aged; D000991:Antithrombins / Q000032:analysis; D001780:Blood Coagulation Tests; D001943:Breast Neoplasms / Q000097:blood* / Q000556:secondary*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008875:Middle Aged; D017293:Protein S / Q000032:analysis; D018709:Statistics, Nonparametric
chemical_list: D000991:Antithrombins; D017293:Protein S