Original Paper Pathophysiol Haemost Thromb 2002;32:2–7 Pathophysiology and Thrombosis of Haemostasis Resistance to Activated Protein C, Factor V Leiden and the Prothrombin G20210A Variant in Patients with Colorectal Cancer Gregorios A. Paspatis a Aikaterini Sfyridaki b Nikolaos Papanikolaou a Kostantinos Triantafyllou a Aikaterini Livadiotaki b Andreas Kapsoritakis a Niki Lydataki a a Department of Gastroenterology and b Regional Blood Bank Center, Benizelion General Hospital, Heraklion, Greece Received: December 8, 2000 Accepted in revised form: August 20, 2001 G.A. Paspatis, MD G. Georgiadou 17 Heraklion 71305, Crete (Greece) Tel. +30 81 288271, Fax +30 81 281225 E-Mail paspati@lyttos.admin.teiher.gr ABC Fax + 41 61 306 12 34 E-Mail karger@karger.ch www.karger.com © 2002 S. Karger AG, Basel 1424–8832/02/0321–0002$18.50/0 Accessible online at: www.karger.com/journals/pht Key Words Activated protein C W Factor V Leiden W Prothrombin G20210A variant W Colorectal cancer W Greece Abstract Objective: The aim of our study was to determine the frequency of resistance to activated protein C (APC), fac- tor V Leiden (FVL) and the prothrombin G20210A variant in patients with colorectal cancer. M ethods: 74 patients with colorectal cancer and 192 colonoscopically selected controls were prospectively investigated for the pres- ence of APC resistance, FVL and the prothrombin G20210A variant. APC resistance was measured as the ratio of activated partial thromboplastin times with and without APC (APC sensitivity ratio, APC-SR). The FVL and prothrombin G20210A variant were detected by a poly- merase-chain-reaction-based technique. Results: FVL was detected in the heterozygous form in 4 of 74 cancer patients (5.4%) and in 7 of 192 controls (3.6%; p 1 0.5, odds ratio: 1.51). After excluding patients and controls with FVL, APC-SR was below 2 in 6 of 70 cancer patients (8.5%) and in 1 of 185 controls (0.5%; p ! 0.01, odds ratio: 17.25), and the mean value of APC-SR was significantly lower in cancer patients than the respective level of con- trols (2.8 vs. 3.7, p ! 0.001). The G20210A mutation in the prothrombin gene was found in the heterozygous form in 2 of 74 patients with colorectal cancer (2.7%) and in 5 of 192 colonoscopically control subjects (2.6%; p 1 0.5, odds ratio: 1.03). Conclusions: These findings suggest that patients with colorectal cancer have a high frequen- cy of resistance to APC but no significant differences in the frequency of the FVL or G20210A mutation of the pro- thrombin gene compared to colonoscopically selected controls. Copyright © 2002 S. Karger AG, Basel Introduction Thromboembolic episodes are a major complication in patients undergoing surgery. Moreover, patients undergo- ing colorectal surgery are at a significantly higher risk for the development of thromboembolic episodes than most other patients undergoing a general surgical procedure [1]. It has been reported that both coagulation and fibrinolysis