Factor V Leiden, prothrombin 20210A and the risk of venous thrombosis among cancer patients

Summary Cancer patients have an increased risk of venous thrombosis (VT). The association of factor V Leiden (FVL) and the prothrombin 20210A variant with VT in cancer patients is not established. We genotyped 101 cancer patients with VT and 101 cancer patients without VT for these polymorphisms. Five cases and three controls were heterozygous for FVL, yielding an odds ratio of 1·7 (95% confidence interval (CI) 0·3–10·7). Five cases and no controls were heterozygous for prothrombin 20210A, for an odds ratio of 6·7 (95% CI 0·9–infinity). Prothrombin 20210A may be associated with VT risk among cancer patients.