Prothrombotic genotypes and risk of venous thromboembolism in cancer.

Venous thromboembolism (VTE) is a common and potentially life-threatening complication in cancer. Patients with cancer are at a higher risk of VTE-related complications such as major bleeding during anticoagulant treatment, recurrence and mortality. Therefore, it is important to identify cancer patients with high risk of VTE in order to implement targeted prevention to those with a favorable benefit-to-harm ratio for thromboprophylaxis. VTE is strongly heritable, and during the last decades, several prothrombotic genotypes associated with VTE-risk have been identified. However, most of these studies were conducted in non-cancer patients, and the role of prothrombotic genotypes in cancer-related VTE is scarcely studied. In this review, we summarize current knowledge on the role of prothrombotic genotypes in cancer-related VTE, with particular focus on factor V Leiden, the prothrombin G20210A mutation and polymorphisms in the ABO gene. In general, many of the studies were small and performed in selected cancer populations, and they showed somewhat diverging results. Results from recent, larger, studies indicated that there is an association between these prothrombotic genotypes and cancer-related VTE. However, their predictive capability has not been assessed and the clinical implications are yet unclear. Future research should be conducted in larger cancer patient populations, and should be extended to include recently identified prothrombotic genotypes and assess the predictive value of genetic risk scores.