The occurrence of six variants was analyzed in approximately 1,800 colorectal cancer patients and in the same number of healthy control persons.

Scientists at the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ; Heidelberg, Germany) headed by Prof. Dr. Hermann Brenner studied the six gene variants of different clotting factors for a possible connection with colorectal cancer risk.

The team found a variant that substantially increases the risk of thrombosis, which is known as factor V Leiden (FVL). Study participants who carry this genetic variant on both copies of their chromosome 1 were found to have a six-fold increase in colorectal cancer risk compared to participants who carry two copies of the "standard variant" of factor V. If only one copy of chromosome 1 had the FVL variant, bowel cancer risk was not elevated.

Another connection with bowel cancer prevalence was found by the team for a particular gene variant of clotting factor XIII: people with this mutation are more slightly less affected by venous thrombosis than those who carry the factor XIII standard version. The DKFZ team showed that their colorectal cancer risk is also 15% lower. For the other four gene variants studied, the team found no connection with bowel cancer risk.

The knowledge of these connections is the first prerequisite for finding out whether and for whom drugs that affect blood clotting may prevent bowel cancer.

It is known that coagulation and carcinogenesis are associated. Thus, the interplay of all coagulation factors leads to the formation of active thrombin, which, in turn, activates hemostatic fibrin. However, thrombin also contributes to the formation of new blood vessels and is able to dissolve the extracellular matrix, which is the adhesive that keeps cells together. Thrombin may thus make it easier for cancer cells to invade surrounding tissue.

The study appeared ahead of print in the March 2011 edition of the Journal of Clinical Oncology.

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German Cancer Research Center