Abstract
Malignant cells build up a protective shield in form of a fibrin meshwork surrounding the tumor which helps it to escape the body’s immune system. In addition, tumor and stromal cells provide with an abundant extracellular matrix (ECM) consisting of proteoglycans, collagens, glycoproteins and glucosaminoglycans an additional scaffold with the capacity to bind large quantities of immunsuppressive substances. Many investigations found that heparin has a wide variety of positive effects counteracting these shielding and immunosuppressive properties of the ECM. Heparin can bind and neutralize many protective substances produced by the tumor cells. It inhibits cross-linking of collagen by deamination, and reduces the expression of FAK, LOX, glucosamines and proteoglycans. By these actions it prevents the development of a stiff and rigid ECM which presents additionally an effective scaffold for the tumor cells and also reduce the efficiency of therapeutic methods. In an ambulant trial with exogenously-added heparin in high dosages the survival probability over three years was significantly higher than without (p<0.001). Therefore, a combined therapy with a fibrinolyticum and heparin should be considered. This auxiliary treatment has the potential to support established therapy and improve anti-tumor response by the immune system.