The present invention relates to methods and pharmaceutical compositions for the prophylactic treatment of metastases. The inventors showed in vivo that lung metastasis in GPVI deficient mice are reduced compared to controls. They demonstrated that GPVI is involved in platetet interaction with tumor cells and this interaction is mediated by EMMPRIN.). Using an anti-EMMPRIN antibody, they showed that the adhesion of platelets to tumors cells is decreased. In particular, the present invention relates to a method for the prophylactic treatment of metastases in a patient suffering from cancer comprising administering to the subject a therapeutically effective amount of an agent which inhibits the interaction between GPVI and EMMPRIN.