Abstract: In one aspect, the invention relates to an inhibitor of the ?6 integrin/E-cadherin molecular complex for use as a medicament, in particular for the prevention or/and treatment of metastases of a primary cancer disease and a pharmaceutical composition or kit comprising as an active agent at least one of the inhibitors. In a further embodiment, the present invention relates to a method for determining the prognosis of metastatic homing of a primary cancer disease, in particular the aggressiveness of the metastatic potential of a primary cancer disease.