The invention provides a method for preventing or treating a disorder mediated by a Slit protein which comprises administering to a subject a therapeutically effective amount of an agent for modulating or preventing interactions between the Slit protein and a Robo protein wherein the disorder involves lymph vessel formation. The invention further discloses a composition for preventing or treating a disorder mediated by the Slit protein and a method for prognosing or diagnosing a disease or disorder mediated by the Slit protein.
