The present invention relates to a method for identifying inhibitors of breast cancer metastasis based on a screening with proteins that are specific for the secretome of a chondrocyte, preferably cytokines and/or chemokines. The ligands as identified lead to a decrease of the migration and/or a re-differentiation of a breast cancer cell and/or a reduction of the number and/or size of breast cancer metastases. The present invention further relates to a method for detecting breast cancer metastasis, comprising the step of detecting at least one protein that is specific for the secretome of a chondrocyte, and for methods for treating and/or preventing breast cancer metastasis in a patient in need thereof, comprising the step of administering an effective amount of at least one ligand for one protein that is specific for the secretome of a chondrocyte to said patient in need thereof.
