Disclosed are compositions, kits, and methods for treating and/or diagnosing cancer in a subject in need thereof. The compositions, kits, and methods may be used to treat and/or diagnose cancers associated with BST-2 expression and/or BST-2 biological activity. Also disclosed are reagents that inhibit dimerization of BST-2 which may be administered as therapeutic agents for inhibiting BST-2 biological activity and treating cancers associated with BST-2 biological activity.
