The present invention is directed to improved compositions for the disruption of signaling through the external domain (ED) of MUC1, Ligand traps—molecules that include MUC1 ED sequences and immunoglobulin Fc domains—effectively “trap” molecules that interact with the native MUC1 ED. Given the involvement of MUC1 in a variety of disease states, disrupting the interaction of other molecules with MUC1 ED is useful in treating these disease, in particular cancer.
