A method is provided for treating a disease or condition characterized by aberrant epithelial cell proliferation and/or migration. One step of the method can include administering to a mammal an agent which disrupts an isolated protein complex including: insulin-like growth factor I (IGF-I)； an insulin-like growth factor binding protein (IGFBP) selected from IGFBP-3 and IGFBP-5； and vitronectin； or which prevents formation of the isolated protein complex, to thereby treat the disease or condition in the mammal. The agent is selected from the group consisting a polypeptide that is distinguished from IGF-II by substitution of at least one amino acid residue, wherein the polypeptide disrupts the isolated protein complex.
