The present invention provides, in part, methods for treating a tumor in a human subject comprising inhibiting IGF-1 receptor signaling, methods of determining whether a tumor is more or less likely to respond to such treatment, and compositions for practicing such methods. In particular embodiments, the invention provides fully human, humanized, or chimeric anti-IGF-1R antibodies that bind human IGF-1R, IGF-1R-binding fragments and derivatives of such antibodies, and IGF-1R-binding polypeptides comprising such fragments. Other embodiments provide nucleic acids encoding such antibodies, antibody fragments and derivatives and polypeptides, cells comprising such polynucleotides, methods of making such antibodies, antibody fragments and derivatives and polypeptides, and methods of using such antibodies, antibody fragments and derivatives and polypeptides, including methods of treating or diagnosing subjects having IGF-1R-related disorders or conditions, and kits for practicing the foregoing.