Antibody responses to OGFr and OGFr-ARF in breast and ovarian cancer patients with antibodies to MUC1. All serum samples were diluted (1:200) and tested as described above. A melanoma patient found to have antibodies to both OGFr-ARF and recombinant OGFr (K8), and one which had neither (K26), were included as controls. Also included are three normal donor serum samples. Using the criteria of four standard deviations above the mean of the normal donor response, 5/6 of the patient samples had an elevated antibody response to recombinant OGFr, and 1/6 (BT-2) to OGFr-ARF.