Antibody responses to recombinant OGFr and OGFr-ARF in metastatic non-small cell lung cancer (A) and hormone refractory prostate cancer (B) patients. ELISA plates were coated with the antigens indicated and incubated overnight at 4°C with serum diluted 1:800. Using a criterion of 3-fold elevation (OD at 450 nm) above that obtained with the control antigen (MUC1 peptide), there were 5/24 responses to OGFr-ARF in the lung cancer group. In the prostate cancer group, there were 3/25 responses to OGFr-ARF and 1/25 to recombinant OGFr.