Using custom protein microarrays to identify autoantibody biomarkers for the early detection of breast cancer.

Abstract #2003 Background: Cancer patients make antibodies to tumor-derived proteins that are potential biomarkers for early detection. To detect autoantibodies to tumor antigens in patient sera, we have adapted novel high-density custom protein microarrays (NAPPA) expressing 6,500 candidate tumor antigens for biomarker detection. These arrays are probed with sera from patients with early stage breast cancer and healthy women. Using this approach, we identified antibodies in the sera of breast cancer patients.
 Methods: 6,500 full-length human antigens were expressed using mammalian reticulocyte lysate and captured onto NAPPA protein microarrays. Protein expression (>90%) was confirmed with anti-GST antibodies. Patient sera were added, and bound IgG detected with secondary antibodies. Serum samples were obtained from 103 patients with stages I-III breast cancer, and 103 age-matched control women, all undergoing routine mammography.
 Results: Using high-density protein microarrays, sera from breast cancer patients (n=53) and healthy donor sera (n=53) were screened for autoantibodies to 6,500 protein antigens. Antigens were selected for further analysis if the 95 th percentile of signal of cases and controls were significantly different (p th percentile of controls was larger than the number expected due to random chance (p Conclusions : Custom in-situ protein microarrays can be used to detect serum tumor antigen-specific antibodies and enables the rapid, simultaneous detection of immunogenic tumor antigens from patient sera. These autoantibodies are being evaluated as potential biomarkers for the early diagnosis of breast cancer. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2003.