Development of a high-performance, blood-based screening diagnostic to detect early-stage breast cancer.

e22083 Background: Limitations of current screening mammography, particularly in younger women, demonstrate the need for an alternative breast cancer screening strategy. A non-invasive, easily interpreted and low cost test should address this need. Methods: Gene expression microarray analysis was carried out on 128 individual tumor samples representing over 20 tumor types, 86 samples representing 31 diverse normal tissue types, 68 tumor cell lines and 97 diverse normal primary cell cultures. Genes were ranked for elevated expression in either: i) a large number and variety of tumors relative to normal tissues, or ii) in breast tumors. Elevated expression was verified for a subset of genes using qPCR in a set of independent RNA samples. Proteins coded by genes elevated in breast cancer samples were analyzed in a retrospective training set of breast cancer patient sera samples with cancer-free patient and benign pathology controls using ELISA or bead-based detection assay. Results: Based on availability of suitable reagents, 25 candidate biomarkers were assessed in patient sera samples (31-227 patient samples per biomarker) using ELISA or bead-based assays. Individually, the performance of individual markers varied (ROC AUC, 0.51 - 0.88); however, when expression levels of the best performing markers were combined, the multiplex test demonstrated high-sensitivity (>80%) and specificity (>90%) in identifying early-stage breast cancer patients. Conclusions: A multiplex, proteomic-based approach may provide for a high-performance, blood-based screening diagnostic for breast cancer.