|As part of identifying new ovarian cancer biomarkers, single-chain variable fragment antibodies (scFv) were positively selected using cancer derived sera (left) and then negatively selected using normal sera (right).
Ovarian cancer is a “silent killer” because symptoms generally do not present themselves until the disease has advanced. The discovery of novel early detection biomarkers may offer a way to reduce the morbidity and mortality caused by ovarian cancer. In this study, 108 antibodies from a single antibody variable fragment antibody (scFv) library were selected for their recognition and specificity to ovarian cancer proximal fluid or serum samples. Resulting scFvs were printed on antibody microarrays and incubated with pooled sera from cancer patients or controls, enabling the selection of antibodies that best discriminated markers of ovarian cancer in a successive manner. The top 19 scFvs were incubated on a nucleic acid programmable protein array to identify their protein targets. Targets for 15/19 scFvs were identified, some of which overlapped, increasing the probability that the target is a marker for ovarian cancer. Dot plots were used to validate that the scFvs were specific for their targets and that their targets were overexpressed in samples from ovarian cancer patients. Together, this work demonstrates a new pipeline to identify antibodies that bind proteins elevated in serum samples from cancer patients, which can be subsequently analyzed for their usefulness as an ovarian cancer biomarker.
Use of a Single Chain Antibody Library for Ovarian Cancer Biomarker Discovery
Arturo B. Ramirez, Christian M. Loch, Yuzheng Zhang, Yan Liu, Xiaohong Wang, Elizabeth A. Wayner, Jonathon E. Sargent, Sahar Sibani, Eugenie Hainsworth, Eliseo A Mendoza, Ralph Eugene, Joshua LaBaer, Nicole D. Urban, Martin W. McIntosh and Paul D. Lampe
Mol. Cell. Proteomics, published online May 13, 2010
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