Proteogenomic detection of circulating biomarkers for clinical oncology.

Abstract

e15010 Background: Circulating biomarkers have the potential to detect cancer in its earliest stages and monitor patients in remission. The integration of proteogenomics in circulating biomarkers may transform the molecular diagnostics of cancer and accelerate basic and clinical oncology research. Proteomics bridges the gaps of functional information lost due to post-transcriptional and post-translational modifications in a genomic approach. A recent study showed that adding just 8 protein biomarkers to a panel of circulating DNA biomarkers increased the diagnostic accuracy up to 98% sensitivity and 99% specificity. However, the proteogenomic approach normally requires the use of multiple different assay technologies and laboratory workflows, including mass spectrometry. Methods: MosaicNeedles are densely integrated nanoneedle sensors fabricated on a planar substrate that integrates proteogenomic analysis in one platform. 94,000 sensors with more than 2 billion total nanoneedles can be integrated on to a standard SBS plate, which can be configured into 96, 384 or 1536 well format. Each sensor contains an array of nanoneedles, dedicated to detecting one analyte of interest. All nanoneedles comprising the same sensor are functionalized with the same capture probes. The capture probe can be either an antibody for protein detection or an oligonucleotide with a specific target sequence to a DNA fragment, mRNA, or miRNA of interest. Results: At low analyte concentration, the binding of proteins to the nanoneedles follows a Poisson distribution. Therefore, statistically, no more than one molecule is bound per nanoneedle. A further addition of aptamers or antibodies will form a sandwich complex with the target analyte. Since each of the nanoneedles has an intrinsic optical resonance spectrum and will red-shift as the sandwich complex forms on its surface, the number of analytes can be quantitated by simply counting the number of nanoneedles that display a color change. At high analyte concentration, each nanoneedle has more than one analyte, so the number of analytes can be calculated by averaging the spectrum shifts of all nanoneedles. This combined single molecule counting (digital) and spectrum shift (analog) analysis allows the platform to detect both high abundance and low abundance protein analytes in one reaction. A 10,000-plex study can be achieved with a total of 2.5 billion nanoneedles on a 50mm by 50mm consumable. In this consumable, a 2,000-plex proteome and 8,000 cell-free DNA fragments can be detected. Conclusions: A full proteogenomic quantification can be performed on the NanoMosaic platform in one reaction with high sensitivity and large dynamic range. It simplifies the workflow and allows users to integrate proteomic and genomic information to discover new circulating biomarkers.