Detection of Early-Stage Pancreatic Ductal Adenocarcinoma From Blood Samples : Results of a Multiplex Biomarker Signature Validation Study

INTRODUCTION: The IMMray PanCan-d test combines an 8-plex biomarker signature with CA19-9 in a proprietary algorithm to detect pancreatic ductal adenocarcinoma (PDAC) in serum samples. This study aimed to validate the clinical performance of the IMMray PanCan-d test and to better understand test performance in Lewis-null (le/le) individuals who cannot express CA19-9. METHODS: Serum samples from 586 individuals were analyzed with the IMMray PanCan-d biomarker signature and CA19-9 assay, including 167 PDAC samples, 203 individuals at high risk of familial/hereditary PDAC, and 216 healthy controls. Samples were collected at 11 sites in the United States and Europe. The study was performed by Immunovia, Inc (Marlborough, MA), and sample identity was blinded throughout the study. Test results were automatically generated using validated custom software with a locked algorithm and predefined decision value cutoffs for sample classification. RESULTS: The IMMray PanCan-d test distinguished PDAC stages I and II (n = 56) vs high-risk individuals with 98% specificity and 85% sensitivity and distinguished PDAC stages I-IV vs high-risk individuals with 98% specificity and 87% sensitivity. We identified samples with a CA19-9 value of 2.5 U/mL or less as probable Lewis-null (le/le) individuals. Excluding these 55 samples from the analysis increased the IMMray PanCan-d test sensitivity to 92% for PDAC stages I-IV (n = 157) vs controls (n = 379) while maintaining specificity at 99%; test sensitivity for PDAC stages I and II increased from 85% to 89%. DISCUSSION: These results demonstrate the IMMray PanCan-d blood test can detect PDAC with high specificity (99%) and sensitivity (92%).Peer reviewe

Design of antibody microarrays for global profiling of membrane proteins and soluble proteins

Antibody-based microarrays have emerged as an established proteomic technology allowing multiplexed and sensitive profiling of complex proteomes, in a high-throughput and miniaturized manner. Recently, numerous applicative efforts have been pursued generating disease-associated protein signatures that now could be further explored for improved disease diagnostics, prognostics and classification. The aim of this thesis, based on five original papers, was to develop the antibody microarray methodology even further, to allow for global proteome analysis. Accordingly, a miniaturization of the array features was established, allowing for high-density arrays to be fabricated. We showed that sensitive detection of protein analytes in pure system as well as complex serum samples could be achieved using this miniaturized recombinant antibody nanoarray set-up. In additional globalization efforts, we demonstrated that two, novel, recombinant antibody microarray set-ups, based on human scFv antibody fragments, could be designed for membrane protein profiling of intact cells and cell/tissue extracts, respectively. This will provide us with unique and novel means to delineate the membrane proteome, previously proven to be to be difficult to address using conventional proteomic approaches. Taking advantage of these technological developments in a follow-up applicative study, differentially expressed membrane proteins and water-soluble proteins were readily identified in preeclamptic placenta vs. normal placenta. The data showed that candidate disease-associated tissue protein signatures could be identified, that could help to decipher the complex features of preeclampsia at the molecular level. Finally, we demonstrated how a wide variety of protein analytes could be targeted in mantle cell lymphoma, adopting genome-based affinity proteomics, using a novel reverse-phase antibody microarray set-up. Altogether, these technological improvements will allow us to gain further insights into complex molecular pathways in health and disease

Design of recombinant antibody microarrays for complex proteome analysis: Choice of sample labeling-tag and solid support

Antibody-based microarray is a novel technology with great potential within high-throughput proteomics. The process of designing high-performing antibody (protein) microarrays has, however, turned out to be a challenging process. In this study, we have developed further our human recombinant single-chain variable-fragment (scFv) antibody microarray methodology by addressing two crucial technological issues, choice of sample labeling-tag and solid support. We examined the performance of a range of dyes in a one- or two-color approach on a selection of solid supports providing different surface and coupling chemistries, and surface structures. The set-ups were evaluated in terms of sensitivity specificity, and selectivity. The results showed that a one-color approach, based on NHS-biotin (or ULS-biotin) labeling, on black polymer Maxisorb slides (or Nexterion slide H) was the superior approach for targeting low-abundant (pg/mL) analytes in nonfractionated, complex proteomes, such as human serum or crude cell supernatants. Notably, microarrays displaying adequate spot morphologies, high S/Ns, minimized nonspecific binding, and most importantly a high selectivity, specificity, and sensitivity (>= fM range) were obtained. Taken together, we have designed the first generation of a high-performing recombinant scFv antibody microarray technology platform on black polymer Maxisorb slides for sensitive profiling of low-abundant analytes in nonfractionated biotinylated complex proteomes

Design of recombinant antibody microarrays for cell surface membrane proteomics

Generating proteomic maps of membrane proteins, common targets for therapeutic interventions and disease diagnostics, has turned out to be a major challenge. Antibody-based microarrays are among the novel rapidly evolving proteomic technologies that may enable global proteome analysis to be performed. Here, we have designed the first generation of a scaleable human recombinant scFv antibody microarray technology platform for cell surface membrane proteomics as well as glycomics targeting intact cells. The results showed that rapid and multiplexed profiling of the cell surface proteome (and glycome) could be performed in a highly specific and sensitive manner and that differential expression patterns due to external stimuli could be monitored

Design of atto-vial based recombinant antibody arrays combined with a planar wave-guide detection system

Antibody microarray is a rapidly emerging, powerful approach with great promise within high-throughput proteomics. However, before a truly proteome-wide analysis can be performed, the antibody array format needs to be miniaturized even further in order to enable ultradense arrays to be fabricated. To this end, we have designed and generated proof-of-concept for the first generation of an atto-vial based recombinant antibody array platform. Briefly, we have designed a novel nanostructured substrate using electron beam lithography. Vials, ranging in volume/size from 6 (200 nm in diameter) to 4000 aL (5 mu m in diameter), were fabricated. Human recombinant single-chain Fv antibody fragments, microarray adopted by design, were used as probes. The set-up was interfaced with planar wave-guide technology for evanescant field fluorescence detection. The results showed that protein analytes could be specifically detected in the subzeptomole range for pure systems, using vials down to 57 aL. Further, low-abundant (pg/mL) protein analytes could be detected in directly labeled complex proteomes, such as human whole serum, using 157 aL-vials. Taken together, these results outline the potential of the atto-vial array set-up for miniaturized affinity proteomics-based approaches

Evolution of a carbohydrate binding module into a protein-specific binder

A carbohydrate binding module, CBM4-2, derived front the xylanase (Xyn 10A) of Rhodothermus marinus has been used as a scaffold for molecular diversification. Its binding specificity has been evolved to recognise a quite different target, a human monoclonal IgG4. In order to understand the basis for this drastic change in specificity we have further investigated the target recognition of the IgG4-specific CBMs. Firstly, we defined that the structure target recognised by the selected CBM-variants was the protein and not the carbohydrates attached to the glycoprotein. We also identified key residues involved in the new specificity and/or responsible for the swap in specificity, from xylan to human IgG4. Specific changes present in all these CBMs included mutations not introduced in the design of the library from which the specific clones were selected. Reversion of such mutations led to a complete loss of binding to the target molecule, suggesting that they are critical for the recognition of human IgG4. Together with the mutations introduced at will, they had transformed the CBM scaffold into a protein binder. We have thus shown that the scaffold of CBM4-2 is able to harbour molecular recognition for either carbohydrate or protein structures. (c) 2005 Elsevier B.V. All rights reserved