title: Quantitation of HER2 and telomerase biomarkers in solid tumors with IgY antibodies and nanocrystal detection.
abstract: In an effort to improve affinity biomarker validation in fixed patient tissue specimens, we have developed a novel quantum dot-based bioimaging system that utilizes chicken IgY antibody for high sensitivity and specificity relative quantitation of cancer proteins. Monospecific, polyclonal IgYs were generated against human HER2 and telomerase, and analytically validated for specificity by western blot and immunohistochemistry on tumor and normal cells and for relative affinity by layered peptide array (LPA). IgYs bound desired targets in cell lines and fixed tissues and showed greater affinity than commercial mammalian antibodies for both HER2 and telomerase proteins. In tissue microarray experiments, HER2 quantitation with IgY antibody and quantum dot imaging correlated well with chromogenic in situ hybridization (CISH), whereas telomerase quantitation suggested a trend toward correlation with prostate cancer Gleason Grade and differentiation. Although patient numbers were small, these findings demonstrate the feasibility of relative quantitation of cancer biomarkers with IgY and quantum dot fluorophores, and show promise for rigorous clinical validation in large patient cohorts.
authors.affiliation: NIST-NCI EDRN Cancer Biomarker Reference Laboratory, National Institute of Standards and Technology, Gaithersburg, MD, USA. yan.xiao@nist.gov
authors.forename: Yan
authors.initials: Y
authors.lastname: Xiao
authors.forename: Xiugong
authors.initials: X
authors.lastname: Gao
authors.forename: Gallya
authors.initials: G
authors.lastname: Gannot
authors.forename: Michael R
authors.initials: MR
authors.lastname: Emmert-Buck
authors.forename: Sudhir
authors.initials: S
authors.lastname: Srivastava
authors.forename: Paul D
authors.initials: PD
authors.lastname: Wagner
authors.forename: Michael D
authors.initials: MD
authors.lastname: Amos
authors.forename: Peter E
authors.initials: PE
authors.lastname: Barker
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000276:immunology*; D015153:Blotting, Western; D002645:Chickens; D006801:Humans; D007124:Immunoenzyme Techniques; D007136:Immunoglobulins / Q000276:immunology*; D017403:In Situ Hybridization; D053758:Nanoparticles / Q000737:chemistry*; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology; D045663:Quantum Dots; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology*; D019098:Telomerase / Q000276:immunology*; D046888:Tissue Array Analysis; D014407:Tumor Cells, Cultured
chemical_list: D014408:Biomarkers, Tumor; D007136:Immunoglobulins; D018719:Erb-b2 Receptor Tyrosine Kinases; D019098:Telomerase; C016512:IgY