Asthma is a common respiratory disorder characterized by recurrent episodes of coughing, wheezing and breathlessness. Although environmental factors such as allergen exposure are risk factors in the development of asthma, both twin and family studies point to a strong genetic component. To date, linkage studies have identified more than a dozen genomic regions linked to asthma. In this study, we performed a genome-wide scan on 460 Caucasian families and identified a locus on chromosome 20p13 that was linked to asthma (log(10) of the likelihood ratio (LOD), 2.94) and bronchial hyperresponsiveness (LOD, 3.93). A survey of 135 polymorphisms in 23 genes identified the ADAM33 gene as being significantly associated with asthma using case-control, transmission disequilibrium and haplotype analyses (P = 0.04 0.000003). ADAM proteins are membrane-anchored metalloproteases with diverse functions, which include the shedding of cell-surface proteins such as cytokines and cytokine receptors. The identification and characterization of ADAM33, a putative asthma susceptibility gene identified by positional cloning in an outbred population, should provide insights into the pathogenesis and natural history of this common disease.
Immunohistochemistry
(IHC) combined with fluorescence microscopy
provides an important and widely used tool for researchers and pathologists
to image multiple biomarkers in tissue specimens. However, multiplex
IHC using standard fluorescence microscopy is generally limited to
3–5 different biomarkers, with hyperspectral or multispectral
methods limited to 8. We report the development of a new technology
based on novel photocleavable mass-tags (PC-MTs) for facile antibody
labeling, which enables highly multiplexed IHC based on MALDI mass
spectrometric imaging (MALDI-IHC). This approach significantly exceeds
the multiplexity of both fluorescence- and previous cleavable mass-tag-based
methods. Up to 12-plex MALDI-IHC was demonstrated on mouse brain,
human tonsil, and breast cancer tissues specimens, reflecting the
known molecular composition, anatomy, and pathology of the targeted
biomarkers. Novel dual-labeled fluorescent PC-MT antibodies and label-free
small-molecule mass spectrometric imaging greatly extend the capability
of this new approach. MALDI-IHC shows promise for use in the fields
of tissue pathology, tissue diagnostics, therapeutics, and precision
medicine.
Background: Genome-wide changes in DNA methylation are an epigenetic phenomenon that can lead to the development of disease. The study of global DNA methylation utilizes technology that requires both expensive equipment and highly specialized skill sets.
Colorectal cancer (CRC) is the second leading cause of cancer deaths in the U.S and Western world. Despite increased screening and advances in treatment, the mortality rate (ca. 50,000/year) and high national health-care burden for CRC are likely to remain high unless an effective non-invasive screening test for CRC is instituted for a large segment of the population. Blood-based protein biomarkers hold great promise for early disease diagnosis and personalized medicine; yet robust and reproducible multiplexing platforms and methodologies have lagged behind their genomic counterparts.
Here, we report the development of a novel, multiplexed, hybrid immunoassay for CRC that is formatted on barcoded VeraCode™ micro-beads, which have until now only been used for genomic assays. The method combines a sandwich immunoassay format for detection of serum protein biomarkers with an antigen assay for autoantibody detection. The serum protein biomarkers CEA and GDF15 as well as autoantibodies to the p53 tumor associated antigen (TAA) were used to exemplify the method. This multiplex biomarker panel was configured to run on Illumina’s holographically barcoded VeraCode™ micro-bead platform, which is capable of measuring hundreds of analytes simultaneously in a single well from small volumes of blood (<50 μL) using a 96-well industry standard microtiter plate. This novel use of the VeraCode™ micro-bead platform translates into a potentially low volume, high throughput, multiplexed assay for CRC, for the purposes of biomarker validation, as well as patient screening, diagnostics and prognostics. In an evaluation of a 186 patient sera training set (CRC and normal), we obtained a diagnostic sensitivity of 54% and a specificity of 98%. We anticipate that by expanding and refining the biomarkers in this initial panel, and performing more extensive clinical validations, such an assay could ultimately provide a basis for CRC population screening to complement the more invasive, expensive and low throughput (but highly sensitive and specific) colonoscopy.
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