Baxter, JS, Johnson, N, Tomczyk, K et al. (180 more authors) (2021) Functional annotation of the 2q35 breast cancer risk locus implicates a structural variant in influencing activity of a long-range enhancer element. The American Journal of Human Genetics, 108 (7). pp. 1190-1203. ISSN 0002-9297
Abstract
A combination of genetic and functional approaches has identified three independent breast cancer risk loci at 2q35. A recent fine-scale mapping analysis to refine these associations resulted in 1 (signal 1), 5 (signal 2), and 42 (signal 3) credible causal variants at these loci. We used publicly available in silico DNase I and ChIP-seq data with in vitro reporter gene and CRISPR assays to annotate signals 2 and 3. We identified putative regulatory elements that enhanced cell-type-specific transcription from the IGFBP5 promoter at both signals (30- to 40-fold increased expression by the putative regulatory element at signal 2, 2- to 3-fold by the putative regulatory element at signal 3). We further identified one of the five credible causal variants at signal 2, a 1.4 kb deletion (esv3594306), as the likely causal variant; the deletion allele of this variant was associated with an average additional increase in IGFBP5 expression of 1.3-fold (MCF-7) and 2.2-fold (T-47D). We propose a model in which the deletion allele of esv3594306 juxtaposes two transcription factor binding regions (annotated by estrogen receptor alpha ChIP-seq peaks) to generate a single extended regulatory element. This regulatory element increases cell-type-specific expression of the tumor suppressor gene IGFBP5 and, thereby, reduces risk of estrogen receptor-positive breast cancer (odds ratio = 0.77, 95% CI 0.74–0.81, p = 3.1 × 10^−31).
Metadata
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Copyright, Publisher and Additional Information: | © 2021 The Authors. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). | ||||||
Keywords: | breast cancer risk; functional annotation; risk locus | ||||||
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Institution: | The University of Sheffield | ||||||
Academic Units: | The University of Sheffield > Faculty of Medicine, Dentistry and Health (Sheffield) | ||||||
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Depositing User: | Symplectic Sheffield | ||||||
Date Deposited: | 08 Jul 2021 13:05 | ||||||
Last Modified: | 08 Jul 2021 13:05 | ||||||
Status: | Published | ||||||
Publisher: | Elsevier BV | ||||||
Refereed: | Yes | ||||||
Identification Number: | https://doi.org/10.1016/j.ajhg.2021.05.013 | ||||||
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