Genetic determinants of chromatin reveal prostate cancer risk mediated by context-dependent gene regulation

Many genetic variants affect disease risk by altering context-dependent gene regulation. Such variants are difficult to study mechanistically using current methods that link genetic variation to steady-state gene expression levels, such as expression quantitative trait loci (eQTLs). To address this challenge, we developed the cistrome-wide association study (CWAS), a framework for identifying genotypic and allele-specific effects on chromatin that are also associated with disease. In prostate cancer, CWAS identified regulatory elements and androgen receptor-binding sites that explained the association at 52 of 98 known prostate cancer risk loci and discovered 17 additional risk loci. CWAS implicated key developmental transcription factors in prostate cancer risk that are overlooked by eQTL-based approaches due to context-dependent gene regulation. We experimentally validated associations and demonstrated the extensibility of CWAS to additional epigenomic datasets and phenotypes, including response to prostate cancer treatment. CWAS is a powerful and biologically interpretable paradigm for studying variants that influence traits by affecting transcriptional regulation. Cistrome-wide association study (CWAS) is an approach for nominating variants that impact traits through effects on chromatin state. CWAS performed on 307 prostate cistromes identifies candidate loci for prostate cancer and androgen-related traits.
This work is supported by grants from the PhRMA Foundation and the Kure It Cancer Research Foundation (S.C.B.). The androgen deprivation GWAS was supported in part by the National Cancer Institute of the National Institutes of Health under award numbers U10CA180820, U10CA180794 and UG1CA233180 (C.J.S.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. We are grateful to the E3805: CHAARTED investigators; the patients who participated in the trial; the Prostate Cancer Foundation Mazzone Awards; and Sanofi for partial financial support and supplying docetaxel for early use (C.J.S.). In addition, we acknowledge Public Health Service grants CA180794, CA180820, CA23318, CA66636, CA21115, CA49883, CA16116, CA21076, CA27525, CA13650, CA14548, CA35421, CA32102, CA31946, CA04919, CA107868 and CA184734 (C.J.S.). We are grateful for the generous support of Rebecca and Nathan Milikowsky and Debbie and Bob First (S.C.B.).