Identification Of Novel Cancer Target Genes By Combining Data From The Cancer Genome-Wide Association Studies (Gwas), Regulatory Dna Elements And The Cancer Genome Atlas (Tcga)

Unlike tumors that develop because of somatic genetic alterations such as frequent coding mutations or chromosomal deletions, amplifications or translocations, some tumors are addicted to expression of certain genes for their sustained proliferation and survival - for example, LIM domain only 1 (LMO1) expression in neuroblastoma (NB). Numerous genome-wide association studies (GWAS) have identified significant associations between germline single-nucleotide polymorphisms (SNPs), many in the non-coding genome, and cancer. A robust genome-wide association has been reported previously between an intronic LMO1 SNP and NB susceptibility. By further sequencing and epigenetic fine mapping of the SNP locus, it was demonstrated that the causal SNP is part of a transcription factor binding site within an enhancer element, regulates expression of LMO1 and in turn increases the tumorigenic potential. To identify additional examples of regulatory SNPs as cancer drivers, we overlaid published genome-wide significant cancer associations with active chromatin marks from Encyclopedia of DNA Elements and searched for SNPs that resided within gene regulatory elements. To map these SNPs to candidate genes and determine direction of effect, we co-localized GWAS signals with expression quantitative trait (eQTL) signals from the Genotype-Tissue Expression (GTEx) Consortium database. Lastly, we checked for gene amplification and/or overexpression of the mapped genes in the Cancer Genome Atlas (TCGA) data to identify a set of target genes that not only exhibit significant cancer association in GWAS, but also have evidence for epigenetic regulation and propensity for amplification and/or overexpression in tumors. We identified more than 25 novel cancer-target pairs with strong germline, regulatory and somatic evidence. A look up through synthetic lethality screen data available in-house suggested that several of these targets are self-lethal, further underscoring their importance for cancer cell proliferation and survival. Additional in vitro experiments are being planned to further validate the targets. Citation Format: Diptee A. Kulkarni, Karl Guo, Junping Jing, Mugdha Khaladkar, Kijoung Song, Coco Dong, David Cooper, Benjamin Schwartz. Identification of novel cancer target genes by combining data from the cancer genome-wide association studies (GWAS), regulatory DNA elements and The Cancer Genome Atlas (TCGA) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 236.