Colorectal cancer (CRC) is a leading cause of mortality worldwide. We conducted a genome-wide association study meta-analysis of 100,204 CRC cases and 154,587 controls of European and east Asian ancestry, identifying 205 independent risk associations, of which 50 were unreported. We performed integrative genomic, transcriptomic and methylomic analyses across large bowel mucosa and other tissues. Transcriptome- and methylome-wide association studies revealed an additional 53 risk associations. We identified 155 high-confidence effector genes functionally linked to CRC risk, many of which had no previously established role in CRC. These have multiple different functions and specifically indicate that variation in normal colorectal homeostasis, proliferation, cell adhesion, migration, immunity and microbial interactions determines CRC risk. Crosstissue analyses indicated that over a third of effector genes most probably act outside the colonic mucosa. Our findings provide insights into colorectal oncogenesis and highlight potential targets across tissues for new CRC treatment and chemoprevention strategies.
- MeSH
- celogenomová asociační studie MeSH
- Evropané * genetika MeSH
- genetická predispozice k nemoci MeSH
- jednonukleotidový polymorfismus genetika MeSH
- kolorektální nádory * genetika MeSH
- lidé MeSH
- multiomika MeSH
- východní Asiaté * genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
BACKGROUND AND AIMS: Susceptibility genes and the underlying mechanisms for the majority of risk loci identified by genome-wide association studies (GWAS) for colorectal cancer (CRC) risk remain largely unknown. We conducted a transcriptome-wide association study (TWAS) to identify putative susceptibility genes. METHODS: Gene-expression prediction models were built using transcriptome and genetic data from the 284 normal transverse colon tissues of European descendants from the Genotype-Tissue Expression (GTEx), and model performance was evaluated using data from The Cancer Genome Atlas (n = 355). We applied the gene-expression prediction models and GWAS data to evaluate associations of genetically predicted gene-expression with CRC risk in 58,131 CRC cases and 67,347 controls of European ancestry. Dual-luciferase reporter assays and knockdown experiments in CRC cells and tumor xenografts were conducted. RESULTS: We identified 25 genes associated with CRC risk at a Bonferroni-corrected threshold of P < 9.1 × 10-6, including genes in 4 novel loci, PYGL (14q22.1), RPL28 (19q13.42), CAPN12 (19q13.2), MYH7B (20q11.22), and MAP1L3CA (20q11.22). In 9 known GWAS-identified loci, we uncovered 9 genes that have not been reported previously, whereas 4 genes remained statistically significant after adjusting for the lead risk variant of the locus. Through colocalization analysis in GWAS loci, we additionally identified 12 putative susceptibility genes that were supported by TWAS analysis at P < .01. We showed that risk allele of the lead risk variant rs1741640 affected the promoter activity of CABLES2. Knockdown experiments confirmed that CABLES2 plays a vital role in colorectal carcinogenesis. CONCLUSIONS: Our study reveals new putative susceptibility genes and provides new insight into the biological mechanisms underlying CRC development.
- Klíčová slova
- CABLES2, Colorectal Cancer, Susceptibility Genes, TWAS,
- MeSH
- alely MeSH
- celogenomová asociační studie MeSH
- genetická predispozice k nemoci * MeSH
- genový knockdown MeSH
- jednonukleotidový polymorfismus MeSH
- karcinogeneze genetika MeSH
- kohortové studie MeSH
- kolorektální nádory epidemiologie genetika MeSH
- lidé MeSH
- modely genetické * MeSH
- nádorové biomarkery genetika MeSH
- promotorové oblasti (genetika) genetika MeSH
- rizikové faktory MeSH
- sekvenování transkriptomu MeSH
- studie případů a kontrol MeSH
- xenogenní modely - testy protinádorové aktivity MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, N.I.H., Intramural MeSH
- Názvy látek
- nádorové biomarkery MeSH
Interindividual differences in DNA repair systems may play a role in modulating the individual risk of developing colorectal cancer. To better ascertain the role of DNA repair gene polymorphisms on colon and rectal cancer risk individually, we evaluated 15,419 single nucleotide polymorphisms (SNPs) within 185 DNA repair genes using GWAS data from the Colon Cancer Family Registry (CCFR) and the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), which included 8,178 colon cancer, 2,936 rectum cancer cases and 14,659 controls. Rs1800734 (in MLH1 gene) was associated with colon cancer risk (p-value = 3.5 × 10-6 ) and rs2189517 (in RAD51B) with rectal cancer risk (p-value = 5.7 × 10-6 ). The results had statistical significance close to the Bonferroni corrected p-value of 5.8 × 10-6 . Ninety-four SNPs were significantly associated with colorectal cancer risk after Binomial Sequential Goodness of Fit (BSGoF) procedure and confirmed the relevance of DNA mismatch repair (MMR) and homologous recombination pathways for colon and rectum cancer, respectively. Defects in MMR genes are known to be crucial for familial form of colorectal cancer but our findings suggest that specific genetic variations in MLH1 are important also in the individual predisposition to sporadic colon cancer. Other SNPs associated with the risk of colon cancer (e.g., rs16906252 in MGMT) were found to affect mRNA expression levels in colon transverse and therefore working as possible cis-eQTL suggesting possible mechanisms of carcinogenesis.
- Klíčová slova
- DNA repair, cancer susceptibility, colon cancer, genome-wide association studies, rectal cancer, single nucleotide polymorphisms,
- MeSH
- biologická variabilita populace genetika MeSH
- DNA modifikační methylasy genetika MeSH
- DNA vazebné proteiny genetika MeSH
- dospělí MeSH
- enzymy opravy DNA genetika MeSH
- genetická predispozice k nemoci * MeSH
- hodnocení rizik MeSH
- jednonukleotidový polymorfismus MeSH
- karcinogeneze genetika MeSH
- kolon patologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- MutL homolog 1 genetika MeSH
- nádorové supresorové proteiny genetika MeSH
- nádory rekta genetika patologie MeSH
- nádory tračníku genetika patologie MeSH
- oprava DNA genetika MeSH
- registrace statistika a číselné údaje MeSH
- rektum patologie MeSH
- senioři MeSH
- studie případů a kontrol MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Názvy látek
- DNA modifikační methylasy MeSH
- DNA vazebné proteiny MeSH
- enzymy opravy DNA MeSH
- MGMT protein, human MeSH Prohlížeč
- MLH1 protein, human MeSH Prohlížeč
- MutL homolog 1 MeSH
- nádorové supresorové proteiny MeSH
- RAD51B protein, human MeSH Prohlížeč
