| 1. |
- Sampson, Joshua N., et al.
(författare)
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Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for 13 Cancer Types
- 2015
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 107:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. Results: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, h(l)(2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE = 0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Conclusion: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
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| 2. |
- Machiela, Mitchell J., et al.
(författare)
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Characterization of Large Structural Genetic Mosaicism in Human Autosomes
- 2015
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 96:3, s. 487-497
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Tidskriftsartikel (refereegranskat)abstract
- Analyses of genome-wide association study (GWAS) data have revealed that detectable genetic mosaicism involving large (>2 Mb) structural autosomal alterations occurs in a fraction of individuals. We present results for a set of 24,849 genotyped individuals (total GWAS set II [TGSII]) in whom 341 large autosomal abnormalities were observed in 168 (0.68%) individuals. Merging data from the new TGSII set with data from two prior reports (the Gene-Environment Association Studies and the total GWAS set I) generated a large dataset of 127,179 individuals; we then conducted a meta-analysis to investigate the patterns of detectable autosomal mosaicism (n = 1,315 events in 925 [0.73%] individuals). Restricting to events >2 Mb in size, we observed an increase in event frequency as event size decreased. The combined results underscore that the rate of detectable mosaicism increases with age (p value = 5.5 x 3 10(-31)) and is higher in men (p value = 0.002) but lower in participants of African ancestry (p value = 0.003). In a subset of 47 individuals from whom serial samples were collected up to 6 years apart, complex changes were noted over time and showed an overall increase in the proportion of mosaic cells as age increased. Our large combined sample allowed for a unique ability to characterize detectable genetic mosaicism involving large structural events and strengthens the emerging evidence of non-random erosion of the genome in the aging population.
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| 3. |
- Machiela, Mitchell J, et al.
(författare)
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Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome
- 2016
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- To investigate large structural clonal mosaicism of chromosome X, we analysed the SNP microarray intensity data of 38,303 women from cancer genome-wide association studies (20,878 cases and 17,425 controls) and detected 124 mosaic X events >2 Mb in 97 (0.25%) women. Here we show rates for X-chromosome mosaicism are four times higher than mean autosomal rates; X mosaic events more often include the entire chromosome and participants with X events more likely harbour autosomal mosaic events. X mosaicism frequency increases with age (0.11% in 50-year olds; 0.45% in 75-year olds), as reported for Y and autosomes. Methylation array analyses of 33 women with X mosaicism indicate events preferentially involve the inactive X chromosome. Our results provide further evidence that the sex chromosomes undergo mosaic events more frequently than autosomes, which could have implications for understanding the underlying mechanisms of mosaic events and their possible contribution to risk for chronic diseases.
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| 4. |
- Manning, Alisa, et al.
(författare)
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A Low-Frequency Inactivating AKT2 Variant Enriched in the Finnish Population Is Associated With Fasting Insulin Levels and Type 2 Diabetes Risk
- 2017
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Ingår i: Diabetes. - : AMER DIABETES ASSOC. - 0012-1797 .- 1939-327X. ; 66:7, s. 2019-2032
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Tidskriftsartikel (refereegranskat)abstract
- To identify novel coding association signals and facilitate characterization of mechanisms influencing glycemic traits and type 2 diabetes risk, we analyzed 109,215 variants derived from exome array genotyping together with an additional 390,225 variants from exome sequence in up to 39,339 normoglycemic individuals from five ancestry groups. We identified a novel association between the coding variant (p.Pro50Thr) in AKT2 and fasting plasma insulin (FI), a gene in which rare fully penetrant mutations are causal for monogenic glycemic disorders. The low-frequency allele is associated with a 12% increase in FI levels. This variant is present at 1.1% frequency in Finns but virtually absent in individuals from other ancestries. Carriers of the FI-increasing allele had increased 2-h insulin values, decreased insulin sensitivity, and increased risk of type 2 diabetes (odds ratio 1.05). In cellular studies, the AKT2-Thr50 protein exhibited a partial loss of function. We extend the allelic spectrum for coding variants in AKT2 associated with disorders of glucose homeostasis and demonstrate bidirectional effects of variants within the pleckstrin homology domain of AKT2.
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| 5. |
- Barrett, Jennifer H., et al.
(författare)
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Fine mapping of genetic susceptibility loci for melanoma reveals a mixture of single variant and multiple variant regions
- 2015
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 136:6, s. 1351-1360
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Tidskriftsartikel (refereegranskat)abstract
- At least 17 genomic regions are established as harboring melanoma susceptibility variants, in most instances with genome-wide levels of significance and replication in independent samples. Based on genome-wide single nucleotide polymorphism (SNP) data augmented by imputation to the 1,000 Genomes reference panel, we have fine mapped these regions in over 5,000 individuals with melanoma (mainly from the GenoMEL consortium) and over 7,000 ethnically matched controls. A penalized regression approach was used to discover those SNP markers that most parsimoniously explain the observed association in each genomic region. For the majority of the regions, the signal is best explained by a single SNP, which sometimes, as in the tyrosinase region, is a known functional variant. However in five regions the explanation is more complex. At the CDKN2A locus, for example, there is strong evidence that not only multiple SNPs but also multiple genes are involved. Our results illustrate the variability in the biology underlying genome-wide susceptibility loci and make steps toward accounting for some of the missing heritability. What's new? In genome-wide association studies, researchers identify genetic variants that frequently associate with a particular disease, though the variants identified may not contribute to the molecular cause of the disease. This study took a closer look at 17 regions associated with melanoma, fine mapping the regions both in people with melanoma and in healthy controls. Though single SNPs account for the association in some regions, they found that in a few regions, several SNPs - and possibly multiple genes - contributed to the association signal. These findings illustrate the importance of not overlooking the interaction between multiple genetic markers when conducting such studies.
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| 6. |
- Zhang, Tongwu, et al.
(författare)
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Cell-type-specific eQTL of primary melanocytes facilitates identification of melanoma susceptibility genes
- 2018
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Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1088-9051 .- 1549-5469. ; 28:11, s. 1621-1635
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Tidskriftsartikel (refereegranskat)abstract
- Most expression quantitative trait locus (eQTL) studies to date have been performed in heterogeneous tissues as opposed to specific cell types. To better understand the cell-type-specific regulatory landscape of human melanocytes, which give rise to melanoma but account for <5% of typical human skin biopsies, we performed an eQTL analysis in primary melanocyte cultures from 106 newborn males. We identified 597,335 cis-eQTL SNPs prior to linkage disequilibrium (LD) pruning and 4997 eGenes (FDR < 0.05). Melanocyte eQTLs differed considerably from those identified in the 44 GTEx tissue types, including skin. Over a third of melanocyte eGenes, including key genes in melanin synthesis pathways, were unique to melanocytes compared to those of GTEx skin tissues or TCGA melanomas. The melanocyte data set also identified trans-eQTLs, including those connecting a pigmentation-associated functional SNP with four genes, likely through cis-regulation of IRF4. Melanocyte eQTLs are enriched in cis-regulatory signatures found in melanocytes as well as in melanoma-associated variants identified through genome-wide association studies. Melanocyte eQTLs also colocalized with melanoma GWAS variants in five known loci. Finally, a transcriptome-wide association study using melanocyte eQTLs uncovered four novel susceptibility loci, where imputed expression levels of five genes (ZFP90, HEBP1, MSC, CBWD1, and RP11-383H13.1) were associated with melanoma at genome-wide significant P-values. Our data highlight the utility of lineage-specific eQTL resources for annotating GWAS findings, and present a robust database for genomic research of melanoma risk and melanocyte biology.
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| 7. |
- Taylor, Nicholas J, et al.
(författare)
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Estimating CDKN2A mutation carrier probability among global familial melanoma cases using GenoMELPREDICT
- 2019
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Ingår i: Journal of the American Academy of Dermatology. - : Elsevier BV. - 0190-9622 .- 1097-6787. ; 81:2, s. 386-394
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Although rare in the general population, highly penetrant germline mutations in CDKN2A are responsible for 5-40% of melanoma cases reported in melanoma-prone families. We sought to determine whether MELPREDICT was generalizable to a global series of melanoma families and whether performance improvements can be achieved.METHODS: 2,116 familial melanoma cases were ascertained by the international GenoMEL Consortium. We recapitulated the MELPREDICT model within our data (GenoMELPREDICT) to assess performance improvements by adding phenotypic risk factors and history of pancreatic cancer. We report areas under the curve (AUC) with 95% confidence intervals (CI) along with net reclassification indices (NRI) as performance metrics.RESULTS: MELPREDICT performed well (AUC=0.752; 95%CI: 0.730, 0.775), and GenoMELPREDICT performance was similar (AUC=0.748; 95% CI: 0.726, 0.771). Adding a reported history of pancreatic cancer yielded discriminatory improvement (p<0.0001) in GenoMELPREDICT (AUC=0.772; 95%CI: 0.750, 0.793; NRI=0.40). Including phenotypic risk factors did not improve performance.CONCLUSION: The MELPREDICT model functioned well in a global dataset of familial melanoma cases. Adding pancreatic cancer history improved model prediction. GenoMELPREDICT is a simple tool for predicting CDKN2A mutational status among melanoma patients from melanoma-prone families and can aid in counselling these patients towards genetic testing or cancer risk counselling.
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| 8. |
- Taylor, Nicholas J., et al.
(författare)
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Germline Variation at CDKN2A and Associations with Nevus Phenotypes among Members of Melanoma Families
- 2017
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 137:12, s. 2606-2612
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Tidskriftsartikel (refereegranskat)abstract
- Germline mutations in CDKN2A are frequently identified among melanoma kindreds and are associated with increased atypical nevus counts. However, a clear relationship between pathogenic CDKN2A mutation carriage and other nevus phenotypes including counts of common acquired nevi has not yet been established. Using data from GenoMEL, we investigated the relationships between CDKN2A mutation carriage and 2-mm, 5-mm, and atypical nevus counts among blood-related members of melanoma families. Compared with individuals without a pathogenic mutation, those who carried one had an overall higher prevalence of atypical (odds ratio = 1.64; 95% confidence interval = 1.18–2.28) nevi but not 2-mm nevi (odds ratio = 1.06; 95% confidence interval = 0.92–1.21) or 5-mm nevi (odds ratio = 1.26; 95% confidence interval = 0.94–1.70). Stratification by case status showed more pronounced positive associations among non-case family members, who were nearly three times (odds ratio = 2.91; 95% confidence interval = 1.75–4.82) as likely to exhibit nevus counts at or above the median in all three nevus categories simultaneously when harboring a pathogenic mutation (vs. not harboring one). Our results support the hypothesis that unidentified nevogenic genes are co-inherited with CDKN2A and may influence carcinogenesis.
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| 9. |
- Helgadottir, Hildur, et al.
(författare)
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Phenocopies in melanoma-prone families with germ-line CDKN2A mutations
- 2018
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Ingår i: Genetics in Medicine. - : Elsevier BV. - 1098-3600. ; 20:9, s. 1087-1090
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Carriers of CDKN2A mutations have high risks of melanoma and certain other cancers. In this study we examined the occurrence of tumors among CDKN2A wild type (wt) members of melanoma-prone families with CDKN2A mutations. Methods: Swedish and US melanoma-prone families with CDKN2A mutations were included. Data was collected on tumors diagnosed among family members. Among the CDKN2A mutated families, members with CDKN2A wt status who were diagnosed with melanoma were designated phenocopies. Results: Of patients with melanoma in the CDKN2A mutated families (n = 266), 7.1%, were seen among members with CDKN2A wt status (phenocopy rate). Among the CDKN2A wt family members of the CDKN2A mutated families (n = 256), 7.4% were diagnosed with melanoma. The prospective relative risk for melanomas was significantly higher among the CDKN2A wt subjects compared with population-based controls (7.4 (95% confidence interval 1.7–33.2)), while no elevated risks of nonmelanoma cancers were seen and their offspring did not have significantly elevated risks of melanoma or other cancers. Conclusion: Members of CDKN2A mutation carrying families who test negative for their family’s mutation have moderately increased risk for melanoma and should, in addition to being considered for continuing dermatologic surveillance, be encouraged to follow sun safety recommendations and practice skin self-exams.
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| 10. |
- Yang, Xiaohong R., et al.
(författare)
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Multiple rare variants in high-risk pancreatic cancer-related genes may increase risk for pancreatic cancer in a subset of patients with and without germline CDKN2A mutations
- 2016
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Ingår i: Human Genetics. - : Springer Science and Business Media LLC. - 0340-6717 .- 1432-1203. ; 135:11, s. 1241-1249
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Tidskriftsartikel (refereegranskat)abstract
- The risk of pancreatic cancer (PC) is increased in melanoma-prone families but the causal relationship between germline CDKN2A mutations and PC risk is uncertain, suggesting the existence of non-CDKN2A factors. One genetic possibility involves patients having mutations in multiple high-risk PC-related genes; however, no systematic examination has yet been conducted. We used next-generation sequencing data to examine 24 putative PC-related genes in 43 PC patients with and 23 PC patients without germline CDKN2A mutations and 1001 controls. For each gene and the four pathways in which they occurred, we tested whether PC patients (overall or CDKN2A+ and CDKN2A− cases separately) had an increased number of rare nonsynonymous variants. Overall, we identified 35 missense variants in PC patients, 14 in CDKN2A+ and 21 in CDKN2A− PC cases. We found nominally significant associations for mismatch repair genes (MLH1, MSH2, MSH6, PMS2) in all PC patients and for ATM, CPA1, and PMS2 in CDKN2A− PC patients. Further, nine CDKN2A+ and four CDKN2A− PC patients had rare potentially deleterious variants in multiple PC-related genes. Loss-of-function variants were only observed in CDKN2A− PC patients, with ATM having the most pathogenic variants. Also, ATM variants (n = 5) were only observed in CDKN2A− PC patients with a family history that included digestive system tumors. Our results suggest that a subset of PC patients may have increased risk because of germline mutations in multiple PC-related genes.
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