Publications by authors named "Jirong Long"

204 Publications

Novel strategy for disease risk prediction incorporating predicted gene expression and DNA methylation data: a multi-phased study of prostate cancer.

Cancer Commun (Lond) 2021 Sep 14. Epub 2021 Sep 14.

Cancer Epidemiology Division, Population Sciences in the Pacific Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, HI, 96813, USA.

Background: DNA methylation and gene expression are known to play important roles in the etiology of human diseases such as prostate cancer (PCa). However, it has not yet been possible to incorporate information of DNA methylation and gene expression into polygenic risk scores (PRSs). Here, we aimed to develop and validate an improved PRS for PCa risk by incorporating genetically predicted gene expression and DNA methylation, and other genomic information using an integrative method.

Methods: Using data from the PRACTICAL consortium, we derived multiple sets of genetic scores, including those based on available single-nucleotide polymorphisms through widely used methods of pruning and thresholding, LDpred, LDpred-funt, AnnoPred, and EBPRS, as well as PRS constructed using the genetically predicted gene expression and DNA methylation through a revised pruning and thresholding strategy. In the tuning step, using the UK Biobank data (1458 prevalent cases and 1467 controls), we selected PRSs with the best performance. Using an independent set of data from the UK Biobank, we developed an integrative PRS combining information from individual scores. Furthermore, in the testing step, we tested the performance of the integrative PRS in another independent set of UK Biobank data of incident cases and controls.

Results: Our constructed PRS had improved performance (C statistics: 76.1%) over PRSs constructed by individual benchmark methods (from 69.6% to 74.7%). Furthermore, our new PRS had much higher risk assessment power than family history. The overall net reclassification improvement was 69.0% by adding PRS to the baseline model compared with 12.5% by adding family history.

Conclusions: We developed and validated a new PRS which may improve the utility in predicting the risk of developing PCa. Our innovative method can also be applied to other human diseases to improve risk prediction across multiple outcomes.
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http://dx.doi.org/10.1002/cac2.12205DOI Listing
September 2021

Integrating genome and methylome data to identify candidate DNA methylation biomarkers for pancreatic cancer risk.

Cancer Epidemiol Biomarkers Prev 2021 Sep 8. Epub 2021 Sep 8.

University of Hawaii at Manoa

Background The role of methylation in pancreatic cancer (PC) risk remains unclear. We integrated genome and methylome data to identify CpG sites (CpGs) with the genetically predicted methylation to be associated with PC risk. We also studied gene expression to understand the identified associations. Methods Using genetic data and white blood cell methylation data from 1,595 subjects of European descent, we built genetic models to predict DNA methylation levels. After internal and external validation, we applied prediction models with satisfactory performance to the genetic data of 8,280 PC cases and 6,728 controls of European ancestry to investigate the associations of predicted methylation with PC risk. For associated CpGs, we compared their measured levels in pancreatic tumor vs benign tissue. Results We identified 45 CpGs at nine loci showing an association with PC risk, including 15 CpGs showing an association independent from identified risk variants. We observed significant correlations between predicted methylation of 16 of the 45 CpGs and predicted expression of eight adjacent genes, of which six genes showed associations with PC risk. Of the 45 CpGs, we were able to compare measured methylation of 16 in pancreatic tumor versus benign pancreatic tissue. Of them, six showed differentiated methylation. Conclusions We identified methylation biomarker candidates associated with PC using genetic instruments and added additional insights into the role of methylation in regulating gene expression in PC development. Impact: A comprehensive study using genetic instruments identifies 45 CpG sites at nine genomic loci for PC risk.
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http://dx.doi.org/10.1158/1055-9965.EPI-21-0400DOI Listing
September 2021

Discovery of structural deletions in breast cancer predisposition genes using whole genome sequencing data from > 2000 women of African-ancestry.

Hum Genet 2021 Aug 27. Epub 2021 Aug 27.

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, TN, 37203-1738, Nashville, USA.

Single germline nucleotide pathogenic variants have been identified in 12 breast cancer predisposition genes, but structural deletions in these genes remain poorly characterized. We conducted in-depth whole genome sequencing (WGS) in genomic DNA samples obtained from 1340 invasive breast cancer cases and 675 controls of African ancestry. We identified 25 deletions in the intragenic regions of ten established breast cancer predisposition genes based on a consensus call from six state-of-the-art SV callers. Overall, no significant case-control difference was found in the frequency of these deletions. However, 1.0% of cases and 0.3% of controls carried any of the eight putative protein-truncating rare deletions located in BRCA1, BRCA2, CDH1, TP53, NF1, RAD51D, RAD51C and CHEK2, resulting in an odds ratio (OR) of 3.29 (95% CI 0.74-30.16). We also identified a low-frequency deletion in NF1 associated with breast cancer risk (OR 1.93, 95% CI 1.14-3.42). In addition, we detected 56 deletions, including six putative protein-truncating deletions, in suspected breast predisposition genes. This is the first large study to systematically search for structural deletions in breast cancer predisposition genes. Many of the deletions, particularly those resulting in protein truncations, are likely to be pathogenic. Results from this study, if confirmed in future large-scale studies, could have significant implications for genetic testing for this common cancer.
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http://dx.doi.org/10.1007/s00439-021-02342-8DOI Listing
August 2021

Association of oral microbiota with lung cancer risk in a low-income population in the Southeastern USA.

Cancer Causes Control 2021 Aug 25. Epub 2021 Aug 25.

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, 1161 21st Avenue South, Nashville, TN, USA.

Purpose: Oral microbiome plays an important role in oral health and systemic diseases, including cancer. We aimed to prospectively investigate the association of oral microbiome with lung cancer risk.

Methods: We analyzed 156 incident lung cancer cases (73 European Americans and 83 African Americans) and 156 individually matched controls nested within the Southern Community Cohort Study. Oral microbiota were assessed using 16S rRNA gene sequencing in pre-diagnostic mouth rinse samples. Paired t test and the permutational multivariate analysis of variance test were used to evaluate lung cancer risk association with alpha diversity or beta diversity, respectively. Conditional logistic regression models were used to evaluate the association of individual bacterial abundance or prevalence with lung cancer risk.

Results: No significant differences were observed for alpha or beta diversity between lung cancer cases and controls. Abundance of families Lachnospiraceae_[XIV], Peptostreptococcaceae_[XI], and Erysipelotrichaceae and species Parvimonas micra was associated with decreased lung cancer risk, with odds ratios (ORs) and 95% confidence intervals (CIs) of 0.76 (0.59-0.98), 0.80 (0.66-0.97), 0.81 (0.67-0.99), and 0.83 (0.71-0.98), respectively (all p < 0.05). Prevalence of five pre-defined oral pathogens were not significantly associated with overall lung cancer risk. Prevalence of genus Bacteroidetes_[G-5] and species Alloprevotella sp._oral_taxon_912, Capnocytophaga sputigena, Lactococcus lactis, Peptoniphilaceae_[G-1] sp._oral_taxon_113, Leptotrichia sp._oral_taxon_225, and Fretibacterium fastidiosum was associated with decreased lung cancer risk, with ORs and 95% CIs of 0.55 (0.30-1.00), 0.36 (0.17-0.73), 0.53 (0.31-0.92), 0.43 (0.21-0.88), 0.43 (0.19-0.94), 0.57 (0.34-0.99), and 0.54 (0.31-0.94), respectively (all p < 0.05). Species L. sp._oral_taxon_225 was significantly associated with decreased lung cancer risk in African Americans (OR [95% CIs] 0.28 [0.12-0.66]; p = 0.00012).

Conclusion: Results from this study suggest that oral microbiota may play a role in the development of lung cancer.
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http://dx.doi.org/10.1007/s10552-021-01490-6DOI Listing
August 2021

Functional annotation of the 2q35 breast cancer risk locus implicates a structural variant in influencing activity of a long-range enhancer element.

Am J Hum Genet 2021 07 18;108(7):1190-1203. Epub 2021 Jun 18.

Genomic Epidemiology Group, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany.

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).
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http://dx.doi.org/10.1016/j.ajhg.2021.05.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8322933PMC
July 2021

Legume Consumption and Gut Microbiome in Elderly Chinese Men and Women.

J Nutr 2021 Aug;151(8):2399-2408

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA.

Background: Legumes, important components of a healthy diet, may exert their health benefits through the influence of the gut microbiome. However, this hypothesis has not been well investigated.

Objective: This study aimed to examine the associations between long-term legume consumption and the gut microbiome among elderly Chinese.

Methods: The gut microbiome was profiled by 16S ribosomal RNA sequencing in 2302 Chinese adults enrolled in 2 large cohort studies, the Shanghai Women's Health Study and Shanghai Men's Health Study. Legume consumption, including peanuts, soy foods, and other beans, was assessed by food-frequency questionnaires prior to the stool collection. The associations of legume consumption with microbiome diversity and taxa abundance were evaluated by linear or negative binomial hurdle models, adjusting for sociodemographics, lifestyle factors, and BMI. False discovery rate (FDR)-corrected P values (PFDR) < 0.1 were considered significant.

Results: Respectively, 52% and 48% of study participants were male and female. The mean age at stool collection was 68.03 y for females and 70.28 y for males. Total legume consumption was not associated with gut microbiome ɑ-diversity; however, male peanut consumers had a higher Chao1 index (β = 22.52, P = 0.01), whereas peanut consumption was associated with decreased Shannon (β = -0.03, P = 0.02) and Simpson (β = -0.002, P = 0.04) indexes among females. In female and male combined analyses, total legume consumption was associated with increased Enterobacteriales (β = 0.30, PFDR = 0.06). Within this order, an unclassified genus in the family Enterobacteriaceae was positively associated with total legume (β = 0.46, PFDR = 0.03) and peanut (β = 0.59, PFDR = 0.01) consumption. Stratified analyses showed significant associations were primarily confined to females and participants without metabolic conditions.

Conclusions: Legume consumption was associated with gut microbiome diversity and abundance of some bacteria in elderly Chinese. Associations were significant only among 1 sex group. Further research, including large-scale prospective studies and feeding trials, is needed to fully understand the role of the gut microbiome in legume-health associations.
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http://dx.doi.org/10.1093/jn/nxab139DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8435997PMC
August 2021

The trans-ancestral genomic architecture of glycemic traits.

Nat Genet 2021 06 31;53(6):840-860. Epub 2021 May 31.

Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.

Glycemic traits are used to diagnose and monitor type 2 diabetes and cardiometabolic health. To date, most genetic studies of glycemic traits have focused on individuals of European ancestry. Here we aggregated genome-wide association studies comprising up to 281,416 individuals without diabetes (30% non-European ancestry) for whom fasting glucose, 2-h glucose after an oral glucose challenge, glycated hemoglobin and fasting insulin data were available. Trans-ancestry and single-ancestry meta-analyses identified 242 loci (99 novel; P < 5 × 10), 80% of which had no significant evidence of between-ancestry heterogeneity. Analyses restricted to individuals of European ancestry with equivalent sample size would have led to 24 fewer new loci. Compared with single-ancestry analyses, equivalent-sized trans-ancestry fine-mapping reduced the number of estimated variants in 99% credible sets by a median of 37.5%. Genomic-feature, gene-expression and gene-set analyses revealed distinct biological signatures for each trait, highlighting different underlying biological pathways. Our results increase our understanding of diabetes pathophysiology by using trans-ancestry studies for improved power and resolution.
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http://dx.doi.org/10.1038/s41588-021-00852-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7610958PMC
June 2021

Effects of Screenings in Reducing Colorectal Cancer Incidence and Mortality Differ by Polygenic Risk Scores.

Clin Transl Gastroenterol 2021 05 6;12(5):e00344. Epub 2021 May 6.

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA.

Introduction: Colorectal cancer (CRC) screening reduces CRC incidence and mortality. However, it is unclear whether the reduction in CRC risk may differ by genetic susceptibility.

Methods: We evaluated this question in a cohort of 304,740 participants of European descent aged 50 years and older. Genetic susceptibility was measured using a polygenic risk score (PRS) constructed with risk variants identified in genomewide association studies. Cox models were used to estimate hazard ratios and 95% confidence intervals of CRC risk.

Results: Over a median follow-up of 7.0 years, 2,261 incident CRC cases and 528 CRC deaths were identified. CRC screening was associated with a significantly reduced CRC incidence among individuals with a high (hazard ratio, 0.80; 95% confidence interval, 0.71-0.92) and intermediate PRS (0.84, 0.71-0.98) but not among those with a low PRS (1.03, 0.86-1.25; Pinteraction, 0.005). A similar but more evident difference was observed for mortality (Pinteraction, 0.046), with more than 30% reduced mortality observed in the high PRS group (0.69, 0.52-0.91). Among the younger group (age 50-60 years), CRC screenings were associated with a slightly (but nonsignificantly) elevated incidence and mortality in the low PRS group but a reduced risk in the high PRS group (Pinteraction, 0.043 [incidence]; 0.092 [mortality]). No significant interaction was observed in the older group (age > 60 years).

Discussion: Individuals with a higher genetic risk benefited more substantially from CRC screenings than those with a lower risk. Our findings suggest that PRS may be used to develop personalized CRC screening to maximize its effect on CRC prevention.
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http://dx.doi.org/10.14309/ctg.0000000000000344DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8104134PMC
May 2021

Long-term Diet Quality and Gut Microbiome Functionality: A Prospective, Shotgun Metagenomic Study among Urban Chinese Adults.

Curr Dev Nutr 2021 Apr 2;5(4):nzab026. Epub 2021 Apr 2.

Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.

Background: Diet is known to affect human gut microbiome composition; yet, how diet affects gut microbiome functionality remains unclear.

Objective: We compared the diversity and abundance/presence of fecal microbiome metabolic pathways among individuals according to their long-term diet quality.

Methods: In 2 longitudinal cohorts, we assessed participants' usual diets via repeated surveys during 1996-2011 and collected a stool sample in 2015-2018. Participants who maintained a healthy or unhealthy diet (i.e., stayed in the highest or lowest quintile of a healthy diet score throughout follow-up) were selected. Participants were excluded if they reported a history of cancer, cardiovascular disease, diabetes, or hypertension; had diarrhea or constipation in the last 7 d; or used antibiotics in the last 6 mo before stool collection. Functional profiling of shotgun metagenomics was performed using HUMAnN2. Associations of dietary variables and 420 microbial metabolic pathways were evaluated via multivariable-adjusted linear or logistic regression models.

Results: We included 144 adults (mean age = 64 y; 55% female); 66 had an unhealthy diet and 78 maintained a healthy diet. The healthy diet group had higher Shannon α-diversity indexes of microbial gene families and metabolic pathways (both < 0.02), whereas β-diversity, as evaluated by Bray-Curtis distance, did not differ between groups (both > 0.50). At < 0.01 [false discovery rate (FDR) <0.15], the healthy diet group showed enriched pathways for vitamin and carrier biosynthesis (e.g., tetrahydrofolate, acetyl-CoA, and l-methionine) and tricarboxylic acid (TCA) cycle, and increased degradation (or reduced biosynthesis) of certain sugars [e.g., cytidine monophosphate (CMP)-legionaminate, deoxythymidine diphosphate (dTDP)-l-rhamnose, and sucrose], nucleotides, 4-aminobutanoate, methylglyoxal, sulfate, and aromatic compounds (e.g., catechol and toluene). Meanwhile, several food groups were associated with the CMP-legionaminate biosynthesis pathway at FDR <0.05.

Conclusions: In a small longitudinal study of generally healthy, older Chinese adults, we found long-term healthy eating was associated with increased α-diversity of microbial gene families and metabolic pathways and altered symbiotic functions relevant to human nutrition and health.
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http://dx.doi.org/10.1093/cdn/nzab026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8068758PMC
April 2021

Associations between Genetically Predicted Circulating Protein Concentrations and Endometrial Cancer Risk.

Cancers (Basel) 2021 Apr 26;13(9). Epub 2021 Apr 26.

Population Sciences in the Pacific Program, Cancer Epidemiology Division, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, HI 96813, USA.

Endometrial cancer (EC) is the leading female reproductive tract malignancy in developed countries. Currently, genome-wide association studies (GWAS) have identified 17 risk loci for EC. To identify novel EC-associated proteins, we used previously reported protein quantitative trait loci for 1434 plasma proteins as instruments to evaluate associations between genetically predicted circulating protein concentrations and EC risk. We studied 12,906 cases and 108,979 controls of European descent included in the Endometrial Cancer Association Consortium, the Epidemiology of Endometrial Cancer Consortium, and the UK Biobank. We observed associations between genetically predicted concentrations of nine proteins and EC risk at a false discovery rate of <0.05 (-values range from 1.14 × 10 to 3.04 × 10). Except for vascular cell adhesion protein 1, all other identified proteins were independent from known EC risk variants identified in EC GWAS. The respective odds ratios (95% confidence intervals) per one standard deviation increase in genetically predicted circulating protein concentrations were 1.21 (1.13, 1.30) for DNA repair protein RAD51 homolog 4, 1.27 (1.14, 1.42) for desmoglein-2, 1.14 (1.07, 1.22) for MHC class I polypeptide-related sequence B, 1.05 (1.02, 1.08) for histo-blood group ABO system transferase, 0.77 (0.68, 0.89) for intestinal-type alkaline phosphatase, 0.82 (0.74, 0.91) for carbohydrate sulfotransferase 15, 1.07 (1.03, 1.11) for D-glucuronyl C5-epimerase, and 1.07 (1.03, 1.10) for CD209 antigen. In conclusion, we identified nine potential EC-associated proteins. If validated by additional studies, our findings may contribute to understanding the pathogenesis of endometrial tumor development and identifying women at high risk of EC along with other EC risk factors and biomarkers.
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http://dx.doi.org/10.3390/cancers13092088DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8123478PMC
April 2021

Functional Genomic Analyses of the 21q22.3 Locus Identifying Functional Variants and Candidate Gene for Breast Cancer Risk.

Cancers (Basel) 2021 Apr 23;13(9). Epub 2021 Apr 23.

Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN 37203, USA.

We previously identified a locus at 21q22.3, tagged by the single nucleotide polymorphism (SNP) rs35418111, being associated with breast cancer risk at a genome-wide significance level; however, the underlying causal functional variants and gene(s) responsible for this association are unknown. We performed functional genomic analyses to identify potential functional variants and target genes that may mediate this association. Functional annotation for SNPs in high linkage disequilibrium (LD, r > 0.8) with rs35418111 in Asians showed evidence of promoter and/or enhancer activities, including rs35418111, rs2078203, rs8134832, rs57385578, and rs8126917. These five variants were assessed for interactions with nuclear proteins by electrophoretic mobility shift assays. Our results showed that the risk alleles for rs2078203 and rs35418111 altered DNA-protein interaction patterns. Cis-expression quantitative loci (cis-eQTL) analysis, using data from the Genotype-Tissue Expression database (GTEx) European-ancestry female normal breast tissue, indicated that the risk allele of rs35418111 was associated with a decreased expression of the gene, a relatively uncharacterized endoribonuclease in humans. We investigated the biological effects of on breast cancer cell lines by transient knock-down of expression in MCF-7, T47D, and MDA-MB-231 cell lines. Knockdown of mRNA in breast cancer cell lines consistently decreased cell proliferation, colony formation, and migration/invasion, regardless of estrogen receptor status. We performed RNA sequencing in MDA-MB-231 cells transfected with siRNA targeting and subsequent gene set enrichment analysis to identify gene networks associated with knockdown. These data indicated was involved in networks associated with inflammation and metabolism. Finally, we showed trends in expression patterns in breast tissues from The Cancer Genome Atlas (TCGA); early-stage breast cancers had elevated expression compared with normal tissue, but significantly decreased expression in late-stage disease. Our study provides evidence of a significant role for the human gene in breast cancer pathogenesis and the association between the rs35418111/21q22.3 locus and breast cancer risk, which may be mediated through functional SNPs, rs35418111 and rs2078203, that regulate expression of .
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http://dx.doi.org/10.3390/cancers13092037DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8122893PMC
April 2021

Incorporating European GWAS findings improve polygenic risk prediction accuracy of breast cancer among East Asians.

Genet Epidemiol 2021 Jul 19;45(5):471-484. Epub 2021 Mar 19.

Department of Molecular Physiology & Biophysics, Vanderbilt Genetics Institute, Vanderbilt University, Nashville, Tennessee, USA.

Previous genome-wide association studies (GWASs) have been largely focused on European (EUR) populations. However, polygenic risk scores (PRSs) derived from EUR have been shown to perform worse in non-EURs compared with EURs. In this study, we aim to improve PRS prediction in East Asians (EASs). We introduce a rescaled meta-analysis framework to combine both EUR (N = 122,175) and EAS (N = 30,801) GWAS summary statistics. To improve PRS prediction in EASs, we use a scaling factor to up-weight the EAS data, such that the resulting effect size estimates are more relevant to EASs. We then derive PRSs for EAS from the rescaled meta-analysis results of EAS and EUR data. Evaluated in an independent EAS validation data set, this approach increases the prediction liability-adjusted Nagelkerke's pseudo R by 40%, 41%, and 5%, respectively, compared with PRSs derived from an EAS GWAS only, EUR GWAS only, and conventional fixed-effects meta-analysis of EAS and EUR data. The PRS derived from the rescaled meta-analysis approach achieved an area under the receiver operating characteristic curve (AUC) of 0.6059, higher than AUC = 0.5782, 0.5809, 0.6008 for EAS, EUR, and conventional meta-analysis of EAS and EUR. We further compare PRSs constructed by single-nucleotide polymorphisms that have different linkage disequilibrium (LD) scores and minor allele frequencies (MAFs) between EUR and EAS, and observe that lower LD scores or MAF in EAS correspond to poorer PRS performance (AUC = 0.5677, 0.5530, respectively) than higher LD scores or MAF (AUC = 0.589, 0.5993, respectively). We finally build a PRS stratified by LD score differences in EUR and EAS using rescaled meta-analysis, and obtain an AUC of 0.6096, with improvement over other strategies investigated.
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http://dx.doi.org/10.1002/gepi.22382DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8372543PMC
July 2021

Multi-omics analysis to identify susceptibility genes for colorectal cancer.

Hum Mol Genet 2021 04;30(5):321-330

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37203, USA.

Most genetic variants for colorectal cancer (CRC) identified in genome-wide association studies (GWAS) are located in intergenic regions, implying pathogenic dysregulations of gene expression. However, comprehensive assessments of target genes in CRC remain to be explored. We conducted a multi-omics analysis using transcriptome and/or DNA methylation data from the Genotype-Tissue Expression, The Cancer Genome Atlas and the Colonomics projects. We identified 116 putative target genes for 45 GWAS-identified variants. Using summary-data-based Mendelian randomization approach (SMR), we demonstrated that the CRC susceptibility for 29 out of the 45 CRC variants may be mediated by cis-effects on gene regulation. At a cutoff of the Bonferroni-corrected PSMR < 0.05, we determined 66 putative susceptibility genes, including 39 genes that have not been previously reported. We further performed in vitro assays for two selected genes, DIP2B and SFMBT1, and provide functional evidence that they play a vital role in colorectal carcinogenesis via disrupting cell behavior, including migration, invasion and epithelial-mesenchymal transition. Our study reveals a large number of putative novel susceptibility genes and provides additional insight into the underlying mechanisms for CRC genetic risk loci.
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http://dx.doi.org/10.1093/hmg/ddab021DOI Listing
April 2021

Long-term diet quality is associated with gut microbiome diversity and composition among urban Chinese adults.

Am J Clin Nutr 2021 03;113(3):684-694

Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.

Background: Few population-based studies have evaluated the influence of long-term diet on the gut microbiome, and data among Asian populations are lacking.

Objective: We examined the association of long-term diet quality, comprising 8 food groups (fruit, vegetables, dairy, fish/seafood, nuts/legumes, refined grains, red meat, and processed meat), with gut microbiome among Chinese adults.

Methods: Included were 1920 men and women, enrolled in 2 prospective cohorts (baseline 1996-2006), who remained free of cardiovascular diseases, diabetes, and cancer at stool collection (2015-2018) and had no diarrhea or antibiotic use in the last 7 d before stool collection. Microbiome was profiled by 16S rRNA sequencing. Long-term diet was assessed by repeated surveys at baseline and follow-ups (1996-2011), with intervals of 5.2 to 20.5 y between dietary surveys and stool collection. Associations of dietary variables with microbiome diversity and composition were evaluated by linear or negative binomial hurdle models, adjusting for potential confounders. False discovery rate (FDR) <0.1 was considered significant.

Results: The mean ± SD age at stool collection was 68 ± 1.5 y. Diet quality was positively associated with microbiome α-diversity (P = 0.03) and abundance of Firmicutes, Actinobacteria, Tenericutes, and genera/species within these phyla, including Coprococcus, Faecalibacterium/Faecalibacterium prausnitzii, Bifidobacterium / Bifidobacterium adolescentis, and order RF39 (all FDRs <0.1). Significant associations were also observed for intakes of dairy, fish/seafood, nuts/legumes, refined grains, and processed meat, including a positive association of dairy with Bifidobacterium and inverse associations of processed meat with Roseburia /Roseburia faecis. Most associations were similar, with or without adjustment for BMI and hypertension status or excluding participants with antibiotic use in the past 6 mo.

Conclusion: Among apparently healthy Chinese adults, long-term diet quality is positively associated with fecal microbiome diversity and abundance of fiber-fermenting bacteria, although magnitudes are generally small. Future studies are needed to examine if these bacteria may mediate or modify diet-disease relations.
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http://dx.doi.org/10.1093/ajcn/nqaa350DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7948864PMC
March 2021

Association between ALDH2 and ADH1B Polymorphisms and the Risk for Colorectal Cancer in Koreans.

Cancer Res Treat 2021 Jul 24;53(3):754-762. Epub 2020 Dec 24.

Department of Preventive Medicine, Chonnam National University Medical School, Hwasun, Korea.

Purpose: Excessive alcohol consumption has been linked to an increased risk of colorectal cancer (CRC). We evaluated the association between alcohol-related genetic variants and CRC risk.

Materials And Methods: The study cohort consisted of 5,435 CRC cases and 3,553 population-based cancer-free controls. Genotype data were generated from germline DNA using the Infinium OncoArray-500K BeadChip in 2,535 cases and 2,287 controls and the Infinium Multi-Ethnic Global BeadChip in 2,900 cases and 1,266 controls. The associations between aldehyde dehydrogenase 2 (ALDH2) rs671 and alcohol dehydrogenase 1B (ADH1B) rs1229984 polymorphisms and CRC risk were assessed using multivariate logistic regression analyses.

Results: Compared with the major homozygous ALDH2 genotype (GG), heterozygous or minor homozygous ALDH2 genotype (GA or AA, related to a low alcohol consumption) was significantly associated with a reduced risk for CRC in men (odds ratio [OR], 0.78; 95% confidence interval [CI], 0.68 to 0.90), but not in women (OR, 0.70; 95% CI, 0.47 to 1.05). A stronger association was found among regular drinkers (OR, 0.58; 95% CI, 0.47 to 0.71 in men and OR, 0.33; 95% CI, 0.18 to 0.58 in women). No association of CRC risk with ADH1B rs1229984 genotype was found. The association between alcohol-related combined genotypes and risk of CRC was significant (p for linear=0.001). The combined genotype with the highest genetically predicted alcohol consumption (ALDH2 rs671 GG and ADH1B rs1229984 AG/GG) was associated with a high risk for CRC (OR, 1.35; 95% CI, 1.11 to 1.63).

Conclusion: Our study provides strong evidence for a possible causal association between alcohol consumption and CRC risk.
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http://dx.doi.org/10.4143/crt.2020.478DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8291179PMC
July 2021

Variation in oral microbiome is associated with future risk of lung cancer among never-smokers.

Thorax 2021 03 14;76(3):256-263. Epub 2020 Dec 14.

National Cancer Institute, Bethesda, Maryland, USA.

Objective: To prospectively investigate whether diversity in oral microbiota is associated with risk of lung cancer among never-smokers.

Design And Setting: A nested case-control study within two prospective cohort studies, the Shanghai Women's Health Study (n=74 941) and the Shanghai Men's Health Study (n=61 480).

Participants: Lifetime never-smokers who had no cancer at baseline. Cases were subjects who were diagnosed with incident lung cancer (n=114) and were matched 1:1 with controls on sex, age (≤2 years), date (≤30 days) and time (morning/afternoon) of sample collection, antibiotic use during the week before sample collection (yes/no) and menopausal status (for women).

Main Outcomes And Measures: Metagenomic shotgun sequencing was used to measure the community structure and abundance of the oral microbiome in pre-diagnostic oral rinse samples of each case and control. Multivariable logistic regression models were used to estimate the association of lung cancer risk with alpha diversity metrics and relative abundance of taxa. The Microbiome Regression-Based Kernel Association Test (MiRKAT) evaluated the association between risk and the microbiome beta diversity.

Results: Subjects with lower microbiota alpha diversity had an increased risk of lung cancer compared with those with higher microbial alpha diversity (Shannon: p=0.05; Simpson: p=0.04; Observed Species: p=0.64). No case-control differences were apparent for beta diversity (p=0.30). After accounting for multiple comparisons, a greater abundance of Spirochaetia (OR 1.00 (reference), OR 0.61 (95% CI 0.32 to 1.18), OR 0.42 (95% CI 0.21 to 0.85)) and Bacteroidetes (OR 1.00 (reference), OR 0.66 (95% CI 0.35 to 1.25), OR 0.31 (95% CI 0.15 to 0.64)) was associated with a decreased risk of lung cancer, while a greater abundance of the Bacilli class (OR 1.00 (reference), OR 1.49 (95% CI 0.73 to 3.08), OR 2.40 (95% CI 1.18 to 4.87)) and Lactobacillales order (OR 1.00 (reference), OR 2.15 (95% CI 1.03 to 4.47), OR 3.26 (95% CI 1.58 to 6.70)) was associated with an increased risk of lung cancer.

Conclusions: Our prospective study of never-smokers suggests that lower alpha diversity was associated with a greater risk of lung cancer and the abundance of certain specific taxa was associated with altered risk, providing further insight into the aetiology of lung cancer in the absence of active tobacco smoking.
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http://dx.doi.org/10.1136/thoraxjnl-2020-215542DOI Listing
March 2021

Identifying Novel Susceptibility Genes for Colorectal Cancer Risk From a Transcriptome-Wide Association Study of 125,478 Subjects.

Gastroenterology 2021 03 12;160(4):1164-1178.e6. Epub 2020 Oct 12.

Department of Cancer Biology and Genetics and the Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio.

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, 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.
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http://dx.doi.org/10.1053/j.gastro.2020.08.062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7956223PMC
March 2021

Mendelian Randomization Analysis of n-6 Polyunsaturated Fatty Acid Levels and Pancreatic Cancer Risk.

Cancer Epidemiol Biomarkers Prev 2020 12 23;29(12):2735-2739. Epub 2020 Sep 23.

Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts.

Background: Whether circulating polyunsaturated fatty acid (PUFA) levels are associated with pancreatic cancer risk is uncertain. Mendelian randomization (MR) represents a study design using genetic instruments to better characterize the relationship between exposure and outcome.

Methods: We utilized data from genome-wide association studies within the Pancreatic Cancer Cohort Consortium and Pancreatic Cancer Case-Control Consortium, involving approximately 9,269 cases and 12,530 controls of European descent, to evaluate associations between pancreatic cancer risk and genetically predicted plasma n-6 PUFA levels. Conventional MR analyses were performed using individual-level and summary-level data.

Results: Using genetic instruments, we did not find evidence of associations between genetically predicted plasma n-6 PUFA levels and pancreatic cancer risk [estimates per one SD increase in each PUFA-specific weighted genetic score using summary statistics: linoleic acid odds ratio (OR) = 1.00, 95% confidence interval (CI) = 0.98-1.02; arachidonic acid OR = 1.00, 95% CI = 0.99-1.01; and dihomo-gamma-linolenic acid OR = 0.95, 95% CI = 0.87-1.02]. The OR estimates remained virtually unchanged after adjustment for covariates, using individual-level data or summary statistics, or stratification by age and sex.

Conclusions: Our results suggest that variations of genetically determined plasma n-6 PUFA levels are not associated with pancreatic cancer risk.

Impact: These results suggest that modifying n-6 PUFA levels through food sources or supplementation may not influence risk of pancreatic cancer.
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http://dx.doi.org/10.1158/1055-9965.EPI-20-0651DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710600PMC
December 2020

From tobacco smoking to cancer mutational signature: a mediation analysis strategy to explore the role of epigenetic changes.

BMC Cancer 2020 Sep 14;20(1):880. Epub 2020 Sep 14.

Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, 37203, USA.

Background: Tobacco smoking is associated with a unique mutational signature in the human cancer genome. It is unclear whether tobacco smoking-altered DNA methylations and gene expressions affect smoking-related mutational signature.

Methods: We systematically analyzed the smoking-related DNA methylation sites reported from five previous casecontrol studies in peripheral blood cells to identify possible target genes. Using the mediation analysis approach, we evaluated whether the association of tobacco smoking with mutational signature is mediated through altered DNA methylation and expression of these target genes in lung adenocarcinoma tumor tissues.

Results: Based on data obtained from 21,108 blood samples, we identified 374 smoking-related DNA methylation sites, annotated to 248 target genes. Using data from DNA methylations, gene expressions and smoking-related mutational signature generated from ~ 7700 tumor tissue samples across 26 cancer types from The Cancer Genome Atlas (TCGA), we found 11 of the 248 target genes whose expressions were associated with smoking-related mutational signature at a Bonferroni-correction P < 0.001. This included four for head and neck cancer, and seven for lung adenocarcinoma. In lung adenocarcinoma, our results showed that smoking increased the expression of three genes, AHRR, GPR15, and HDGF, and decreased the expression of two genes, CAPN8, and RPS6KA1, which were consequently associated with increased smoking-related mutational signature. Additional evidence showed that the elevated expression of AHRR and GPR15 were associated with smoking-altered hypomethylations at cg14817490 and cg19859270, respectively, in lung adenocarcinoma tumor tissues. Lastly, we showed that decreased expression of RPS6KA1, were associated with poor survival of lung cancer patients.

Conclusions: Our findings provide novel insight into the contributions of tobacco smoking to carcinogenesis through the underlying mechanisms of the elevated mutational signature by altered DNA methylations and gene expressions.
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http://dx.doi.org/10.1186/s12885-020-07368-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7488848PMC
September 2020

Mendelian randomization analyses suggest a role for cholesterol in the development of endometrial cancer.

Int J Cancer 2021 01 7;148(2):307-319. Epub 2020 Aug 7.

Behavioral and Epidemiology Research Group, American Cancer Society, Atlanta, Georgia, USA.

Blood lipids have been associated with the development of a range of cancers, including breast, lung and colorectal cancer. For endometrial cancer, observational studies have reported inconsistent associations between blood lipids and cancer risk. To reduce biases from unmeasured confounding, we performed a bidirectional, two-sample Mendelian randomization analysis to investigate the relationship between levels of three blood lipids (low-density lipoprotein [LDL] and high-density lipoprotein [HDL] cholesterol, and triglycerides) and endometrial cancer risk. Genetic variants associated with each of these blood lipid levels (P < 5 × 10 ) were identified as instrumental variables, and assessed using genome-wide association study data from the Endometrial Cancer Association Consortium (12 906 cases and 108 979 controls) and the Global Lipids Genetic Consortium (n = 188 578). Mendelian randomization analyses found genetically raised LDL cholesterol levels to be associated with lower risks of endometrial cancer of all histologies combined, and of endometrioid and non-endometrioid subtypes. Conversely, higher genetically predicted HDL cholesterol levels were associated with increased risk of non-endometrioid endometrial cancer. After accounting for the potential confounding role of obesity (as measured by genetic variants associated with body mass index), the association between genetically predicted increased LDL cholesterol levels and lower endometrial cancer risk remained significant, especially for non-endometrioid endometrial cancer. There was no evidence to support a role for triglycerides in endometrial cancer development. Our study supports a role for LDL and HDL cholesterol in the development of non-endometrioid endometrial cancer. Further studies are required to understand the mechanisms underlying these findings.
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http://dx.doi.org/10.1002/ijc.33206DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7757859PMC
January 2021

An integrative multi-omics analysis to identify candidate DNA methylation biomarkers related to prostate cancer risk.

Nat Commun 2020 08 6;11(1):3905. Epub 2020 Aug 6.

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA.

It remains elusive whether some of the associations identified in genome-wide association studies of prostate cancer (PrCa) may be due to regulatory effects of genetic variants on CpG sites, which may further influence expression of PrCa target genes. To search for CpG sites associated with PrCa risk, here we establish genetic models to predict methylation (N = 1,595) and conduct association analyses with PrCa risk (79,194 cases and 61,112 controls). We identify 759 CpG sites showing an association, including 15 located at novel loci. Among those 759 CpG sites, methylation of 42 is associated with expression of 28 adjacent genes. Among 22 genes, 18 show an association with PrCa risk. Overall, 25 CpG sites show consistent association directions for the methylation-gene expression-PrCa pathway. We identify DNA methylation biomarkers associated with PrCa, and our findings suggest that specific CpG sites may influence PrCa via regulating expression of candidate PrCa target genes.
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http://dx.doi.org/10.1038/s41467-020-17673-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7413371PMC
August 2020

Fecal metagenomics and metabolomics reveal gut microbial changes after bariatric surgery.

Surg Obes Relat Dis 2020 Nov 27;16(11):1772-1782. Epub 2020 Jun 27.

Division of General Surgery, Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee.

Background: Evidence from longitudinal patient studies regarding gut microbial changes after bariatric surgery is limited.

Objective: To examine intraindividual changes in fecal microbiome and metabolites among patients undergoing Roux-en-Y gastric bypass or vertical sleeve gastrectomy.

Setting: Observational study.

Methods: Twenty patients were enrolled and provided stool samples before and 1 week, 1 month, and/or 3 months after surgery. Shallow shotgun metagenomics and untargeted fecal metabolomics were performed. Zero-inflated generalized additive models and linear mixed models were applied to identify fecal microbiome and metabolites changes, with adjustment for potential confounders and correction for multiple testing.

Results: We enrolled 16 women and 4 men, including 16 white and 4 black participants (median age = 45 years; presurgery body mass index = 47.7 kg/m). Ten patients had Roux-en-Y gastric bypass, 10 had vertical sleeve gastrectomy, and 14 patients provided postsurgery stool samples. Of 47 samples, median sequencing depth was 6.3 million reads and 1073 metabolites were identified. Microbiome alpha-diversity increased after surgery, especially at 3 months. Significant genus-level changes included increases in Odoribacter, Streptococcus, Anaerotruncus, Alistipes, Klebsiella, and Bifidobacterium, while decreases in Bacteroides, Coprocosccus, Dorea, and Faecalibacterium. Large increases in Streptococcus, Akkermansia, and Prevotella were observed at 3 months. Beta-diversity and fecal metabolites were also changed, including reduced caffeine metabolites, indoles, and butyrate.

Conclusions: Despite small sample size and missing repeated samples in some participants, our pilot study showed significant postsurgery changes in fecal microbiome and metabolites among bariatric surgery patients. Future large-scale, longitudinal studies are warranted to investigate gut microbial changes and their associations with metabolic outcomes after bariatric surgery.
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http://dx.doi.org/10.1016/j.soard.2020.06.032DOI Listing
November 2020

Evaluating the Utility of Polygenic Risk Scores in Identifying High-Risk Individuals for Eight Common Cancers.

JNCI Cancer Spectr 2020 Jun 12;4(3):pkaa021. Epub 2020 Mar 12.

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA.

Background: Genome-wide association studies have identified common genetic risk variants in many loci associated with multiple cancers. We sought to systematically evaluate the utility of these risk variants in identifying high-risk individuals for eight common cancers.

Methods: We constructed polygenic risk scores (PRS) using genome-wide association studies-identified risk variants for each cancer. Using data from 400 812 participants of European descent in a population-based cohort study, UK Biobank, we estimated hazard ratios associated with PRS using Cox proportional hazard models and evaluated the performance of the PRS in cancer risk prediction and their ability to identify individuals at more than a twofold elevated risk, a risk level comparable to a moderate-penetrance mutation in known cancer predisposition genes.

Results: During a median follow-up of 5.8 years, 14 584 incident case patients of cancers were identified (ranging from 358 epithelial ovarian cancer case patients to 4430 prostate cancer case patients). Compared with those at an average risk, individuals among the highest 5% of the PRS had a two- to threefold elevated risk for cancer of the prostate, breast, pancreas, colorectal, or ovary, and an approximately 1.5-fold elevated risk of cancer of the lung, bladder, or kidney. The areas under the curve ranged from 0.567 to 0.662. Using PRS, 40.4% of the study participants can be classified as having more than a twofold elevated risk for at least one site-specific cancer.

Conclusions: A large proportion of the general population can be identified at an elevated cancer risk by PRS, supporting the potential clinical utility of PRS for personalized cancer risk prediction.
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http://dx.doi.org/10.1093/jncics/pkaa021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7306192PMC
June 2020

Evaluating polygenic risk scores in assessing risk of nine solid and hematologic cancers in European descendants.

Int J Cancer 2020 12 9;147(12):3416-3423. Epub 2020 Jul 9.

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA.

Genome-wide association studies (GWAS) have identified many genetic risk variants for cancers. The utility of these variants in assessing risk of esophageal, gastric and endometrial cancers, as well as melanoma, glioma, diffuse large B-cell lymphoma, follicular lymphoma, chronic lymphoid leukemia and multiple myeloma, has not been adequately investigated. We constructed a site-specific polygenic risk score (PRS) for each of these nine cancers using their GWAS-identified risk variants. Using data from 400 807 participants of European descent in the UK Biobank, a population-based cohort study, we estimated the hazard ratios of each cancer associated with its PRS using Cox proportional hazard models. During a median follow-up of 5.8 years, 3905 incident cases of these nine cancers were identified in the cohort. The area under the receiver operating characteristic curve ranged from 0.53 to 0.69 for these cancers. Except for esophageal cancer, significant dose-response associations were observed between PRS and cancer risk. Compared to individuals in the middle quintile (40%-60%) at an average risk, those among the highest 5% of the PRS had a twofold elevated risk of melanoma, glioma, follicular lymphoma or multiple myeloma, and a fourfold elevated risk of chronic lymphoid leukemia. Using PRS, 63.0% of the participants could be classified as having an over twofold elevated risk for at least one cancer. The PRS derived using risk variants identified to date by GWAS showed the potential in identifying individuals at a significantly elevated risk of cancer for prevention.
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http://dx.doi.org/10.1002/ijc.33176DOI Listing
December 2020

Differences in gene-expression profiles in breast cancer between African and European-ancestry women.

Carcinogenesis 2020 07;41(7):1015

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center.

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http://dx.doi.org/10.1093/carcin/bgaa041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7359761PMC
July 2020

Identification of type 2 diabetes loci in 433,540 East Asian individuals.

Nature 2020 06 6;582(7811):240-245. Epub 2020 May 6.

Vanderbilt Genetics Institute, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.

Meta-analyses of genome-wide association studies (GWAS) have identified more than 240 loci that are associated with type 2 diabetes (T2D); however, most of these loci have been identified in analyses of individuals with European ancestry. Here, to examine T2D risk in East Asian individuals, we carried out a meta-analysis of GWAS data from 77,418 individuals with T2D and 356,122 healthy control individuals. In the main analysis, we identified 301 distinct association signals at 183 loci, and across T2D association models with and without consideration of body mass index and sex, we identified 61 loci that are newly implicated in predisposition to T2D. Common variants associated with T2D in both East Asian and European populations exhibited strongly correlated effect sizes. Previously undescribed associations include signals in or near GDAP1, PTF1A, SIX3, ALDH2, a microRNA cluster, and genes that affect the differentiation of muscle and adipose cells. At another locus, expression quantitative trait loci at two overlapping T2D signals affect two genes-NKX6-3 and ANK1-in different tissues. Association studies in diverse populations identify additional loci and elucidate disease-associated genes, biology, and pathways.
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http://dx.doi.org/10.1038/s41586-020-2263-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7292783PMC
June 2020

Associations between Genetically Predicted Blood Protein Biomarkers and Pancreatic Cancer Risk.

Cancer Epidemiol Biomarkers Prev 2020 07 21;29(7):1501-1508. Epub 2020 May 21.

Department of Health Sciences Research, Mayo Clinic College of Medicine, Rochester, Minnesota.

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, with few known risk factors and biomarkers. Several blood protein biomarkers have been linked to PDAC in previous studies, but these studies have assessed only a limited number of biomarkers, usually in small samples. In this study, we evaluated associations of circulating protein levels and PDAC risk using genetic instruments.

Methods: To identify novel circulating protein biomarkers of PDAC, we studied 8,280 cases and 6,728 controls of European descent from the Pancreatic Cancer Cohort Consortium and the Pancreatic Cancer Case-Control Consortium, using genetic instruments of protein quantitative trait loci.

Results: We observed associations between predicted concentrations of 38 proteins and PDAC risk at an FDR of < 0.05, including 23 of those proteins that showed an association even after Bonferroni correction. These include the protein encoded by , which has been implicated as a potential target gene of PDAC risk variant. Eight of the identified proteins (LMA2L, TM11D, IP-10, ADH1B, STOM, TENC1, DOCK9, and CRBB2) were associated with PDAC risk after adjusting for previously reported PDAC risk variants (OR ranged from 0.79 to 1.52). Pathway enrichment analysis showed that the encoding genes for implicated proteins were significantly enriched in cancer-related pathways, such as STAT3 and IL15 production.

Conclusions: We identified 38 candidates of protein biomarkers for PDAC risk.

Impact: This study identifies novel protein biomarker candidates for PDAC, which if validated by additional studies, may contribute to the etiologic understanding of PDAC development.
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http://dx.doi.org/10.1158/1055-9965.EPI-20-0091DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7334065PMC
July 2020

Evaluation of pathogenetic mutations in breast cancer predisposition genes in population-based studies conducted among Chinese women.

Breast Cancer Res Treat 2020 Jun 21;181(2):465-473. Epub 2020 Apr 21.

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, USA.

Purpose: Limited studies have been conducted to evaluate pathogenetic mutations in breast cancer predisposition genes among Chinese women. To fully characterize germline mutations of these genes in this population, we used the whole-exome sequencing data in a population-based case-control study conducted in Shanghai, China.

Methods: We evaluated exonic, splicing, and copy number variants in 11 established and 14 candidate breast cancer predisposition genes in 831 invasive breast cancer cases and 839 controls. We identified 55 pathogenic variants, including 15 newly identified in this study.

Results: Approximately 8% of the cases and 0.6% of the cancer-free controls carried these pathogenetic variants (P = 3.05 × 10). Among cases, 3.7% had a BRCA2 pathogenic variant and 1.6% had a BRCA1 pathogenic variant, while 2.5% had a pathogenic variant in other genes including ATM, CHEK2, NBN, NF1, CDH1, PALB2, PTEN, TP53 as well as BARD1, BRIP, and RAD51D. Patients with BRCA1/2 pathogenic variants were more likely to have a family history of breast cancer and hormone receptor negative tumors compared with patients without pathogenic variants.

Conclusions: This study highlighted the importance of hereditary breast cancer genes in the breast cancer etiology in this understudied population. Together with previous studies in East Asian women, this study suggested a relatively more prominent role of BRCA2 compared to BRCA1. This study also provides additional evidence to design cost-efficient genetic testing among Chinese women for risk assessment and early detection of breast cancer.
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http://dx.doi.org/10.1007/s10549-020-05643-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7188717PMC
June 2020

Differences in gene-expression profiles in breast cancer between African and European-ancestry women.

Carcinogenesis 2020 07;41(7):887-893

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center and Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA.

African American (AA) women have an excess breast cancer mortality than European American (EA) women. To investigate the contribution of tumor biology to this survival health disparity, we compared gene expression profiles in breast tumors using RNA sequencing data derived from 260 AA and 155 EA women who were prospectively enrolled in the Southern Community Cohort Study (SCCS) and developed breast cancer during follow-up. We identified 59 genes (54 protein-coding genes and 5 long intergenic non-coding RNAs) that were expressed differently between EA and AA at a stringent false discovery rate (FDR) < 0.01. A gene signature was derived with these 59 genes and externally validated using the publicly available Cancer Genome Atlas (TCGA) data from180 AA and 838 EA breast cancer patients. Applying C-statistics, we found that this 59-gene signature has a high discriminative ability in distinguishing AA and EA breast cancer patients in the TCGA dataset (C-index = 0.81). These findings may provide new insight into tumor biological differences and the causes of the survival disparity between AA and EA breast cancer patients.
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http://dx.doi.org/10.1093/carcin/bgaa035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7359770PMC
July 2020

Reply to Kenyon, "Are Differences in the Oral Microbiome Due to Ancestry or Socioeconomics?"

mSystems 2020 Mar 10;5(2). Epub 2020 Mar 10.

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA

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http://dx.doi.org/10.1128/mSystems.00891-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7065519PMC
March 2020
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