Publications by authors named "Mitchell J Machiela"

Glyphosate-based herbicides are the most widely applied pesticides worldwide and have been implicated in the development of certain hematologic malignancies; however, the underlying biological mechanisms are not well-understood. High lifetime use of glyphosate-based herbicides, hereafter referred to as glyphosate, was previously associated with mosaic loss of chromosome Y (mLOY), a biomarker of genomic instability potentially linked to cancer and immune dysregulation, in circulating blood of male farmers from a subcohort of the Agricultural Health Study (AHS). Here, we further investigated the association between glyphosate use and mLOY using buccal-derived DNA among 1,868 male pesticide applicators in an independent AHS study.

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Obesity has been associated with non-Hodgkin lymphoma (NHL), but the evidence is inconclusive. We examined the association between genetically determined adiposity and four common NHL subtypes: diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, chronic lymphocytic leukemia, and marginal zone lymphoma, using eight genome-wide association studies of European ancestry (N = 10,629 cases, 9505 controls) and constructing polygenic scores for body mass index (BMI), waist-to-hip ratio (WHR), and waist-to-hip ratio adjusted for BMI (WHRadjBMI). Higher genetically determined BMI was associated with an increased risk of DLBCL [odds ratio (OR) per standard deviation (SD) = 1.

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BACKGROUNDTelomere biology disorders (TBDs) exhibit incomplete penetrance and variable expressivity, even among individuals harboring the same pathogenic variant. We assessed whether common genetic variants associated with telomere length combine with large-effect variants to impact penetrance and expressivity in TBDs.METHODSWe constructed polygenic scores (PGS) for telomere length in the UK Biobank to quantify common variant burden and assessed the PGS distribution across patient cohorts and biobanks to determine whether individuals with severe TBD presentations have increased polygenic burden causing short telomeres.

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Genome-wide association studies (GWASs) of melanoma risk have identified 68 independent signals at 54 loci. For most loci, specific functional variants and their respective target genes remain to be established. Capture-HiC is an assay that links fine-mapped risk variants to candidate target genes by comprehensively mapping chromatin interactions.

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Unlabelled: Both acquired mutations and germline genetic variation are known risk factors for chronic lymphocytic leukemia (CLL). The joint characterization of germline, acquired, and clinical risk has the potential to improve CLL risk prediction. In this study, we investigated whether the inclusion of a CLL-associated polygenic score (PGS) and two common types of clonal hematopoiesis (CH), autosomal mosaic chromosomal alterations (mCA) and CH of indeterminate potential (CHIP), could improve CLL risk stratification in 436,784 participants in the UK Biobank and a replication set of 35,382 participants in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.

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Background: Organochlorine (OC) insecticides are a class of environmentally persistent chemicals linked to risk of several cancers, including non-Hodgkin lymphoma and prostate cancer. In vitro and animal studies suggest some OCs may be genotoxic, but evidence in humans is limited. Mosaic loss of the Y chromosome (mLOY) is a marker of genotoxicity and genomic instability that has been associated with certain cancers and may reflect intermediate effects of pesticide exposure.

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Self-identified race and ethnicity (SIRE) and genetic ancestry (GA) are potentially associated with disparities in health outcomes; however, independent effects of SIRE and GA on mortality in cancer survivors including when adjusting for multiple risk factors are understudied. Among 23,445 cancer survivors in the Prostate, Lung, Colorectal, and Ovarian Screening Trial, SIRE was associated with mortality among prostate, colorectal, lung, ovarian, and breast cancer survivors; GA was associated with mortality among prostate, colorectal, and breast cancer survivors. Associations were strong when adjusting for age at cancer diagnosis, sex, and tumor characteristics, but attenuated when adjusting for individual-level factors and population-level socioeconomic status.

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Previous epidemiological studies have reported increased risks of certain cancers in relation to pesticide exposures. Although the biologic mechanisms underlying these associations are not well understood, altered telomere length has been hypothesized to play a role. We examined associations between occupational use of specific pesticides and leukocyte telomere length in the Biomarkers of Exposure and Effect in Agriculture study, a molecular epidemiological investigation of pesticide applicators in Iowa and North Carolina.

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The chromosome 5p15.33 region, which encodes telomerase reverse transcriptase (TERT), harbors multiple germline variants identified by genome-wide association studies (GWAS) as risk for some cancers but protective for others. Here, we characterize a variable number tandem repeat within TERT intron 6, VNTR6-1 (38-bp repeat unit), and detect a strong link between VNTR6-1 alleles (Short: 24-27 repeats, Long: 40.

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We conducted a multiancestry genome-wide association study of prostate-specific antigen (PSA) levels in 296,754 men (211,342 European ancestry, 58,236 African ancestry, 23,546 Hispanic/Latino and 3,630 Asian ancestry; 96.5% of participants were from the Million Veteran Program). We identified 318 independent genome-wide significant (P ≤ 5 × 10) variants, 184 of which were novel.

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Obesity strongly increases the risk of cardiometabolic diseases, yet the underlying mediators of this relationship are not fully understood. Given that obesity strongly influences circulating protein levels, we investigated proteins mediating the effects of obesity on coronary artery disease, stroke and type 2 diabetes. By integrating two-step proteome-wide Mendelian randomization, colocalization, epigenomics and single-cell RNA sequencing, we identified five mediators and prioritized collagen type VI α3 (COL6A3).

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Mosaic loss of Y (mLOY) is the most common somatic chromosomal alteration detected in human blood. The presence of mLOY is associated with altered blood cell counts and increased risk of Alzheimer disease, solid tumors, and other age-related diseases. We sought to gain a better understanding of genetic drivers and associated phenotypes of mLOY through analyses of whole-genome sequencing (WGS) of a large set of genetically diverse males from the Trans-Omics for Precision Medicine (TOPMed) program.

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Genome-wide association studies (GWAS) of melanoma risk have identified 68 independent signals at 54 loci. For most loci, specific functional variants and their respective target genes remain to be established. Capture-HiC is an assay that links fine-mapped risk variants to candidate target genes by comprehensively mapping cell-type specific chromatin interactions.

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The chromosome 5p15.33 region, which encodes telomerase reverse transcriptase (TERT), harbors multiple germline variants identified by genome-wide association studies (GWAS) as risk for some cancers but protective for others. We characterized a variable number tandem repeat within intron 6 (VNTR6-1, 38-bp repeat unit) and observed a strong association between VNTR6-1 alleles (Short: 24-27 repeats, Long: 40.

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Deletion of the long q arm of chromosome 22 (22qDEL) is the most frequently identified recurrent somatic copy number alteration observed in papillary thyroid carcinoma (PTC). Since its role in PTC is not fully understood, we conducted a pooled analysis of genomic characteristics and clinical correlates in 1094 primary tumors from four published PTC genomic studies. The majority of PTC cases with 22qDEL exhibited arm-level loss of heterozygosity (86%); nearly all PTC cases with 22qDEL had losses in 22q12 and 13, which together constitute 70% of the q arm.

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Background: Mosaic loss of chromosome Y (mLOY) in leukocytes of men reflects genomic instability from aging, smoking, and environmental exposures. A similar mosaic loss of chromosome X (mLOX) occurs among women. However, the associations between mLOY, mLOX, and risk of incident heart diseases are unclear.

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Background: Risk factors including smoking, alcohol intake, physical activity (PA), and sleep patterns have been associated with cancer risk. Clonal hematopoiesis (CH), including mosaic chromosomal alterations and clonal hematopoiesis of indeterminate potential, is linked to increased hematopoietic cancer risk and could be used as common preclinical intermediates for the better understanding of associations of risk factors with rare hematologic malignancies.

Methods: We analyzed cross-sectional data from 478,513 UK Biobank participants without hematologic malignancies using multivariable-adjusted analyses to assess the associations between lifestyle factors and CH types.

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We performed a series of integrative analyses including transcriptome-wide association studies (TWASs) and proteome-wide association studies (PWASs) of renal cell carcinoma (RCC) to nominate and prioritize molecular targets for laboratory investigation. On the basis of a genome-wide association study (GWAS) of 29,020 affected individuals and 835,670 control individuals and prediction models trained in transcriptomic reference models, our TWAS across four kidney transcriptomes (GTEx kidney cortex, kidney tubules, TCGA-KIRC [The Cancer Genome Atlas kidney renal clear-cell carcinoma], and TCGA-KIRP [TCGA kidney renal papillary cell carcinoma]) identified 38 gene associations (false-discovery rate <5%) in at least two of four transcriptomic panels and identified 12 genes that were independent of GWAS susceptibility regions. Analyses combining TWAS associations across 48 tissues from GTEx identified associations that were replicable in tumor transcriptomes for 23 additional genes.

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Article Synopsis
  • * The newly developed multi-ancestry PRS showed a strong correlation with LUAD risk, indicating that individuals in the highest PRS percentile had significantly increased risk compared to those in the lowest.
  • * Findings suggest that those in the highest risk category have a lifetime risk of about 6.69%, and they reach the average population's 10-year risk for LUAD by age 41, highlighting the importance of multi-ancestry PRS for better risk assessment in this group.
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Background: Mosaic loss of chromosome Y (mLOY) in leukocytes of men reflects genomic instability from aging, smoking, and environmental exposures. A similar mosaic loss of chromosome X (mLOX) occurs among women. However, the associations between mLOY, mLOX, and risk of incident heart diseases are unclear.

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Article Synopsis
  • Childhood exposure to radioactive iodine from the Chornobyl accident increases the risk of papillary thyroid carcinoma (PTC), particularly in younger individuals.
  • A study of 428 PTC cases found that cervical lymph node metastases (cLNM) were more common in PTC with certain genetic fusions compared to mutations, and this frequency varied significantly by specific gene types.
  • Molecular profiling of the cLNM showed strong genetic concordance with primary PTCs and identified 17 differentially expressed genes, pointing to potential biological mechanisms in PTC metastasis that require further investigation.
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