Publications by authors named "Dowty J"

Article Synopsis
  • - DNA methylation is an important epigenetic mechanism that regulates gene expression, and DNMT inhibitors are used extensively in research to study this process.
  • - Researchers developed a CRISPR-based method called SAM-DNMT3A that unexpectedly induces global DNA methylation, regardless of the specific DNA target.
  • - This approach reveals a potential therapeutic vulnerability in ER-positive breast cancer and emphasizes the need for careful use of CRISPR technology in methylation studies.
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  • Further research on identified regions could enhance our understanding of genetic risks for glioma.
  • The study indicates that sex might influence genetic susceptibility to glioma.
  • It emphasizes the need for future glioma studies to consider sex-specific factors in their analyses.*
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Differentially methylated CpG sites (dmCpGs) that distinguish prostate tumour from adjacent benign tissue could aid in the diagnosis and prognosis of prostate cancer. Previously, the identification of such dmCpGs has only been undertaken in radical prostatectomy (RP) samples and not primary diagnostic tumour samples (needle biopsy or transurethral resection of the prostate). We interrogated an Australian dataset comprising 125 tumour and 43 adjacent histologically benign diagnostic tissue samples, including 41 paired samples, using the Infinium Human Methylation450 BeadChip.

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Importance: Approximately 1% to 3% of gastric cancers and 5% of lobular breast cancers are hereditary. Loss of function CDH1 gene variants are the most common gene variants associated with hereditary diffuse gastric cancer and lobular breast cancer. Previously, the lifetime risk of gastric cancer was estimated to be approximately 25% to 83% and for breast cancer it was estimated to be approximately 39% to 55% in individuals with loss of function CDH1 gene variants.

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Young breast and bowel cancers (e.g., those diagnosed before age 40 or 50 years) have far greater morbidity and mortality in terms of years of life lost, and are increasing in incidence, but have been less studied.

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Article Synopsis
  • A polygenic risk score (PRS) evaluates the impact of multiple genetic variants on disease risk but may reflect familial confounding rather than direct causation.
  • New methods, ICE FALCON and ICE CRISTAL, analyze family data to determine the causal relationship of PRSs with breast cancer, showing differing results based on the age of diagnosis.
  • Findings indicate no causal link for younger patients (<50 years), while older patients exhibit evidence of causation, suggesting that genetic variants may not directly cause breast cancer but can be related to other familial or nongenetic factors.
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Background: Cirrus is an automated risk predictor for breast cancer that comprises texture-based mammographic features and is mostly independent of mammographic density. We investigated genetic and environmental variance of variation in Cirrus.

Methods: We measured Cirrus for 3,195 breast cancer-free participants, including 527 pairs of monozygotic (MZ) twins, 271 pairs of dizygotic (DZ) twins, and 1,599 siblings of twins.

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Background: Mammogram risk scores based on texture and density defined by different brightness thresholds are associated with breast cancer risk differently and could reveal distinct information about breast cancer risk. We aimed to investigate causal relationships between these intercorrelated mammogram risk scores to determine their relevance to breast cancer aetiology.

Methods: We used digitised mammograms for 371 monozygotic twin pairs, aged 40-70 years without a prior diagnosis of breast cancer at the time of mammography, from the Australian Mammographic Density Twins and Sisters Study.

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Article Synopsis
  • The text discusses how known and unknown factors contribute to differences in disease risk among individuals of the same age, particularly focusing on familial aspects of risk, both genetic and non-genetic.
  • A new model called VALID is introduced, which helps quantify the variance in risk by analyzing correlations between family members and transforming familial risk ratios into components of risk.
  • The application of VALID in female breast cancer demonstrates that, despite identifying significant genetic risk factors, there remains a considerable gap in understanding genetic and familial influences, especially in younger women.
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Background: A risk-stratified approach to colorectal cancer (CRC) screening could result in a more acceptable balance of benefits and harms, and be more cost-effective.

Aim: To determine the effect of a consultation in general practice using a computerised risk assessment and decision support tool (Colorectal cancer RISk Prediction, CRISP) on risk-appropriate CRC screening.

Design And Setting: Randomised controlled trial in 10 general practices in Melbourne, Australia, from May 2017 to May 2018.

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Background: Birt-Hogg-Dubé (BHD) syndrome is a rare genetic syndrome caused by pathogenic or likely pathogenic germline variants in the gene. Patients with BHD syndrome have an increased risk of fibrofolliculomas, pulmonary cysts, pneumothorax and renal cell carcinoma. There is debate regarding whether colonic polyps should be added to the criteria.

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DNA methylation marks that are inherited from parents to offspring are known to play a role in cancer risk and could explain part of the familial risk for cancer. We therefore conducted a genome-wide search for heritable methylation marks associated with prostate cancer risk. Peripheral blood DNA methylation was measured for 133 of the 469 members of 25 multiple-case prostate cancer families, using the EPIC array.

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Genetic counseling plays a critical role in supporting individuals and their families' adaption to psychiatric conditions, addressing the multifactorial nature of these conditions in a personally meaningful and empowering way. Yet data related to the practice and attitudes of Australian genetic counselors about psychiatric genetic counseling (PGC) is limited. This survey investigated the practice of Australian genetic counselors, and their attitudes toward PGC.

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Article Synopsis
  • - The study aims to compare colorectal cancer (CRC) incidences between two groups: one group receiving mandatory colonoscopy surveillance (PLSD) and another group with retrospective data (IMRC) that did not have the same follow-up.
  • - Results from the PLSD showed higher CRC rates in carriers of MMR gene variants, particularly for path_MLH1 and path_MSH2, compared to the IMRC cohort, challenging previous expectations about cancer rates in these groups.
  • - The study concludes that while colonoscopy did reduce CRC incidences in paths_MPS2 carriers prior to age 50, it did not have the same effect for path_MLH1 and path_MSH2, suggesting the need for reevaluation of
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Germline mutations in are associated with aggressive prostate cancer. Additional information regarding the clinical phenotype of germline pathogenic variants in other prostate cancer predisposition genes is required. Clinical testing has been limited by evidence, further restricting knowledge of variants that contribute to prostate cancer development.

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Cumulus, Altocumulus, and Cirrocumulus are measures of mammographic density defined at increasing pixel brightness thresholds, which, when converted to mammogram risk scores (MRSs), predict breast cancer risk. Twin and family studies suggest substantial variance in the MRSs could be explained by genetic factors. For 2559 women aged 30 to 80 years (mean 54 years), we measured the MRSs from digitized film mammograms and estimated the associations of the MRSs with a 313-SNP breast cancer polygenic risk score (PRS) and 202 individual SNPs associated with breast cancer risk.

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Article Synopsis
  • The study examines the role of the ATM gene in breast cancer risk through a multigene panel test applied to the Australian Breast Cancer Family Registry (ABCFR).
  • It found that carriers of pathogenic ATM variants have a breast cancer hazard ratio of 1.32, with a cumulative risk of 13% by age 80.
  • The conclusion emphasizes the need for more specific data on variant penetrance to improve management strategies for individuals with these genetic variants.
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Objectives: Maternal adversity during pregnancy has been shown to be associated with some health outcomes in the offspring. This study investigated the association of maternal adversity during pregnancy and DNA methylation with offspring cardiovascular (CV) health.

Design: Longitudinal observational cohort study SETTING: All pregnant residents in county Avon (∼0.

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, , , and are mammogram risk scores (MRSs) for breast cancer based on mammographic density defined in effect by different levels of pixel brightness and adjusted for age and body mass index. We measured these MRS from digitized film mammograms for 593 monozygotic (MZ) and 326 dizygotic (DZ) female twin pairs and 1592 of their sisters. We estimated the correlations in relatives () and the proportion of variance due to genetic factors (heritability) using the software FISHER and predicted the familial risk ratio (FRR) associated with each MRS.

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Article Synopsis
  • The study emphasizes the need for population-based estimates of breast cancer risk for women carrying pathogenic variants found through gene-panel testing, moving beyond high-risk selections.
  • Researchers tested 2,326 women (1,464 diagnosed with breast cancer and 862 controls) and 6,549 older healthy women for rare genetic variants to assess breast cancer risk.
  • The results revealed that certain gene variants, such as BRCA1 and BRCA2, significantly increased breast cancer risk, highlighting the importance of improving identification methods for women at risk.
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Objective: In previous studies using Illumina Infinium methylation arrays, we have identified DNA methylation marks associated with cancer predisposition and progression. In the present study, we have sought to find appropriate technology to both technically validate our data and expand our understanding of DNA methylation in these genomic regions. Here, we aimed to assess the repeatability of methylation measures made using QIAseq targeted methyl panel and to compare them with those obtained from the Illumina HumanMethylation450 (HM450K) assay.

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While gene panel sequencing is becoming widely used for cancer risk prediction, its clinical utility with respect to predicting aggressive prostate cancer (PrCa) is limited by our current understanding of the genetic risk factors associated with predisposition to this potentially lethal disease phenotype. This study included 837 men diagnosed with aggressive PrCa and 7261 controls (unaffected men and men who did not meet criteria for aggressive PrCa). Rare germline pathogenic variants (including likely pathogenic variants) were identified by targeted sequencing of 26 known or putative cancer predisposition genes.

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Article Synopsis
  • Case-control studies indicate that pathogenic variants are linked to a 3-fold increased risk of breast cancer, primarily due to the variant c.1100delC.
  • A population-based study involving 26 families and 1071 relatives estimated the hazard ratio for carriers of pathogenic variants at 4.9 compared to non-carriers, with specific ratios of 3.5 for c.1100delC and 5.7 for other variants.
  • The age-specific cumulative risk of breast cancer was found to be 18% by age 60 and 33% by age 80, offering valuable insights for managing breast cancer risk in women with pathogenic variants.
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is a metastable epiallele with accumulating evidence that methylation at this region is heritable, modifiable and associated with disease including risk and progression of cancer. This study investigated the influence of genetic variation and other factors such as age and adult lifestyle on blood DNA methylation in this region. We first sequenced the gene region in multiple-case breast cancer families in which methylation was identified as heritable and associated with breast cancer risk.

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Mammograms contain information that predicts breast cancer risk. We developed two novel mammogram-based breast cancer risk measures based on image brightness (Cirrocumulus) and texture (Cirrus). Their risk prediction when fitted together, and with an established measure of conventional mammographic density (Cumulus), is not known.

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