Publications by authors named "Abkevich V"

Purpose: Polygenic risk scores (PRSs) for breast cancer (BC) risk stratification have been developed primarily in women of European ancestry. Their application to women of non-European ancestry has lagged because of the lack of a formal approach to incorporate genetic ancestry and ancestry-dependent variant frequencies and effect sizes. Here, we propose a multiple-ancestry PRS (MA-PRS) that addresses these issues and may be useful in the development of equitable PRSs across other cancers and common diseases.

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  • The study investigates how defects in the homologous recombination (HR) DNA repair pathway impact the effectiveness of standard neoadjuvant chemotherapy in triple-negative breast cancer (TNBC) and BRCA1/2 mutation-associated cases.
  • Researchers analyzed tumor samples from 45 TNBC patients to determine HR deficiency status using HRD scores and BRCA1/2 mutation status, assessing their responses through residual cancer burden (RCB) index.
  • Results showed that HR deficient patients had a significantly higher likelihood of achieving a pathologic complete response (pCR) to chemotherapy compared to non-deficient patients, indicating the importance of HR status in guiding treatment decisions.
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  • BRCA1/2 mutations and some sporadic triple-negative breast cancers (TNBC) are sensitive to DNA-damaging treatments due to DNA repair defects, and new genomic instability measures have been developed.
  • A combined homologous recombination deficiency (HRD) score, based on loss of heterozygosity (LOH), telomeric allelic imbalance (TAI), and large-scale state transitions (LST), was evaluated in neoadjuvant TNBC trials with platinum therapy to predict treatment response.
  • Results indicate that HR deficiency significantly predicts positive treatment outcomes, such as low residual cancer burden and complete response, even in BRCA1/2 non-mutated tumors, suggesting HR deficiency is a reliable biomarker
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The purpose of this study is to evaluate the efficacy and safety of neoadjuvant treatment with carboplatin and eribulin in patients with early-stage triple negative breast cancer (TNBC), and to explore biomarkers based on DNA and protein expression profiles as predictors of response. Patients with histologically confirmed early-stage TNBC received carboplatin AUC 6 iv every 21 days, and eribulin 1.4 mg/m(2) day 1 and day 8 every 21 days for four cycles.

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  • - The study evaluated the effectiveness and safety of iniparib combined with gemcitabine and carboplatin in treating early-stage triple-negative and BRCA1/2 mutation-associated breast cancer.
  • - Involved 80 patients, with a 36% overall pathologic complete response rate, indicating a significant impact of the treatment.
  • - The results revealed that patients with higher homologous recombination deficiency (HRD-LOH) scores had better responses, suggesting HRD-LOH could help identify effective treatment candidates even among those without BRCA mutations.
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Introduction: Homologous recombination (HR) DNA repair is of clinical relevance in breast cancer. Three DNA-based homologous recombination deficiency (HRD) scores (HRD-loss of heterozygosity score (LOH), HRD-telomeric allelic imbalance score (TAI), and HRD-large-scale state transition score (LST)) have been developed that are highly correlated with defects in BRCA1/2, and are associated with response to platinum therapy in triple negative breast and ovarian cancer. This study examines the frequency of BRCA1/2 defects among different breast cancer subtypes, and the ability of the HRD scores to identify breast tumors with defects in the homologous recombination DNA repair pathway.

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Background: Defects in BRCA1, BRCA2, and other members of the homologous recombination pathway have potential therapeutic relevance when used to support agents that introduce or exploit double-stranded DNA breaks. This study examines the association between homologous recombination defects and genomic patterns of loss of heterozygosity (LOH).

Methods: Ovarian tumours from two independent data sets were characterised for defects in BRCA1, BRCA2, and RAD51C, and LOH profiles were generated.

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Human esophageal adenocarcinoma (EAC) cell lines and xenografts are powerful tools in the search for genetic alterations because these models are composed of pure human cancer cell populations without admixture of normal human cells. In particular detection of homozygous deletions (HDs) is easier using these pure populations of cancer cells. Identification of HDs could potentially lead to the subsequent identification of new tumor suppressor genes (TSGs) involved in esophageal adenocarcinogenesis.

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Genomic copy number variations are a typical feature of cancer. These variations may influence cancer outcomes as well as effectiveness of treatment. There are many computational methods developed to detect regions with deletions and amplifications without estimating actual copy numbers (CN) in these regions.

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Purpose: The prevalence of BRCA(1/2) mutations in germline DNA from unselected ovarian cancer patients is 11% to 15.3%. It is important to determine the frequency of somatic BRCA(1/2) changes, given the sensitivity of BRCA-mutated cancers to poly (ADP ribose) polymerase-1 (PARP1) inhibitors and platinum analogs.

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Linkage analysis on Utah pedigrees with strong family histories of major depression including only cases with the SLC6A4 HTTLPR short allele revealed a linkage peak on chromosome 4 (maximum HLOD = 3.5). This evidence suggests epistasis between SLC6A4 and an unknown gene as risk factors for major depression.

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Osteoarthritis (OA), the most prevalent form of arthritis in the elderly, is characterized by the degradation of articular cartilage and has a strong genetic component. Our aim was to identify genetic variants involved in risk of knee OA in women. A pooled genome-wide association scan with the Illumina550 Duo array was performed in 255 controls and 387 cases.

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Psoriasis is an immune-mediated skin disorder that is inherited as a multifactorial trait. Linkage studies have clearly identified a primary disease susceptibility locus lying within the major histocompatibility complex (MHC), but have generated conflicting results for other genomic regions. To overcome this difficulty, we have carried out a genome-wide association scan, where we analyzed more than 408,000 SNPs in an initial sample of 318 cases and 288 controls.

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The HTR1A -1019C>G genotype was associated with major depression in the Utah population. Linkage analysis on Utah pedigrees with strong family histories of major depression including only cases with the HTR1A -1019G allele revealed a linkage peak on chromosome 10 (maximum HLOD=4.4).

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Objective: Recently, separate genome-wide association analyses have identified nonsynonymous SNPs in IL23R and ATG16L1 (rs11209026; c1142G>A, R381Q, and rs2241880; c1338A>G, T300A, respectively) as strong candidate susceptibility factors for Crohn's disease (CD) in whites. The aim of our study was to test whether these SNPs are associated with CD in a population-based cohort of New Zealand Caucasian inflammatory bowel disease (IBD) patients.

Methods: Allele frequencies of rs11209026 and rs2241880 were determined in 496 CD patients, 466 ulcerative colitis (UC) patients, and 591 controls.

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Objective: The objective was to provide an overall assessment of genetic linkage data of BMI and BMI-defined obesity using a nonparametric genome scan meta-analysis.

Research Methods And Procedures: We identified 37 published studies containing data on over 31,000 individuals from more than >10,000 families and obtained genome-wide logarithm of the odds (LOD) scores, non-parametric linkage (NPL) scores, or maximum likelihood scores (MLS). BMI was analyzed in a pooled set of all studies, as a subgroup of 10 studies that used BMI-defined obesity, and for subgroups ascertained through type 2 diabetes, hypertension, or subjects of European ancestry.

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Context: The melanin-concentrating hormone receptor 2 (MCHR2) is a G protein-coupled receptor for melanin-concentrating hormone, a neuropeptide that plays an important role in feeding behaviors. MCHR2 maps on chromosome 6q16.3, in a susceptibility locus for childhood obesity.

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A pragmatic approach that balances the benefit of a whole-genome association (WGA) experiment against the cost of individual genotyping is to use pooled genomic DNA samples. We aimed to determine the feasibility of this approach in a WGA scan in rheumatoid arthritis (RA) using the validated human leucocyte antigen (HLA) and PTPN22 associations as test loci. A total of 203 269 single-nucleotide polymorphisms (SNPs) on the Affymetrix 100K GeneChip and Illumina Infinium microarrays were examined.

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The molecular etiology of obesity predisposition is largely unknown. Here, we present evidence that genetic variation in TBC1D1 confers risk for severe obesity in females. We identified a coding variant (R125W) in TBC1D1 that segregated with the disease in 4p15-14-linked obesity pedigrees.

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APAF1, encoding the protein apoptosis protease activating factor 1 (Apaf-1), has recently been established as a chromosome 12 gene conferring predisposition to major depression in humans. The molecular phenotypes of Apaf-1 variants were determined by in vitro reconstruction of the apoptosome complex in which Apaf-1 activates caspase 9 and thus initiates a cascade of proteolytic events leading to apoptotic destruction of the cell. Cellular phenotypes were measured using a yeast heterologous expression assay in which human Apaf-1 and other proteins necessary to constitute a functional apoptotic pathway were overexpressed.

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Major depressive disorder (MDD) is a common, clinically heterogeneous disorder often found comorbid with other disorders. We studied recurrent, early-onset MDD (MDD-RE) and anxiety disorders in combination to define powerful phenotypes for genetic study. We used 87 large, extended Utah pedigrees to investigate linkage to 3 phenotypes: "MDD-RE;" "MDD-RE or anxiety;" and "MDD-RE and anxiety;" where in the latter definition the disorders must appear comorbid within an individual.

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Introduction: Interpretation of results from mutation screening of tumour suppressor genes known to harbour high risk susceptibility mutations, such as APC, BRCA1, BRCA2, MLH1, MSH2, TP53, and PTEN, is becoming an increasingly important part of clinical practice. Interpretation of truncating mutations, gene rearrangements, and obvious splice junction mutations, is generally straightforward. However, classification of missense variants often presents a difficult problem.

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Major depression disorder is a common psychiatric disease with a major economic impact on society. In many cases, no effective treatment is available. The etiology of major depression is complex, but it is clear that the disease is, to a large extent, determined genetically, especially among individuals with a familial history of major depression, presumably through the involvement of multiple predisposition genes in addition to an environmental component.

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Epidemiological studies have shown an association of decreased serum bilirubin levels with coronary artery disease. Two segregation analyses in large pedigrees have suggested a major gene responsible for high bilirubin levels occurring in about 12% of the population. Based on a recessive model from a previous segregation analysis, we performed a genome scan using 587 markers genotyped in 862 individuals from 48 Utah pedigrees to detect loci linked to high bilirubin levels.

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