Ancestral Informative Markers Research Articles

386 The Analysis of N-glycans and Collagen to Predict Prostate Adenocarcinoma Outcome

OBJECTIVES/GOALS: Distinguishing indolent from aggressive prostate cancer and early identification of men at risk of developing aggressive, metastatic disease is of great importance. We aim to explore the relationship between N-glycan and collagen composition in prostate tumor tissue and the long-term outcome of the disease. METHODS/STUDY POPULATION: Matrix assisted laser desorption/ionization mass spectrometry can be utilized to characterize N-glycan profiles in formalin fixed paraffin embedded tissues. Collagen may also be characterized using ECM-targeted collagenase MALDI imaging. These approaches were used to analyze prostatectomy samples with different clinical outcomes. Tissue microarrays containing tissues from 75 non-progressors (no evidence of disease; NED) and 50 metastatic cases (MET) were examined. From a combined list of 90 N-glycans and 500 collagenase peptides, the average AUC intensity value for each glycan and collagen peptide was extracted and assessed as a predictor of metastatic progression. Ancestral informative markers were analyzed and polygenic hazard risk scores were generated for samples as well. RESULTS/ANTICIPATED RESULTS: Three N-glycans and three collagen peptides were found to discriminate between NED and MET cases with statistical significance. The best performing N-glycan was Hex6HexNAc6Fuc1 with an AUC of 0.77 (p<0.001). While the best performing collagen peptide was COL1A2 with an AUC of C 0.77 (p<0.001). DISCUSSION/SIGNIFICANCE: Both a collagen peptide and N-glycan were discovered as promising biomarkers to predict metastasis. Future validation studies are needed to confirm biomarker potential and to determine if the addition of these biomarkers can strengthen current genomic classifier’s ability to predict metastatic prostate cancer.

Abstract NG03: Multiomics in disparities research: Identifying African ancestry-specific mechanisms in the triple negative breast cancer tumor microenvironment

Abstract NG03: Multiomics in disparities research: Identifying African ancestry-specific mechanisms in the triple negative breast cancer tumor microenvironment

Global Distribution of Founder Variants Associated with Non-Syndromic Hearing Impairment.

The genetic etiology of non-syndromic hearing impairment (NSHI) is highly heterogeneous with over 124 distinct genes identified. The wide spectrum of implicated genes has challenged the implementation of molecular diagnosis with equal clinical validity in all settings. Differential frequencies of allelic variants in the most common NSHI causal gene, gap junction beta 2 (GJB2), has been described as stemming from the segregation of a founder variant and/or spontaneous germline variant hot spots. We aimed to systematically review the global distribution and provenance of founder variants associated with NSHI. The study protocol was registered on PROSPERO, the International Prospective Register of Systematic Reviews, with the registration number "CRD42020198573". Data from 52 reports, involving 27,959 study participants from 24 countries, reporting 56 founder pathogenic or likely pathogenic (P/LP) variants in 14 genes (GJB2, GJB6, GSDME, TMC1, TMIE, TMPRSS3, KCNQ4, PJVK, OTOF, EYA4, MYO15A, PDZD7, CLDN14, and CDH23), were reviewed. Varied number short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs) were used for haplotype analysis to identify the shared ancestral informative markers in a linkage disequilibrium and variants' origins, age estimates, and common ancestry computations in the reviewed reports. Asia recorded the highest number of NSHI founder variants (85.7%; 48/56), with variants in all 14 genes, followed by Europe (16.1%; 9/56). GJB2 had the highest number of ethnic-specific P/LP founder variants. This review reports on the global distribution of NSHI founder variants and relates their evolution to population migration history, bottleneck events, and demographic changes in populations linked with the early evolution of deleterious founder alleles. International migration and regional and cultural intermarriage, coupled to rapid population growth, may have contributed to re-shaping the genetic architecture and structural dynamics of populations segregating these pathogenic founder variants. We have highlighted and showed the paucity of data on hearing impairment (HI) variants in Africa, establishing unexplored opportunities in genetic traits.

Hereditary Cancer Gene Variants in Hispanic Men With a Personal or Family History of Prostate Cancer.

Mutations in several common hereditary cancer genes are associated with prostate cancer, but there is limited information on the prevalence of these mutations in Hispanic men. We selected men at high risk for genetic mutations from 1515 Hispanic men enrolled in the San Antonio Biomarkers of Risk for prostate cancer (SABOR) cohort. Inclusion criteria included men with a diagnosis of prostate cancer or a first-degree family history of prostate cancer. We performed germline genetic testing using the Color Genomics platform, sequencing 30 genes associated with hereditary cancer risk. Additionally, we assessed ancestral informative markers to determine the admixture of the ethnically unique cohort. Of the 275 subjects who met selection criteria, 263 patients had sufficient samples for sequencing. We identified 3.8% of patients (10 of 263) with a pathogenic or likely pathogenic mutation in the 30 genes tested, of whom 70% would not have met established criteria for genetic testing. Six of these mutations were in BRCA1/2 or ATM. There was a significant inverse association between the percentage of Native American ancestry and the risk of prostate cancer, OR 0.11 (95% CI 0.02-0.76, P=.025). Hispanic men with either a personal or family history of prostate cancer carry mutations in hereditary cancer genes at a significant rate, on par with non-Hispanic counterparts with similar risk factors.

Admixture mapping of anthropometric traits in the Black Women's Health Study: evidence of a shared African ancestry component with birth weight and type 2 diabetes.

Prevalence of obesity, type 2 diabetes (T2D), and being born with low birth weight are much higher in African American women compared to U.S. white women. Genetic factors may contribute to the excess risk of these conditions. We conducted admixture mapping of body mass index (BMI) at age 18, adult BMI, and adult waist circumference and waist-to-hip ratio adjusted for BMI using 2918 ancestral informative markers in 2596 participants of the Black Women's Health Study. We also searched for evidence of shared African genetic ancestry components among the four examined anthropometric traits and among birth weight and T2D. We found that global percent African ancestry was associated with higher adult BMI. We also found that African ancestry at 9q34 was associated with lower BMI at age 18. Our shared ancestry analysis identified ten genomic regions with local African ancestry associated with multiple traits. Seven out of these ten genomic loci were related to T2D risk. Of special interest is the 12q14-21 region where local African ancestry was associated with low birth weight, low BMI, high BMI-adjusted waist-to-hip ratio, and high T2D risk. Findings in the 12q14-21 genomic locus are consistent with the fetal insulin hypothesis that postulates that low birth weight and T2D have a common genetic basis, and they support the hypothesis of a shared African genetic ancestry component linking low birth weight and T2D in African Americans. Future studies should identify the actual genetic variants responsible for the clustering of these conditions in African Americans.

Novel genotyping approaches to easily detect genomic admixture between the major Afrotropical malaria vector species, Anopheles coluzzii and An. gambiae.

The two most efficient and most recently radiated Afrotropical vectors of human malaria – Anopheles coluzzii and An. gambiae – are identified by single‐locus diagnostic PCR assays based on species‐specific markers in a 4 Mb region on chromosome‐X centromere. Inherently, these diagnostic assays cannot detect interspecific autosomal admixture shown to be extensive at the westernmost and easternmost extremes of the species range. The main aim of this study was to develop novel, easy‐to‐implement tools for genotyping An. coluzzii and An. gambiae‐specific ancestral informative markers (AIMs) identified from the Anopheles gambiae 1000 genomes (Ag1000G) project. First, we took advantage of this large set of data in order to develop a multilocus approach to genotype 26 AIMs on all chromosome arms valid across the species range. Second, we tested the multilocus assay on samples from Guinea Bissau, The Gambia and Senegal, three countries spanning the westernmost hybridization zone, where conventional species diagnostic is problematic due to the putative presence of a novel “hybrid form”. The multilocus assay was able to capture patterns of admixture reflecting those revealed by the whole set of AIMs and provided new original data on interspecific admixture in the region. Third, we developed an easy‐to‐use, cost‐effective PCR approach for genotyping two AIMs on chromosome‐3 among those included in the multilocus approach, opening the possibility for advanced identification of species and of admixed specimens during routine large scale entomological surveys, particularly, but not exclusively, at the extremes of the range, where WGS data highlighted unexpected autosomal admixture.

Ancestry prediction efficiency of the software GenoGeographer using a z-score method and the ancestry informative markers in the Precision ID Ancestry Panel

We compared the efficiency of the freely available software GenoGeographer that includes a z-score based analysis with that of a naïve method based on the maximal likelihoods of 164 of the 165 ancestral informative markers (AIM) that are included in the commercially available kit Precision ID Ancestry Panel from Thermo Fisher Scientific. The AIM profiles were obtained by investigations with the Precision ID Ancestry Panel in our laboratory and from SNP data in the literature and publically available databases. We established eight well-defined AIM reference population data sets from 3603 AIM profiles. Six reference populations with profiles from multiple populations (Sub-Saharan Africa, North Africa, Middle East, Europe, South/Central Asia, East Asia), and two populations with individuals with admixed ancestry (Somalia and Greenland). By means of GenoGeographer and naïve calculations of the maximal likelihoods, 566 AIM profiles from individuals that were not included in the reference populations and expected to belong to one of the eight reference populations were tested. An initial standard z-score based test with GenoGeographer demonstrated that 22.4% of the individuals could not be assigned to any of the reference populations. Among the remaining 77.6% of the individuals, 83.6% were assigned to the reference population that was concordant with the specified populations of origin of the individuals, 8.2% had ambiguous assignments because they could belong to both the specified population of origin and one or more of the other populations, and 8.2% were assigned to a reference population that was discordant from the specified population of origin. A naïve assignment based on the maximal likelihood resulted in 78.1% concordant and 21.9% discordant assignments. The results demonstrate that the z-score analysis with GenoGeographer can reduce the error rate with a factor of almost three compared with that of the naïve estimation based on the maximal likelihoods of the AIM profiles. The Precision ID Ancestry Panel is a useful kit for the assignment of ancestry of the eight investigated populations that included two admixed populations. More AIMs with better discrimination and more data on the distribution of AIMs in relevant populations are needed to improve the efficiency of genogeographic prediction with AIMs on a worldwide basis.

Admixture mapping and fine-mapping of type 2 diabetes susceptibility loci in African American women.

African American women are disproportionately affected by type 2 diabetes. Genetic factors may explain part of the excess risk. More than 100 genetic variants have been associated with risk of type 2 diabetes, but most studies have been conducted in white populations. Two genome-wide association studies (GWAS) in African Americans have identified three novel genetic variants only. We conducted admixture mapping using 2,918 ancestral informative markers in 2,632 cases of type 2 diabetes and 2,596 controls nested in the ongoing Black Women’s Health Study cohort, with the goal of identifying genomic loci with local African ancestry associated with type 2 diabetes. In addition, we performed replication analysis of 71 previously identified index SNPs, and fine-mapped those genetic loci to identify better or new genetic variants associated with type 2 diabetes in African Americans. We found that individual African ancestry was associated with higher risk of type 2 diabetes. In addition, we identified two genomic regions, 3q26 and 12q23, with excess of African ancestry associated with higher risk of type 2 diabetes. Lastly, we replicated 8 out of 71 index SNPs from previous GWAS, including, for the first time in African Americans, the X-linked rs5945326 SNP near the DUSP9 gene. In addition, our fine-mapping efforts suggest independent signals at five loci. Our detailed analysis identified two genomic regions associated with risk of type 2 diabetes, and showed that many genetic risk variants are shared across ancestries.

Amerindian ancestry and extended longevity in Nicoya, Costa Rica.

The aim of this study was to address the hypothesis that Amerindian ancestry is associated with extended longevity in the admixed population of Nicoya, Costa Rica. The Nicoya Peninsula of Costa Rica has been considered a "longevity island," particularly for males. We estimated Amerindian ancestry using 464 ancestral informative markers in 20 old Nicoyans aged ≥99 years, and 20 younger Nicoyans (60-65 years). We used logistic regression to estimate odds ratio (OR) and 95% confidence interval (CI) of the association of Amerindian ancestry and longevity. Older Nicoyans had higher Amerindian ancestry compared to younger Nicoyans (43.3% vs 36.0%, P = .04). Each 10% increase of Amerindian ancestry was associated with more than twice the odds of being long-lived (OR = 2.32, 95% CI = 1.03-5.25). To our knowledge, this is the first time that ancestry is implicated as a likely determinant of extended longevity. Amerindian-specific alleles may protect against early mortality. The identification of these protective alleles should be the focus of future studies.

The Interaction between Genetic Ancestry and Breast Cancer Risk Factors among Hispanic Women: The Breast Cancer Health Disparities Study.

Background: Hispanic women have lower breast cancer incidence rates than non-Hispanic white (NHW) women. To what extent genetic versus nongenetic factors account for this difference is unknown.Methods: Using logistic regression, we evaluated the interactive influences of established risk factors and ethnicity (self-identified and identified by ancestral informative markers) on breast cancer risk among 2,326 Hispanic and 1,854 NHW postmenopausal women from the United States and Mexico in the Breast Cancer Health Disparities Study.Results: The inverse association between the percentage of Native American (NA) ancestry and breast cancer risk was only slightly attenuated after adjusting for known risk factors [lowest versus highest quartile: odds ratio (OR) =1.39, 95% confidence interval (CI) = 1.00-1.92 among U.S. Hispanics; OR = 1.92 (95% CI, 1.29-2.86) among Mexican women]. The prevalence of several risk factors, as well as the associations with certain factors and breast cancer risk, differed according to genetic admixture. For example, higher body mass index (BMI) was associated with reduced risk among women with lower NA ancestry only [BMI <25 versus >30: OR = 0.65 (95% CI, 0.44-0.98) among U.S. Hispanics; OR = 0.53 (95% CI, 0.29-0.97) among Mexicans]. The average number of risk factors among cases was inversely related to the percentage of NA ancestry.Conclusions: The lower NA ancestry groups were more likely to have the established risk factors, with the exception of BMI. Although the majority of factors were associated with risk in the expected directions among all women, BMI had an inverse association among Hispanics with lower NA ancestry.Impact: These data suggest that the established risk factors are less relevant for breast cancer development among women with more NA ancestry. Cancer Epidemiol Biomarkers Prev; 26(5); 692-701. ©2016 AACR.

Evaluation of the Precision ID Ancestry Panel for crime case work: A SNP typing assay developed for typing of 165 ancestral informative markers

The application of massive parallel sequencing (MPS) methodologies in forensic genetics is promising and it is gradually being implemented in forensic genetic case work. One of the major advantages of these technologies is that several traditional electrophoresis assays can be combined into one single MPS assay. This reduces both the amount of sample used and the time of the investigations.This study assessed the utility of the Precision ID Ancestry Panel (Thermo Fisher Scientific, Waltham, USA) in forensic genetics. This assay was developed for the Ion Torrent PGM™ System and genotypes 165 ancestry informative SNPs. The performance of the assay and the accompanying software solution for ancestry inference was assessed by typing 142 Danes and 98 Somalis. Locus balance, heterozygote balance, and noise levels were calculated and future analysis criteria for crime case work were estimated. Overall, the Precision ID Ancestry Panel performed well, and only minor changes to the recommended protocol were implemented. Three out of the 165 loci (rs459920, rs7251928, and rs7722456) had consistently poor performance, mainly due to misalignment of homopolymeric stretches. We suggest that these loci should be excluded from the analyses.The different statistical methods for reporting ancestry in forensic genetic case work are discussed.

Associations between ALOX, COX, and CRP polymorphisms and breast cancer among Hispanic and non-Hispanic white women: The breast cancer health disparities study.

Chronic inflammation is suggested to be associated with specific cancer sites, including breast cancer. Recent research has focused on the roles of genes involved in the leukotriene/lipoxygenase and prostaglandin/cyclooxygenase pathways in breast cancer etiology. We hypothesized that genes in ALOX/COX pathways and CRP polymorphisms would be associated with breast cancer risk and mortality in our sample of Hispanic/Native American (NA) (1430 cases, 1599 controls) and non-Hispanic white (NHW) (2093 cases, 2610 controls) women. A total of 104 Ancestral Informative Markers was used to distinguish European and NA ancestry. The adaptive rank truncated product (ARTP) method was used to determine the significance of associations for each gene and the inflammation pathway with breast cancer risk and by NA ancestry. Overall, the pathway was associated with breast cancer risk (PARTP = 0.01). Two-way interactions with NA ancestry (P(adj) < 0.05) were observed for ALOX12 (rs2292350, rs2271316) and PTGS1 (rs10306194). We observed increases in breast cancer risk in stratified analyses by tertiles of polyunsaturated fat intake for ALOX12 polymorphisms; the largest increase in risk was among women in the highest tertile with ALOX12 rs9904779CC (Odds Ratio (OR), 1.49; 95% Confidence Interval (CI) 1.14-1.94, P(adj) = 0.01). In a sub-analysis stratified by NSAIDs use, two-way interactions with NSAIDs use were found for ALOX12 rs9904779 (P(adj) = 0.02), rs434473 (P(adj ) = 0.02), and rs1126667 (P(adj) = 0.01); ORs for ALOX12 polymorphisms ranged from 1.55 to 1.64 among regular users. Associations were not observed with breast cancer mortality. These findings could support advances in the discovery of new pathways related to inflammation for breast cancer treatment.

Admixture mapping of growth related traits in F2 mice dataset using ancestry informative markers

Most of the associated single nucleotide polymorphisms (SNPs) for genome wide association studies (GWAS) explain very little proportion of phenotypic variance in outbred populations. One reason is; large number of markers raises the problem of multiple hypothesis testing correction using conservative statistical tests in single marker models. Admixture mapping could be used as alternative model to detect the genes associated with quantitative traits by less number of ancestry informative markers. Ancestral genotypes of founder populations were available for the F₂ mice dataset for growth related traits. The objectives of this study were (1) to detect genomic signals by admixture mapping for growth related traits by ancestry informative markers and ancestral genotypes (2) to detect genomic signals for growth related traits by Bayes C(π) model and compare results with those obtained by use of admixture mapping. Bayes C(π) model detected more SNPs that has high ancestry informative markers. But due to stringent significance tests and small SNPs effects admixture model did not detect the same SNPs in Bayes C(π). As was expected higher ancestral informative markers lead to higher Z values in admixture model with a little variation. Admixture model could incorporate and use ancestral genomic information.

Associations between genetic variants in the TGF-β signaling pathway and breast cancer risk among Hispanic and non-Hispanic white women

The TGF-β signaling pathway has a significant role in breast cancer initiation and promotion by regulating various cellular processes. We evaluated whether genetic variation in eight genes (TGF-β1, TGF-β2, TGF-βR1, TGF-βR2, TGF-βR3, RUNX1, RUNX2, and RUNX3) is associated with breast cancer risk in women from the Breast Cancer Health Disparities Study. A total of 3,524 cases (1,431 non-Hispanic whites (NHW); 2,093 Hispanics/Native Americans(NA)) and 4,209 population-based controls (1,599 NHWs; 2,610 Hispanics/NAs) were included in analyses. Genotypes for 47 single nucleotide polymorphisms (SNPs) were determined. Additionally, 104 ancestral informative markers estimated proportion of NA ancestry. Associations with breast cancer risk overall, by menopausal status, NA ancestry, and estrogen receptor (ER)/progesterone receptor tumor phenotype were evaluated. After adjustment for multiple comparisons, two SNPs were significantly associated with breast cancer risk: RUNX3 (rs906296 ORCG/GG = 1.15 95 % CI 1.04-1.26) and TGF-β1 (rs4803455 ORCA/AA = 0.89 95 % CI 0.81-0.98). RUNX3 (rs906296) and TGF-βR2 (rs3773644) were associated with risk in pre-menopausal women (p adj = 0.002 and 0.02, respectively) and in those with intermediate to high NA ancestry (p adj = 0.04 and 0.01, respectively). Self-reported race was strongly correlated with NA ancestry (r = 0.86). There was a significant interaction between NA ancestry and RUNX1 (rs7279383, p adj = 0.04). Four RUNX SNPs were associated with increased risk of ER- tumors. Results provide evidence that genetic variation in TGF-β and RUNX genes are associated with breast cancer risk. This is the first report of significant associations between genetic variants in TGF-β and RUNX genes and breast cancer risk among women of NA ancestry.

On the Role of Genetic Testing for Personalized Drug Overdose Management

Author Reply: We thank our colleagues for their interest in our study entitled “Opioid Receptor Polymorphism A118G Associated with Clinical Severity in a Drug Overdose Population.” Our results add to the growing literature over the past decade that implicate a handful of promising single nucleotide polymorphisms (SNPs) of the mu opioid receptor gene (OPRM1) as candidates for clinically relevant variability in baseline mesolimbic reward neurobiology (dopamine–opioid interaction), opioid sensitivity, and addiction [1]. Our findings warrant further research to understand the mechanisms underlying specific at-risk overdose populations. We completely concur that results of our pilot study, as with all such investigations, will require validation in larger populations, an effort which is currently being addressed at our institution. Confirming our results would have significant impact in the field of addiction to pave the way for personalized prescription practices not only for opioids, but for those at risk for drug overdose. Our data which demonstrated higher overdose severity in G allele subjects, not limited to opioid drugs, is likely due to dopamine–opioid interactions in the mesolimbic/striatal pathways relevant to reward and habit formation. Indeed, several lines of evidence have established significant disturbances of the opioid system in association with various drugs of abuse [2, 3]. We therefore chose not to limit the analysis to only opioids given the biologic plausibility of enhanced abuse and addiction behaviors which apply for all drugs, not limited to opioids. To address our colleagues’ suggestion to eliminate sympathomimetics, such as cocaine, from the analysis, we would argue that it is equally plausible that OPRM1 variants affect the same reward pathways for sympathomimetics, and thus arbitrary removal of these exposures would actually introduce, not eliminate, bias. A question was also raised as to whether the 118G allele confers resistance rather than increased susceptibility as suggested by the findings of our study. Consistent with the results of our study, multiple investigations have reported an association of the 118G allele with opioid abuse [4–6]. However, the mu opioid receptor is involved in multiple physiological functions, thus the 118G allele could be beneficial for some processes, but adverse for others. Our colleagues also question whether race/ethnicity may have introduced confounding into our analysis. To truly control for the effect of racial bias, it would be necessary to not only gather self-reported data, which is difficult to gather on critically ill patients with altered mental status due to overdose, but also it would be necessary to perform additional analyses such as ancestral informative markers (AIMs), which we did not have available at the time. The poor specificity of racial/ethnic variables in addiction research is often compounded by failure to measure social and environmental exposures that track with self-identified race in the USA, thereby masking important gene–environment effects. Missing these effects means missing an opportunity to disentangle the complex social, environmental, behavioral, and genetic factors that interact to create disease and determine treatment outcomes [7]. To account for this, future studies of OPRM1 variants in overdose populations should gather social and environmental variables as well as perform AIMs analysis.

Matrix Metalloproteinase Genes Are Associated with Breast Cancer Risk and Survival: The Breast Cancer Health Disparities Study

Matrix metalloproteinases (MMPs) contribute to cancer through their involvement in cancer invasion and metastasis. We evaluated genetic variation in MMP1 (9 SNPs), MMP2 (8 SNPs), MMP3 (4 SNPs), and MMP9 (3 SNPs) and breast cancer risk among Hispanic (2111 cases, 2597 controls) and non-Hispanic white (NHW) (1481 cases, 1586 controls) women in the Breast Cancer Health Disparities Study. Ancestral informative markers (n = 104) were assessed to determine Native American (NA) ancestry. MMP1 [4 single nucleotide polymorphisms (SNPs)] and MMP2 (2 SNPs) were associated with breast cancer overall. MMP1 rs996999 had strongest associations among women with the most NA ancestry (OR 1.61,95% CI 1.09,2.40) as did MMP3 rs650108 (OR 1.36, 95% CI 1.05,1.75) and MMP9 rs3787268 (OR 1.52, 95% CI 1.09,2.13). The adaptive rank truncated product (ARTP) showed a significant pathway partp value of 0.04, with a stronger association among women with the most NA ancestry (partp = 0.02). Significant pathway genes using the ARTP were MMP1 for all women (partp = 0.02) and MMP9 for women with the most NA ancestry (partp = 0.024); MMP2 was borderline significant overall (partp = 0.06) and MMP1 and MMP3 were borderline significant for women with the most NA ancestry (partp = 0.07 and 0.06 respectively). MMP1 and MMP2 were associated with ER+/PR+ and ER+/PR-tumors; MMP3 and MMP9 were associated with ER−/PR− tumors. The pathway was highly significant with survival (partp = 0.0041) with MMP2 having the strongest gene association (partp = 0.0007). Our findings suggest that genetic variation in MMP genes influence breast cancer development and survival in this genetically admixed population.

Associations of PON1 and Genetic Ancestry with Obesity in Early Childhood

Obesity in children has become an epidemic in the U.S. and is particularly prominent in minority populations such as Mexican-Americans. In addition to physical activity and diet, genetics also plays a role in obesity etiology. A few studies in adults and adolescents suggest a link between obesity and paraoxonase 1 (PON1), a multifunctional enzyme that can metabolize organophosphate pesticides and also has antioxidant properties. We determined PON1192 genotype and arylesterase levels (ARYase, measure of PON1 enzyme quantity), to characterize the relationship between PON1 and obesity in young Mexican-American children (n = 373) living in an agricultural community in California. Since PON1 polymorphisms and obesity both vary between ethnic groups, we estimated proportional genetic ancestry using 106 ancestral informative markers (AIMs). Among children, PON1192 allele frequencies were 0.5 for both alleles, and the prevalence of obesity was high (15% and 33% at ages two and five, respectively). The average proportion of European, African, and Native American ancestry was 0.40, 0.09, and 0.51, yet there was wide inter-individual variation. We found a significantly higher odds of obesity (9.3 and 2.5- fold) in PON1192QQ children compared to PON1192RR children at ages two and five, respectively. Similar relationships were seen with BMI Z-scores at age two and waist circumference at age five. After adjusting for genetic ancestry in models of PON1 and BMI Z-score, effect estimates for PON1192 genotype changed 15% and 9% among two and five year old children, respectively, providing evidence of genetic confounding by population stratification. However even after adjustment for genetic ancestry, the trend of increased BMI Z-scores with increased number of PON1192 Q alleles remained. Our findings suggest that PON1 may play a role in obesity independent of genetic ancestry and that studies of PON1 and health outcomes, especially in admixed populations, should account for differences due to population stratification.

Genetic variation in bone morphogenetic proteins and breast cancer risk in hispanic and non‐hispanic white women: The breast cancer health disparities study

Bone morphogenetic proteins (BMP) are thought to be important in breast cancer promotion and progression. We evaluated genetic variation in BMP-related genes and breast cancer risk among Hispanic (2,111 cases, 2,597 controls) and non-Hispanic White (NHW) (1,481 cases, 1,586 controls) women who participated in the 4-Corner's Breast Cancer Study, the Mexico Breast Cancer Study and the San Francisco Bay Area Breast Cancer Study. BMP genes and their receptors evaluated include ACVR1, AVCR2A, ACVR2B, ACVRL1, BMP1, BMP2, BMP4, BMP6, BMP7, BMPR1A, BMPR1B, BMPR2, MSTN and GDF10. Additionally, 104 ancestral informative markers were assessed to discriminate between European and native American ancestry. The importance of estrogen on BMP-related associations was suggested through unique associations by menopausal status and estrogen (ER) and progesterone (PR) receptor status of tumors. After adjustment for multiple comparisons ACVR1 (8 SNPs) was modestly associated with ER+PR+ tumors [odds ratios (ORs) between 1.18 and 1.39 padj < 0.05]. ACVR1 (3 SNPs) and BMP4 (3 SNPs) were associated with ER+PR- tumors (ORs 0.59-2.07; padj < 0.05). BMPR2 was associated with ER-PR+ tumors (OR 4.20; 95% CI 1.62, 10.91; padj < 0.05) as was GDF10 (2 SNPs; ORs 3.62 and 3.85; padj < 0.05). After adjustment for multiple comparisons several SNPs remained associated with ER-PR- tumors (padj < 0.05) including ACVR1 BMP4 and GDF10 (ORs between 0.53 and 2.12). Differences in association also were observed by percentage of native ancestry and menopausal status. Results support the hypothesis that genetic variation in BMPs is associated with breast cancer in this admixed population.

Atherosclerosis and Vascular Biology

Atherosclerosis and Vascular Biology

Abstract A65: Association between genetic ancestry and breast cancer tumor characteristics among admixed Latina and Native Hawaiian populations: The Multiethnic Cohort.

Abstract Introduction: Breast cancer incidence and mortality rates vary dramatically across racial/ethnic groups. For instance, the incidence rate of breast cancer among Native Hawaiians is higher than that of European Americans with lower incidence of disease seen among Latinas. However, both Latinas and Native Hawaiians are more likely to be diagnosed with later stage breast cancer, and whether genetic ancestry contributes to tumor characteristics remains unclear. Therefore, we investigated the association between genetic ancestry and breast cancer tumor characteristics among two admixed populations, Latinas and Native Hawaiians, within the Multiethnic Cohort study (MEC). Methods: We used the Taqman Open Array platform to genotype 93 ancestral informative markers (AIMs), which could assess major continental ancestry, in 22,932 self-reported African American, European American, Japanese American, Latino, and Native Hawaiian MEC participants as part of an on-going study. The STRUCTURE software was used in the available ancestral populations (HapMap CEU, JPT and YRI and American Indians from HGDP) to determine and enhance the accuracy of the percent ancestry estimation for each individual. For this study, 651 Latina and Native Hawaiian breast cancer cases from our nested case-control study were examined. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) to evaluate the associations of genetic ancestry with breast cancer stage, cell differentiation, and hormone receptor information. The models were adjusted for age at cancer diagnosis, mammographic screening, family history of breast cancer, education, age at menarche, age at first child birth, number of children, menopausal status, oral contraceptive use, hormone replacement therapy use and body mass index. Results: Among Native Hawaiian (n=193) breast cancer cases, a 10% increase in Native Hawaiian ancestry was positively associated with advanced stage of disease (regional/metastastic) in comparison to localized disease (OR=1.18; 95% CI: 1.02-1.37). Among Latina breast cancer cases (n=410), a 10% increase in American Indian ancestry was inversely associated with advanced stage of disease (OR=0.91; 95% CI: 0.85-0.99); however, a suggestive positive association was found with poorer breast cancer cell differentiation (OR=1.08; 95% CI: 0.99-1.16). Among those with hormone receptor information, we did not detect an association between genetic ancestry and estrogen receptor negative (ER-) or progesterone receptor negative (PR-) status in Latinas. However, for Native Hawaiians, Hawaiian ancestry had a suggestive positive association with PR- status breast cancer (n=123; OR=1.22; 95% CI: 0.99-1.50), and East Asian Ancestry had a suggestive positive association with ER-/PR- status (n=109; OR=1.49; 95% CI: 0.98-2.26). Conclusion: Our findings suggest that genetic ancestry may contribute to breast cancer tumor characteristics among admixed populations. Citation Format: Sungshim L. Park, Hansong Wang, Christian P. Caberto, Maarit Tiirikainen, Lynne R. Wilkens, Laurence N. Kolonel, Brian E. Henderson, Christopher A. Haiman, Loic Le Marchand, Iona Cheng. Association between genetic ancestry and breast cancer tumor characteristics among admixed Latina and Native Hawaiian populations: The Multiethnic Cohort. [abstract]. In: Proceedings of the Fifth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2012 Oct 27-30; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(10 Suppl):Abstract nr A65.