Back to Authors

Sinnwell, Jason P

0000-0003-1964-5522

Mayo Clinic

Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN 55905, USA.

Citations 21

Whole-Exome Sequencing-Based Linkage Analysis of Multiple Myeloma (MM) and Monoclonal Gammopathy of Undetermined Significance (MGUS) Pedigrees
Camp, Nicola J. , Wei, Xiaomu , Earle, Angel, Norman, Aaron D. , Sinnwell, Jason P. , Demangel, Delphine , Griffin, R. L. , McKay, James , Offit, Kenneth , Vijai, Joseph , Chen, Siwei , O’Brien, Daniel , Klein, Robert J. , Kumar, Shaji, Lipkin, Steven M. , Vachon, Celine M. , Waller, Rosalie G. , Clay-Gilmour, Alyssa I, Camp, Nicola J , Norman, Aaron D , Sinnwell, Jason P , Griffin, Rosalie , Offit, Kenneth , Joseph, Vijai , Rajkumar, Vincent, Klein, Robert , Lipkin, Steve , Waller, Rosalie G , Clay‐Gilmour, Alyssa , Dumontet, Charles , Rajkumar, S. Vincent , Kumar, Shaji , Vachon, Celine M.

Cancers | November 10, 2025 | Volume: 17 | Issue: 22 | Pages: 3611

10.3390/cancers17223611 Get It

Background/Objectives: Family history is a known risk factor for multiple myeloma (MM) and its precursor condition, monoclonal gammopathy of undetermined significance (MGUS). Previous genome-wide association studies (GWASs) have identified 35 common loci associated with MM risk and 21 associated with MGUS. The objective of this study was to identify less common and rare genetic loci predisposing to MM/MGUS through whole-exome sequencing (WES)-based linkage analysis. Methods:Multipoint linkage analysis was conducted using the Multipoint Engine for Rapid Likelihood Inference (MERLIN) with the Lander–Green algorithm on germline WES data from 79 pedigrees with 2 or more affected relatives (120 MM, 86 MGUS, and 21 unaffected). Genome-wide linkage was evaluated using 12,946 independent single-nucleotide variants (linkage disequilibrium r2 < 0.05). Results: Significant linkage was observed at chromosome 6q22.33–q24.2 by the non-parametric model (logarithm-of-odds (LOD) = 3.3) and suggestive linkage by the dominant parametric model (heterogeneity LOD (HLOD) = 2.5). Fourteen rare variants within this region were prioritized using family-specific partial LOD scores and in silico functional prediction tools. Nine of these variants, REPS1, THEMIS, TAAR6, AHI1, VNN1, VNN3, MTFR2/FAM54A, LAMA2, and PHACTR2, overlapped immune-regulatory regions in blood cell lines and were not previously identified in GWASs. Conclusions: This study demonstrates the utility of applying a linkage analysis framework to familial WES data for identifying genomic regions and candidate genes that may contribute to MM/MGUS predisposition. These findings provide new insight into the inherited risk and etiology of familial MM and MGUS.
Pedixplorer : a Bioconductor package to streamline pedigree design and visualization
Nézet, Louis Le, Letko, Anna , André, Catherine , Quignon, Pascale , Le Nézet, Louis , Sinnwell, Jason P , Letko, Anna , Sinnwell, Jason P.

Bioinformatics | June 3, 2025 | Volume: 41 | Issue: 6 | Pages: No page available

10.1093/bioinformatics/btaf329 Get It

Abstract Motivation Understanding kinship relationships is fundamental to genetic research, particularly in the context of genetic linkage studies and population genetics. Pedigree design and analysis are a prerequisite for these investigations. The legacy kinship2 CRAN package has been a cornerstone in this area; however, the need for handling larger and more complex datasets necessitates an updated, flexible, and user-friendly toolset. To address this issue, we present Pedixplorer, a novel Bioconductor package designed to enhance kinship analyses with modern functionality and usability, especially in large multigeneration complex pedigrees with inbreeding loops, which are frequently seen in domestic animal breeding. Results Pedixplorer builds upon the robust foundation of kinship2, integrating Bioconductor standards and most recent programming practices. Its core component is the S4 Pedigree object, facilitating efficient representation of complex pedigrees. The new functions enable automatic querying, filtering, and trimming of large pedigrees, while the graphical functions have been rewritten for better customization in pedigree visualizations. Additionally, Pedixplorer offers a comprehensive Shiny application, accessible both locally and via a dedicated website, allowing non-R users to easily create, filter, and customize pedigrees. Availability and implementation The Pedixplorer package is freely available at: https://www.bioconductor.org/packages/release/bioc/html/Pedixplorer.html with additional documentation at https://louislenezet.github.io/Pedixplorer. A user-friendly web application is available at: https://pedixplorer.univ-rennes.fr.
Breast Cancer Polygenic-Risk Score Influence on Risk-Reducing Endocrine Therapy Use: Genetic Risk Estimate (GENRE) Trial 1-Year and 2-Year Follow-Up
Stan, Daniela , Kim, Julian O. , Schaid, Daniel J. , Carlson, Erin E. , Kim, Christina , Couch, Fergus J. , Vachon, Celine M. , Cooke, Andrew , Goldenberg, Benjamin A. , Pruthi, Sandhya , Couch, Fergus J. , Stan, Daniela L , Kim, Christina A , Sinnwell, Jason P , Vachon, Celine M. , Cooke, Andrew L , Goldenberg, Benjamin , Pruthi, Sandhya , Sinnwell, Jason P.

Cancer Prevention Research | December 28, 2023 | Volume: 17 | Issue: 2 | Pages: 77-84

10.1158/1940-6207.capr-23-0256 Get It

Abstract Refinement of breast cancer risk estimates with a polygenic-risk score (PRS) may improve uptake of risk-reducing endocrine therapy (ET). A previous clinical trial assessed the influence of adding a PRS to traditional risk estimates on ET use. We stratified participants according to PRS-refined breast cancer risk and evaluated ET use and ET-related quality of life (QOL) at 1-year (previously reported) and 2-year follow-ups. Of 151 participants, 58 (38.4%) initiated ET, and 22 (14.6%) discontinued ET by 2 years; 42 (27.8%) and 36 (23.8%) participants were using ET at 1- and 2-year follow-ups, respectively. At the 2-year follow-up, 39% of participants with a lifetime breast cancer risk of 40.1% to 100.0%, 18% with a 20.1% to 40.0% risk, and 16% with a 0.0% to 20.0% risk were taking ET (overall P = 0.01). Moreover, 40% of participants whose breast cancer risk increased by 10% or greater with addition of the PRS to a traditional breast cancer-risk model were taking ET versus 0% whose risk decreased by 10% or greater (P = 0.004). QOL was similar for participants taking or not taking ET at 1- and 2-year follow-ups, although most who discontinued ET did so because of adverse effects. However, these QOL results may have been skewed by the long interval between QOL surveys and lack of baseline QOL data. PRS-informed breast cancer prevention counseling has a lasting, but waning, effect over time. Additional follow-up studies are needed to address the effect of PRS on ET adherence, ET-related QOL, supplemental breast cancer screening, and other risk-reducing behaviors. Prevention Relevance: Risk-reducing medications for breast cancer are considerably underused. Informing women at risk with precise and individualized risk assessment tools may substantially affect the incidence of breast cancer. In our study, a risk assessment tool (IBIS-polygenic-risk score) yielded promising results, with 39% of women at highest risk starting preventive medication.
Molecular Profile Changes in Patients with Castrate-Resistant Prostate Cancer Pre- and Post-Abiraterone/Prednisone Treatment
Sicotte, Hugues , Qin, Sisi , Dehm, Scott M. , Bhargava, Vipul , Gormley, Michael , Tan, Winston , Hillman, David W. , Li, Ying , Vedell, Peter T. , Carlson, Rachel E. , Bryce, Alan H. , Jimenez, Raphael E., Weinshilboum, Richard M. , Wang, Liewei , Kalari, Krishna R , Qin, Sisi , Dehm, Scott M , Bhargava, Vipul , Gormley, Michael , Tan, Winston , Sinnwell, Jason P , Hillman, David W , Li, Ying , Vedell, Peter T , Carlson, Rachel E , Bryce, Alan H , Jimenez, Raphael E , Weinshilboum, Richard M. , Kohli, Manish , Wang, Liewei , Kalari, Krishna R. , Sinnwell, Jason P. , Kohli, Manish

Molecular Cancer Research | September 22, 2022 | Volume: 20 | Issue: 12 | Pages: 1739-1750

10.1158/1541-7786.mcr-22-0099 Get It

Abstract We identified resistance mechanisms to abiraterone acetate/prednisone (AA/P) in patients with metastatic castration-resistant prostate cancer (mCRPC) in the Prostate Cancer Medically Optimized Genome-Enhanced Therapy (PROMOTE) study. We analyzed whole-exome sequencing (WES) and RNA-sequencing data from 83 patients with metastatic biopsies before (V1) and after 12 weeks of AA/P treatment (V2). Resistance was determined by time to treatment change (TTTC). At V2, 18 and 11 of 58 patients had either short-term (median 3.6 months; range 1.4–4.5) or long-term (median 29 months; range 23.5–41.7) responses, respectively. Nonresponders had low expression of TGFBR3 and increased activation of the Wnt pathway, cell cycle, upregulation of AR variants, both pre- and posttreatment, with further deletion of AR inhibitor CDK11B posttreatment. Deletion of androgen processing genes, HSD17B11, CYP19A1 were observed in nonresponders posttreatment. Genes involved in cell cycle, DNA repair, Wnt-signaling, and Aurora kinase pathways were differentially expressed between the responder and non-responder at V2. Activation of Wnt signaling in nonresponder and deactivation of MYC or its target genes in responders was detected via SCN loss, somatic mutations, and transcriptomics. Upregulation of genes in the AURKA pathway are consistent with the activation of MYC regulated genes in nonresponders. Several genes in the AKT1 axis had increased mutation rate in nonresponders. We also found evidence of resistance via PDCD1 overexpression in responders. Implications: Finally, we identified candidates drugs to reverse AA/P resistance: topoisomerase inhibitors and drugs targeting the cell cycle via the MYC/AURKA/AURKB/TOP2A and/or PI3K_AKT_MTOR pathways.
Does a Multiple Myeloma Polygenic Risk Score Predict Overall Survival of Patients with Myeloma?
Macauda, Angelica , Clay‐Gilmour, Alyssa , Hielscher, Thomas , Kruszewski, Marcin , Orlowski, Robert Z. , Kumar, Shaji , Ziv, Elad , Brown, Elizabeth E. , Waller, Rosalie G. , Machiela, Mitchell J. , Camp, Nicola J. , Raźny, Małgorzata , Várkonyi, Judit , Piredda, Chiara , Pelosini, Matteo , Belachew, Alem A. , Rybicka‐Ramos, Malwina, Goldschmidt, Hartmut , Tomczak, Waldemar , Sáinz, Juan , Butrym, Aleksandra , Wątek, Marzena , Iskierka‐Jazdzewska, Elżbieta , Buda, Gabriele , Robinson, Dennis P. , Dudziński, Marek , Martínez‐López, Joaquín , Reis, Rui Manuel , Weinhold, Niels , Bhatti, Parveen , Carvajal‐Carmona, Luis G. , Zawirska, Daria , Mazur, Grzegorz , Berndt, Sonja I. , Campa, Daniele , Vachon, Celine M. , Martinez-Lopez, Joaquin , Griffin, R. L. , Kruszewski, Marcin , Orlowski, Robert Z. , Kumar, Shaji K , Ziv, Elad , Försti, Asta , Waller, Rosalie G , Machiela, Mitchell J , Chanock, Stephen Jacob , Camp, Nicola J , Rymko, Marcin , Raźny, Małgorzata , Cozen, Wendy , Piredda, Chiara , Pelosini, Matteo , Belachew, Alem A , Subocz, Edyta , Giles, Graham G , Milne, Roger L , Zaucha, Jan Maciej , Vangsted, Annette Juul , Goldschmidt, Hartmut , Rajkumar, S Vincent , Tomczak, Waldemar , Sainz, Juan , Watek, Marzena , Iskierka-Jazdzewska, Elżbieta , Buda, Gabriele , Dudziński, Marek , Martinez-Lopez, Joaquin , Sinnwell, Jason P , Slager, Susan L , Reis, Rui Manuel , Weinhold, Niels , Bhatti, Parveen , Carvajal-Carmona, Luis G , Zawirska, Daria , Mazur, Grzegorz , Berndt, Sonja I , Vachon, Celine M. , Canzian, Federico , Martinez-Lopez, Joaquin , Butrym, Aleksandra , Griffin, Rosalie , Hildebrandt, Michelle A.T. , Orciuolo, Enrico , Försti, Asta , Rymko, Marcin , Cozen, Wendy , Subocz, Edyta , Hemminki, Kari , Giles, Graham G. , Milne, Roger L. , Hofmann, Jonathan N. , Zaucha, Jan Maciej , Rajkumar, S. Vincent , Jurczyszyn, Artur , Sinnwell, Jason P. , Slager, Susan L. , Jamroziak, Krzysztof , Norman, Aaron D. , Canzian, Federico

Cancer Epidemiology, Biomarkers & Prevention | June 14, 2022 | Volume: 31 | Issue: 9 | Pages: 1863-1866

10.1158/1055-9965.epi-22-0043 Get It

Abstract Background: Genome-wide association studies (GWAS) of multiple myeloma in populations of European ancestry (EA) identified and confirmed 24 susceptibility loci. For other cancers (e.g., colorectum and melanoma), risk loci have also been associated with patient survival. Methods: We explored the possible association of all the known risk variants and their polygenic risk score (PRS) with multiple myeloma overall survival (OS) in multiple populations of EA [the International Multiple Myeloma rESEarch (IMMEnSE) consortium, the International Lymphoma Epidemiology consortium, CoMMpass, and the German GWAS] for a total of 3,748 multiple myeloma cases. Cox proportional hazards regression was used to assess the association between each risk SNP with OS under the allelic and codominant models of inheritance. All analyses were adjusted for age, sex, country of origin (for IMMEnSE) or principal components (for the others) and disease stage (ISS). SNP associations were meta-analyzed. Results: SNP associations were meta-analyzed. From the meta-analysis, two multiple myeloma risk SNPs were associated with OS (P &lt; 0.05), specifically POT1-AS1-rs2170352 [HR = 1.37; 95% confidence interval (CI) = 1.09–1.73; P = 0.007] and TNFRSF13B-rs4273077 (HR = 1.19; 95% CI = 1.01–1.41; P = 0.04). The association between the combined 24 SNP MM-PRS and OS, however, was not significant. Conclusions: Overall, our results did not support an association between the majority of multiple myeloma risk SNPs and OS. Impact: This is the first study to investigate the association between multiple myeloma PRS and OS in multiple myeloma.
Prevalence of heavy chain MGUS by race and family history risk groups using a high-sensitivity screening method
Vachon, Celine M. , Murray, Josiah , Allmer, Cristine, Larson, Dirk R. , Kleinstern, Geffen , Kyle, Robert A. , Kumar, Shaji , Murray, David , Larson, Dirk , Sinnwell, Jason P , Dispenzieri, Angela , Slager, Susan L , Kumar, Shaji K , Murray, David L., Murray, Josiah D , Vachon, Celine M. , Norman, Aaron D. , Sinnwell, Jason P. , Dispenzieri, Angela , Visram, Alissa , Rajkumar, S. Vincent , Slager, Susan L.

Blood Advances | March 22, 2022 | Volume: 6 | Issue: 12 | Pages: 3746-3750

10.1182/bloodadvances.2021006201 Get It

Abstract Mass-spectrometry (MS) assays detect lower levels of monoclonal proteins and result in earlier detection of monoclonal gammopathy of undetermined significance (MGUS). We examined heavy chain MGUS prevalence using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS among 3 risk groups, ages 50 or older: 327 African Americans (AA) and 1223 European Americans (EA) from a clinical biobank and 1093 unaffected first-degree relatives (FDR) of patients with hematologic disorders. Age- and sex-adjusted prevalence rates were directly standardized to 2010 United States population. Prevalence ratios were estimated for comparisons of AA and FDR to the EA group using the Poisson distribution. Results were also compared with population-based prevalence using conventional gel-based methods. Risk groups had similar sex and age distributions. MALDI-TOF MGUS prevalence was higher in the AA (16.5% [95% confidence interval (CI), 12.2%, 20.8%]) and FDR (18.3% [95% CI, 16.6%, 21.6%]) than in EA (10.8% [95% CI, 8.8%, 12.7%]), translating to prevalence ratios of 1.73 (95% CI, 1.31, 2.29) and 1.90 (95% CI, 1.55, 2.34), respectively. MALDI-TOF EA prevalence was over threefold higher than conventional estimates but showed similar age trends. Thus, the MALDI-TOF assay found greater numbers with MGUS but similar relative differences by race, family history, and age as prior studies.
Penalized mediation models for multivariate data
Schaid, Daniel J. , Dikilitas, Ozan , Kullo, Iftikhar J. , Sinnwell, Jason P , Kullo, Iftikhar J , Dikilitas, Ozan , Sinnwell, Jason P.

Genetic Epidemiology | October 21, 2021 | Volume: 46 | Issue: 1 | Pages: 32-50

10.1002/gepi.22433 Get It

AbstractStatistical methods to integrate multiple layers of data, from exposures to intermediate traits to outcome variables, are needed to guide interpretation of complex data sets for which variables are likely contributing in a causal pathway from exposure to outcome. Statistical mediation analysis based on structural equation models provide a general modeling framework, yet they can be difficult to apply to high‐dimensional data and they are not automated to select the best fitting model. To overcome these limitations, we developed novel algorithms and software to simultaneously evaluate multiple exposure variables, multiple intermediate traits, and multiple outcome variables. Our penalized mediation models are computationally efficient and simulations demonstrate that they produce reliable results for large data sets. Application of our methods to a study of vascular disease demonstrates their utility to identify novel direct effects of single‐nucleotide polymorphisms (SNPs) on coronary heart disease and peripheral artery disease, while disentangling the effects of SNPs on the intermediate risk factors including lipids, cigarette smoking, systolic blood pressure, and type 2 diabetes.
Characteristics and Spatially Defined Immune (micro)landscapes of Early-stage PD-L1–positive Triple-negative Breast Cancer
Carter, Jodi M. , Polley, Mei‐Yin C. , Leon‐Ferre, Roberto A. , Thompson, Kevin J. , Wang, Xue , Ma, Yaohua , Zahrieh, David , Kachergus, Jennifer M., Solanki, Malvika , Liu, Minetta C. , Thompson, E. Aubrey , Sinnwell, Jason P , Thompson, Kevin J , Boughey, JC , Liu, Minetta , Ingle, J , Goetz, Matthew P , Carter, Jodi , Sinnwell, Jason P. , Boughey, Judy C. , Ingle, James N. , Kalari, Krishna R. , Couch, Fergus J. , Goetz, Matthew P.

Clinical Cancer Research | June 9, 2021 | Volume: 27 | Issue: 20 | Pages: 5628-5637

10.1158/1078-0432.ccr-21-0343 Get It

Abstract Purpose: Programmed death ligand 1 [PD-(L)1]-targeted therapies have shown modest survival benefit in triple-negative breast cancer (TNBC). PD-L1+ microenvironments in TNBC are not well characterized and may inform combinatorial immune therapies. Herein, we characterized clinicopathologic features, RNA-based immune signatures, and spatially defined protein-based tumor–immune microenvironments (TIME) in early-stage PD-L1+ and PD-L1− TNBC. Experimental Design: From a large cohort of chemotherapy-naïve TNBC, clinicopathologic features, deconvoluted RNA immune signatures, and intraepithelial and stromal TIME (Nanostring GeoMX) were identified in subsets of PD-L1+ and PD-L1− TNBC, as defined by FDA-approved PD-L1 companion assays. Results: 228 of 499 (46%) TNBC were PD-L1+ (SP142: ≥1% immune cells-positive). Using PD-L1 22C3, 46% had combined positive score (CPS) ≥ 1 and 16% had CPS ≥10. PD-L1+ TNBC were higher grade with higher tumor-infiltrating lymphocytes (TIL; P &lt; 0.05). PD-L1 was not associated with improved survival following adjustment for TILs and other variables. RNA profiles of PD-L1+ TNBC had increased dendritic cell, macrophage, and T/B cell subset features; and decreased myeloid-derived suppressor cells. PD-L1+ stromal and intraepithelial TIMEs were highly enriched in IDO-1, HLA-DR, CD40, and CD163 compared with PD-L1-TIME, with spatially specific alterations in CTLA-4, Stimulator of Interferon Genes (STING), and fibronectin. Macrophage- and antigen presentation–related proteins correlated most strongly with PD-L1 protein. Conclusions: In this early-stage TNBC cohort, nearly 50% were PD-L1+ (SP142 companion assay) while 16% were PD-L1+ with the 22C3 companion assay. PD-L1+ TNBC had specific myeloid-derived and lymphoid features. Spatially defined PD-L1+ TIME were enriched in several clinically actionable immune proteins. These data may inform future studies on combinatorial immunotherapies for patients with PD-L1+ TNBC. See related commentary by Symmans, p. 5446
Patient-Derived Xenograft Engraftment and Breast Cancer Outcomes in a Prospective Neoadjuvant Study (BEAUTY)
Boughey, Judy C. , Yu, Jia , Santo, Katelyn, Carter, Jodi M. , McLaughlin, Sarah A. , Moreno‐Aspitia, Alvaro , Northfelt, Donald W. , Gray, Richard J. , Hunt, Katie N. , Conners, Amy Lynn , Moyer, Ann M. , Weinshilboum, Richard, Copland, John A. , Wang, Liewei , Sinnwell, Jason P , Gray, Richard J , Ingle, J , Moyer, AM , Goetz, Matthew P , Boughey, JC , Carter, Jodi , Suman, Vera J. , Sinnwell, Jason P. , Kalari, Krishna R. , Tang, Xiaojia , Ingle, James N. , Goetz, Matthew P.

Clinical Cancer Research | June 2, 2021 | Volume: 27 | Issue: 17 | Pages: 4696-4699

10.1158/1078-0432.ccr-21-0641 Get It

Abstract Purpose: Patient-derived xenografts (PDX) are a research tool for studying cancer biology and drug response phenotypes. While engraftment rates are higher for tumors with more aggressive characteristics, it is uncertain whether engraftment is prognostic for cancer recurrence. Patients and Methods: In a prospective study of patients with breast cancer treated with neoadjuvant chemotherapy (NAC) with taxane ± trastuzumab followed by anthracycline-based chemotherapy, we report the association between breast cancer events and PDX engraftment using tumors derived from treatment naïve (pre-NAC biopsies from 113 patients) and treatment resistant (post-NAC at surgery from 34 patients). Gray test was used to assess whether the cumulative incidence of a breast cancer event differs with respect to either pre-NAC PDX engraftment or post-NAC PDX engraftment. Results: With a median follow-up of 5.7 years, the cumulative incidence of breast cancer relapse did not differ significantly according to pre-NAC PDX engraftment (5-year rate: 13.6% vs. 13.4%; P = 0.89). However, the incidence of a breast event was greater for patients with post-NAC PDX engraftment (5-year rate: 50.0% vs. 19.6%), but this did not achieve significance (P = 0.11). Conclusions: In treatment-naïve breast cancer receiving standard NAC, PDX engraftment was not prognostic for breast cancer recurrence. Further study is needed to establish whether PDX engraftment in the treatment-resistant setting is prognostic for cancer recurrence.
Impact of Personalized Genetic Breast Cancer Risk Estimation With Polygenic Risk Scores on Preventive Endocrine Therapy Intention and Uptake
Schaid, Daniel J. , Vachon, Celine M. , Cooke, Andrew , Kim, Christina , Sinnwell, Jason P. , Hasadsri, Linda , Stan, Daniela , Goldenberg, Benjamin A. , Neal, Lonzetta, Grenier, Debjani, Thicke, Lori A., Pruthi, Sandhya , Vachon, Celine M. , Sinnwell, Jason P , Stan, Daniela L , Goldenberg, Benjamin , Degnim, Amy C , Kim, Christina A , Kim, Julian O. , Couch, Fergus J. , Degnim, Amy C.

Cancer Prevention Research | October 23, 2020 | Volume: 14 | Issue: 2 | Pages: 175-184

10.1158/1940-6207.capr-20-0154 Get It

Abstract Endocrine therapy is underutilized to reduce breast cancer incidence among women at increased risk. Polygenic risk scores (PRSs) assessing 77 breast cancer genetic susceptibility loci personalizes risk estimates. We examined effect of personalized PRS breast cancer risk prediction on intention to take and endocrine therapy uptake among women at increased risk. Eligible participants had a 10-year breast cancer risk ≥5% by Tyrer–Cuzick model [International Breast Cancer Intervention Study (IBIS)] or ≥3.0 % 5-year Gail Model risk with no breast cancer history or hereditary breast cancer syndrome. Breast cancer risk was estimated, endocrine therapy options were discussed, and endocrine therapy intent was assessed at baseline. After genotyping, PRS-updated breast cancer risk estimates, endocrine therapy options, and intent to take endocrine therapy were reassessed; endocrine therapy uptake was assessed during follow-up. From March 2016 to October 2017, 151 patients were enrolled [median (range) age, 56.1 (36.0–76.4 years)]. Median 10-year and lifetime IBIS risks were 7.9% and 25.3%. Inclusion of PRS increased lifetime IBIS breast cancer risk estimates for 81 patients (53.6%) and reduced risk for 70 (46.4%). Of participants with increased breast cancer risk by PRS, 39 (41.9%) had greater intent to take endocrine therapy; of those with decreased breast cancer risk by PRS, 28 (46.7%) had less intent to take endocrine therapy (P &lt; 0.001). On multivariable regression, increased breast cancer risk by PRS was associated with greater intent to take endocrine therapy (P &lt; 0.001). Endocrine therapy uptake was greater among participants with increased breast cancer risk by PRS (53.4%) than with decreased risk (20.9%; P &lt; 0.001). PRS testing influenced intent to take and endocrine therapy uptake. Assessing PRS effect on endocrine therapy adherence is needed. Prevention Relevance: Counseling women at increased breast cancer risk using polygenic risk score (PRS) risk estimates can significantly impact preventive endocrine therapy uptake. Further development of PRS testing to personalize breast cancer risk assessments and endocrine therapy counselling may serve to potentially reduce the incidence of breast cancer in the future.