An original phylogenetic approach identified mitochondrial haplogroup T1a1 as inversely associated with breast cancer risk in BRCA2 mutation carriers

Introduction: Individuals carrying pathogenic mutations in the BRCA1 and BRCA2 genes have a high lifetime risk of breast cancer. BRCA1 and BRCA2 are involved in DNA double-strand break repair, DNA alterations that can be caused by exposure to reactive oxygen species, a main source of which are mitochondria. Mitochondrial genome variations affect electron transport chain efficiency and reactive oxygen species production. Individuals with different mitochondrial haplogroups differ in their metabolism and sensitivity to oxidative stress. Variability in mitochondrial genetic background can alter reactive oxygen species production, leading to cancer risk. In the present study, we tested the hypothesis that mitochondrial haplogroups modify breast cancer risk in BRCA1/2 mutation carriers.Methods: We genotyped 22,214 (11,421 affected, 10,793 unaffected) mutation carriers belonging to the Consortium of Investigators of Modifiers of BRCA1/2 for 129 mitochondrial polymorphisms using the iCOGS array. Haplogroup inference and association detection were performed using a phylogenetic approach. ALTree was applied to explore the reference mitochondrial evolutionary tree and detect subclades enriched in affected or unaffected individuals.Results: We discovered that subclade T1a1 was depleted in affected BRCA2 mutation carriers compared with the rest of clade T (hazard ratio (HR) = 0.55; 95% confidence interval (CI), 0.34 to 0.88; P = 0.01). Compared with the most frequent haplogroup in the general population (that is, H and T clades), the T1a1 haplogroup has a HR of 0.62 (95% CI, 0.40 to 0.95; P = 0.03). We also identified three potential susceptibility loci, including G13708A/rs28359178, which has demonstrated an inverse association with familial breast cancer risk.Conclusions: This study illustrates how original approaches such as the phylogeny-based method we used can empower classical molecular epidemiological studies aimed at identifying association or risk modification effects.</p

Associations of common breast cancer susceptibility alleles with risk of breast cancer subtypes in BRCA1 and BRCA2 mutation carriers

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Evaluation of Polygenic Risk Scores for Breast and Ovarian Cancer Risk Prediction in BRCA1 and BRCA2 Mutation Carriers

$\textbf{Background:}$ Genome-wide association studies (GWAS) have identified 94 common single-nucleotide polymorphisms (SNPs) associated with breast cancer (BC) risk and 18 associated with ovarian cancer (OC) risk. Several of these are also associated with risk of BC or OC for women who carry a pathogenic mutation in the high-risk BC and OC genes $\textit{BRCA1}$ or $\textit{BRCA2}$. The combined effects of these variants on BC or OC risk for BRCA1 and BRCA2 mutation carriers have not yet been assessed while their clinical management could benefit from improved personalized risk estimates. $\textbf{Methods:}$ We constructed polygenic risk scores (PRS) using BC and OC susceptibility SNPs identified through populationbased GWAS: for BC (overall, estrogen receptor [ER]–positive, and ER-negative) and for OC. Using data from 15 252 female $\textit{BRCA1}$ and 8211 $\textit{BRCA2}$ carriers, the association of each PRS with BC or OC risk was evaluated using a weighted cohort approach, with time to diagnosis as the outcome and estimation of the hazard ratios (HRs) per standard deviation increase in the PRS. $\textbf{Results:}$ The PRS for ER-negative BC displayed the strongest association with BC risk in $\textit{BRCA1}$ carriers (HR = 1.27, 95% confidence interval [CI] = 1.23 to 1.31, $P$ = 8.2 $\times$ 10$^{-53}$). In $\textit{BRCA2}$ carriers, the strongest association with BC risk was seen for the overall BC PRS (HR = 1.22, 95% CI = 1.17 to 1.28, $P$ = 7.2 $\times$ 10$^{-20}$). The OC PRS was strongly associated with OC risk for both $\textit{BRCA1}$ and $\textit{BRCA2}$ carriers. These translate to differences in absolute risks (more than 10% in each case) between the top and bottom AR deciles of the PRS distribution; for example, the OC risk was 6% by age 80 years for $\textit{BRCA2}$ carriers at the 10th percentile of the OC PRS compared with 19% risk for those at the 90th percentile of PRS. $\textbf{Conclusions:}$ BC and OC PRS are predictive of cancer risk in $\textit{BRCA1}$ and $\textit{BRCA2}$ carriers. Incorporation of the PRS into risk prediction models has promise to better inform decisions on cancer risk management.Cancer Research U

Breast and Prostate Cancer Risks for Male BRCA1 and BRCA2 Pathogenic Variant Carriers Using Polygenic Risk Scores

Breast and prostate cancer risks; Pathogenic variantRiscos de càncer de mama i pròstata; Variants patogèniquesRiesgos de cáncer de mama y próstata; Variantes patogénicasBackground Recent population-based female breast cancer and prostate cancer polygenic risk scores (PRS) have been developed. We assessed the associations of these PRS with breast and prostate cancer risks for male BRCA1 and BRCA2 pathogenic variant carriers. Methods 483 BRCA1 and 1318 BRCA2 European ancestry male carriers were available from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). A 147-single nucleotide polymorphism (SNP) prostate cancer PRS (PRSPC) and a 313-SNP breast cancer PRS were evaluated. There were 3 versions of the breast cancer PRS, optimized to predict overall (PRSBC), estrogen receptor (ER)–negative (PRSER-), or ER-positive (PRSER+) breast cancer risk. Results PRSER+ yielded the strongest association with breast cancer risk. The odds ratios (ORs) per PRSER+ standard deviation estimates were 1.40 (95% confidence interval [CI] =1.07 to 1.83) for BRCA1 and 1.33 (95% CI = 1.16 to 1.52) for BRCA2 carriers. PRSPC was associated with prostate cancer risk for BRCA1 (OR = 1.73, 95% CI = 1.28 to 2.33) and BRCA2 (OR = 1.60, 95% CI = 1.34 to 1.91) carriers. The estimated breast cancer odds ratios were larger after adjusting for female relative breast cancer family history. By age 85 years, for BRCA2 carriers, the breast cancer risk varied from 7.7% to 18.4% and prostate cancer risk from 34.1% to 87.6% between the 5th and 95th percentiles of the PRS distributions. Conclusions Population-based prostate and female breast cancer PRS are associated with a wide range of absolute breast and prostate cancer risks for male BRCA1 and BRCA2 carriers. These findings warrant further investigation aimed at providing personalized cancer risks for male carriers and informing clinical management.The CIMBA data management and data analysis were supported by Cancer Research UK grants C12292/A20861 and PPRPGM-Nov20\100002. The research leading to these results has received funding from the Italian Association for Cancer Research (AIRC) under IG 2018 - ID. 21389 and the Italian League for the Fight Against Cancer (LILT) under IG 2019 projects, P.I. Ottini Laura and Italian Ministry of Education, Universities and Research-Dipartimenti di Eccellenza-L. 232/2016. CIMBA: GCT is a National Health and Medical Research Council (NHMRC) Research Fellow. iCOGS and OncoArray data: the European Community’s Seventh Framework Programme under grant agreement No. 223175 (HEALTH-F2-2009-223175) (COGS), Cancer Research UK (C1287/A10118, C1287/A 10710, C12292/A11174, C1281/A12014, C5047/A8384, C5047/A15007, C5047/A10692, C8197/A16565), the National Institutes of Health (NIH) (CA128978) and Post-Cancer GWAS initiative (1U19 CA148537, 1U19 CA148065 and 1U19 CA148112 - the GAME-ON initiative), the Department of Defence (W81XWH-10-1-0341), the Canadian Institutes of Health Research (CIHR) for the CIHR Team in Familial Risks of Breast Cancer (CRN-87521), and the Ministry of Economic Development, Innovation and Export Trade (PSR-SIIRI-701), Komen Foundation for the Cure, the Breast Cancer Research Foundation, and the Ovarian Cancer Research Fund. The Personalized Risk Stratification for Prevention and Early Detection of Breast Cancer (PERSPECTIVE) and PERSPECTIVE I&I projects were supported by the Government of Canada through Genome Canada and the Canadian Institutes of Health Research, the Ministry of Economy and Innovation through Genome Québec, and The Quebec Breast Cancer Foundation and the Ontario Research Fund. Breast Cancer Family Registry (BCFR): UM1 CA164920 from the National Cancer Institute (NCI). Baltic Familial Breast Ovarian Cancer Consortium (BFBOCC): Lithuania (BFBOCC-LT): Research Council of Lithuania grant SEN-18/2015. Beth Israel Deaconess Medical Center (BIDMC): Breast Cancer Research Foundation. BRCA-gene mutations and breast cancer in South African women (BMBSA): Cancer Association of South Africa (PI Elizabeth J. van Rensburg). Spanish National Cancer Centre (CNIO): Spanish Ministry of Health PI16/00440 supported by Fondo Europeo de Desarrollo Regional (FEDER) funds, the Spanish Ministry of Economy and Competitiveness (MINECO) SAF2014-57680-R and the Spanish Research Network on Rare diseases (CIBERER). City of Hope - Clinical Cancer Genomics Community Research Network (COH-CCGCRN): Research reported in this publication was supported by the NCI of the NIH under grant No. R25CA112486, and RC4CA153828 (PI: J. Weitzel) from the NCI and the Office of the Director, NIH. CONsorzio Studi ITaliani sui Tumori Ereditari Alla Mammella (CONSIT TEAM): Associazione Italiana Ricerca sul Cancro (AIRC; IG2014 No.15547) to P. Radice. Funds from Italian citizens who allocated the 5x1000 share of their tax payment in support of the Fondazione IRCCS Istituto Nazionale Tumori, according to Italian laws (INT-Institutional strategic projects ‘5x1000’) to S. Manoukian. Associazione CAOS Varese to M.G. Tibiletti. AIRC (IG2015 No.16732) to P. Peterlongo. National Centre for Scientific Research Demokritos (DEMOKRITOS): European Union (European Social Fund—ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) - Research Funding Program of the General Secretariat for Research & Technology: SYN11_10_19 NBCA. Investing in knowledge society through the European Social Fund. German Cancer Research Center (DFKZ): German Cancer Research Center. Epidemiological Study of Familial Breast Cancer (EMBRACE): Cancer Research UK Grants C1287/A10118 and C1287/A11990. D. Gareth Evans and Fiona Lalloo are supported by an National Institute for Health Research (NIHR) grant to the Biomedical Research Centre, Manchester. The Investigators at The Institute of Cancer Research and The Royal Marsden National Health Service (NHS) Foundation Trust are supported by an NIHR grant to the Biomedical Research Centre at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust. Ros Eeles and Elizabeth Bancroft are supported by Cancer Research UK Grant C5047/A8385. Ros Eeles is also supported by NIHR support to the Biomedical Research Centre at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust. Fox Chase Cancer Center (FCCC): The University of Kansas Cancer Center (P30 CA168524) and the Kansas Bioscience Authority Eminent Scholar Program. AKG was in part funded by the NCI (R01 CA214545 and R01 CA140323), The Kansas Institute for Precision Medicine (P20 GM130423), and the Kansas Bioscience Authority Eminent Scholar Program. A.K.G. is the Chancellors Distinguished Chair in Biomedical Sciences Professor. Fundación Pública Galega de Medicina Xenómica (FPGMX): FISPI05/2275 and Mutua Madrileña Foundation (FMMA). German Familial Breast Group (GC-HBOC): German Cancer Aid (grant No. 110837, Rita K. Schmutzler) and the European Regional Development Fund and Free State of Saxony, Germany (LIFE—Leipzig Research Centre for Civilization Diseases, project No. 713-241202, No. 713-241202, No. 14505/2470, and No. 14575/2470). Genetic Modifiers of cancer risk in BRCA1/2 mutation carriers (GEMO): Ligue Nationale Contre le Cancer; the Association “Le cancer du sein, parlons-en!” Award, the Canadian Institutes of Health Research for the “CIHR Team in Familial Risks of Breast Cancer” program and the French National Institute of Cancer (INCa grants 2013-1-BCB-01-ICH-1 and SHS-E-SP 18-015). Georgetown University (GEORGETOWN): the Non-Therapeutic Subject Registry Shared Resource at Georgetown University (NIH/NCI grant P30-CA051008), the Fisher Center for Hereditary Cancer and Clinical Genomics Research, and Swing Fore the Cure. Ghent University Hospital (G-FAST): Bruce Poppe is a senior clinical investigator of FWO. Mattias Van Heetvelde obtained funding from IWT. Hospital Clinico San Carlos (HCSC): Spanish Ministry of Health PI15/00059, PI16/01292, and CB-161200301 CIBERONC from ISCIII (Spain), partially supported by European Regional Development FEDER funds. Helsinki Breast Cancer Study (HEBCS): Helsinki University Hospital Research Fund, the Finnish Cancer Society and the Sigrid Juselius Foundation. Hereditary Breast and Ovarian cancer study the Netherlands (HEBON): the Dutch Cancer Society grants NKI1998-1854, NKI2004-3088, NKI2007-3756, the Netherlands Organization of Scientific Research grant NWO 91109024, the Pink Ribbon grants 110005 and 2014-187.WO76, the Biobanking and Biomolecular Resources Research Infrastructure (BBMRI) grant NWO 184.021.007/CP46 and the Transcan grant JTC 2012 Cancer 12-054. HEBON thanks the registration teams of Dutch Cancer Registry (IKNL; S. Siesling, J. Verloop) and the Dutch Pathology database (PALGA; L. Overbeek) for part of the data collection. Study of Genetic Mutations in Breast and Ovarian Cancer patients in Hong Kong and Asia (HRBCP): Hong Kong Sanatorium and Hospital, Dr Ellen Li Charitable Foundation, The Kerry Group Kuok Foundation, National Institute of Health1R 03CA130065, and North California Cancer Center. Molecular Genetic Studies of Breast- and Ovarian Cancer in Hungary (HUNBOCS): Hungarian Research Grants KTIA-OTKA CK-80745 and NKFI_OTKA K-112228. Institut Català d’Oncologia (ICO): The authors would like to particularly acknowledge the support of the Asociación Española Contra el Cáncer (AECC), the Instituto de Salud Carlos III (organismo adscrito al Ministerio de Economía y Competitividad) and “FEDER, una manera de hacer Europa” (PI10/01422, PI13/00285, PIE13/00022, PI15/00854, PI16/00563 and CIBERONC) and the Institut Català de la Salut and Autonomous Government of Catalonia (2009SGR290, 2014SGR338 and PERIS Project MedPerCan). International Hereditary Cancer Centre (IHCC): PBZ_KBN_122/P05/2004. Iceland Landspitali – University Hospital (ILUH): Icelandic Association “Walking for Breast Cancer Research” and by the Landspitali University Hospital Research Fund. INterdisciplinary HEalth Research Internal Team BReast CAncer susceptibility (INHERIT): Canadian Institutes of Health Research for the “CIHR Team in Familial Risks of Breast Cancer” program—grant No. CRN-87521 and the Ministry of Economic Development, Innovation and Export Trade—grant No. PSR-SIIRI-701. Istituto Oncologico Veneto (IOVHBOCS): Ministero della Salute and “5x1000” Istituto Oncologico Veneto grant. Portuguese Oncology Institute-Porto Breast Cancer Study (IPOBCS): Liga Portuguesa Contra o Cancro. Kathleen Cuningham Consortium for Research into Familial Breast Cancer (kConFab): The National Breast Cancer Foundation, and previously by the National Health and Medical Research Council (NHMRC), the Queensland Cancer Fund, the Cancer Councils of New South Wales, Victoria, Tasmania and South Australia, and the Cancer Foundation of Western Australia. Korean Hereditary Breast Cancer Study (KOHBRA): the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), and the National R&D Program for Cancer Control, Ministry of Health & Welfare, Republic of Korea (HI16C1127; 1020350; 1420190). Mayo Clinic (MAYO): NIH grants CA116167, CA192393 and CA176785, an NCI Specialized Program of Research Excellence (SPORE) in Breast Cancer (CA116201), and a grant from the Breast Cancer Research Foundation. McGill University (MCGILL): Jewish General Hospital Weekend to End Breast Cancer, Quebec Ministry of Economic Development, Innovation and Export Trade. Marc Tischkowitz is supported by the funded by the European Union Seventh Framework Program (2007Y2013)/European Research Council (Grant No. 310018). Modifier Study of Quantitative Effects on Disease (MODSQUAD): MH CZ—DRO (MMCI, 00209805), MEYS—NPS I—LO1413 to LF, and by Charles University in Prague project UNCE204024 (MZ). Memorial Sloane Kettering Cancer Center (MSKCC): the Breast Cancer Research Foundation, the Robert and Kate Niehaus Clinical Cancer Genetics Initiative, the Andrew Sabin Research Fund and a Cancer Center Support Grant/Core Grant (P30 CA008748). Women’s College Research Institute Hereditary Breast and Ovarian Cancer Study (NAROD): 1R01 CA149429-01. National Cancer Institute (NCI): the Intramural Research Program of the US NCI, NIH, and by support services contracts NO2-CP-11019-50, N02-CP-21013-63 and N02-CP-65504 with Westat, Inc, Rockville, MD. National Israeli Cancer Control Center (NICCC): Clalit Health Services in Israel, the Israel Cancer Association and the Breast Cancer Research Foundation (BCRF), NY. N.N. Petrov Institute of Oncology (NNPIO): the Russian Foundation for Basic Research (grants 17-54-12007, 17-00-00171 and 18-515-12007). NRG Oncology: U10 CA180868, NRG SDMC grant U10 CA180822, NRG Administrative Office and the NRG Tissue Bank (CA 27469), the NRG Statistical and Data Center (CA 37517) and the Intramural Research Program, NCI. The Ohio State University Comprehensive Cancer Center (OSUCCG): Ohio State University Comprehensive Cancer Center. Università di Pisa (PBCS): AIRC [IG 2013 N.14477] and Tuscany Institute for Tumors (ITT) grant 2014-2015-2016. South East Asian Breast Cancer Association Study (SEABASS): Ministry of Science, Technology and Innovation, Ministry of Higher Education (UM.C/HlR/MOHE/06) and Cancer Research Initiatives Foundation. Sheba Medical Centre (SMC): the Israeli Cancer Association. Swedish Breast Cancer Study (SWE-BRCA): the Swedish Cancer Society. University of Chicago (UCHICAGO): NCI Specialized Program of Research Excellence (SPORE) in Breast Cancer (CA125183), R01 CA142996, 1U01CA161032 and by the Ralph and Marion Falk Medical Research Trust, the Entertainment Industry Fund National Women’s Cancer Research Alliance and the Breast Cancer research Foundation. OIO is an American Cancer Society (ACS) Clinical Research Professor. University of California Los Angeles (UCLA): Jonsson Comprehensive Cancer Center Foundation; Breast Cancer Research Foundation. University of California San Francisco (UCSF): UCSF Cancer Risk Program and Helen Diller Family Comprehensive Cancer Center. UK Familial Ovarian Cancer Registry (UKFOCR): Cancer Research UK. University of Pennsylvania (UPENN): NIH (R01-CA102776 and R01-CA083855); Breast Cancer Research Foundation; Susan G. Komen Foundation for the cure, Basser Research Center for BRCA. Cancer Family Registry University of Pittsburg (UPITT/MWH): Hackers for Hope Pittsburgh. Victorian Familial Cancer Trials Group (VFCTG): Victorian Cancer Agency, Cancer Australia, National Breast Cancer Foundation. Women’s Cancer Program at Cedars-Sinai Medical Center (WCP): Dr Karlan is funded by the ACS Early Detection Professorship (SIOP-06-258-01-COUN) and the National Center for Advancing Translational Sciences (NCATS), Grant UL1TR000124. TN-D is a recipient of a Career Development Fellow from the National Breast Cancer Foundation (Australia, ECF-17-001)

Identification of a BRCA2-Specific modifier locus at 6p24 related to breast cancer risk

Common genetic variants contribute to the observed variation in breast cancer risk for BRCA2 mutation carriers; those known to date have all been found through population-based genome-wide association studies (GWAS). To comprehensively identify breast cancer risk modifying loci for BRCA2 mutation carriers, we conducted a deep replication of an ongoing GWAS discovery study. Using the ranked P-values of the breast cancer associations with the imputed genotype of 1.4 M SNPs, 19,029 SNPs were selected and designed for inclusion on a custom Illumina array that included a total of 211,155 SNPs as part of a multi-consortial project. DNA samples from 3,881 breast cancer affected and 4,330 unaffected BRCA2 mutation carriers from 47 studies belonging to the Consortium of Investigators of Modifiers of BRCA1/2 were genotyped and available for analysis. We replicated previously reported breast cancer susceptibility alleles in these BRCA2 mutation carriers and for several regions (including FGFR2, MAP3K1, CDKN2A/B, and PTHLH) identified SNPs that have stronger evidence of association than those previously published. We also identified a novel susceptibility allele at 6p24 that was inversely associated with risk in BRCA2 mutation carriers (rs9348512; per allele HR = 0.85, 95% CI 0.80-0.90, P = 3.9×10−8). This SNP was not associated with breast cancer risk either in the general population or in BRCA1 mutation carriers. The locus lies within a region containing TFAP2A, which encodes a transcriptional activation protein that interacts with several tumor suppressor genes. This report identifies the first breast cancer risk locus specific to a BRCA2 mutation background. This comprehensive update of novel and previously reported breast cancer susceptibility loci contributes to the establishment of a panel of SNPs that modify breast cancer risk in BRCA2 mutation carriers. This panel may have clinical utility for women with BRCA2 mutations weighing options for medical prevention of breast cancer

BRCA2 polymorphic stop codon K3326X and the risk of breast, prostate, and ovarian cancers

Background: The K3326X variant in BRCA2 (BRCA2*c.9976A&gt;T; p.Lys3326*; rs11571833) has been found to be associated with small increased risks of breast cancer. However, it is not clear to what extent linkage disequilibrium with fully pathogenic mutations might account for this association. There is scant information about the effect of K3326X in other hormone-related cancers. Methods: Using weighted logistic regression, we analyzed data from the large iCOGS study including 76 637 cancer case patients and 83 796 control patients to estimate odds ratios (ORw) and 95% confidence intervals (CIs) for K3326X variant carriers in relation to breast, ovarian, and prostate cancer risks, with weights defined as probability of not having a pathogenic BRCA2 variant. Using Cox proportional hazards modeling, we also examined the associations of K3326X with breast and ovarian cancer risks among 7183 BRCA1 variant carriers. All statistical tests were two-sided. Results: The K3326X variant was associated with breast (ORw = 1.28, 95% CI = 1.17 to 1.40, P = 5.9x10- 6) and invasive ovarian cancer (ORw = 1.26, 95% CI = 1.10 to 1.43, P = 3.8x10-3). These associations were stronger for serous ovarian cancer and for estrogen receptor–negative breast cancer (ORw = 1.46, 95% CI = 1.2 to 1.70, P = 3.4x10-5 and ORw = 1.50, 95% CI = 1.28 to 1.76, P = 4.1x10-5, respectively). For BRCA1 mutation carriers, there was a statistically significant inverse association of the K3326X variant with risk of ovarian cancer (HR = 0.43, 95% CI = 0.22 to 0.84, P = .013) but no association with breast cancer. No association with prostate cancer was observed. Conclusions: Our study provides evidence that the K3326X variant is associated with risk of developing breast and ovarian cancers independent of other pathogenic variants in BRCA2. Further studies are needed to determine the biological mechanism of action responsible for these associations

Ассоциативно-семантическая группа как языковая основа концепта

Статья посвящена описанию особой лексико-семантической парадигмы ассоциативно-семантической группы, которая является частью ассоциативно- семантического комплекса и рассматривается как языковая основа концепта. Исследование проведено с применением описательного, структурного и функционального методов.Статтю присвячено опису особливої лексико-семантичної парадигми асоціативно-семантичної групи, яка є частиною асоціативно-семантичного комплексу і являє собою мовну основу концепту. Дослідження проведено із застосуванням описового, структурного та функціонального методів.The particular lexico-semantic paradigm – associative-semantic group (ASG) which is the part of associative-semantic complex (ASC) – is investigated in the article as a linguistic base of concept. Descriptive, structural, and functional methods were used

Inheritance of deleterious mutations at both BRCA1 and BRCA2 in an international sample of 32,295 women

Background: Most BRCA1 or BRCA2 mutation carriers have inherited a single (heterozygous) mutation. Transheterozygotes (TH) who have inherited deleterious mutations in both BRCA1 and BRCA2 are rare, and the consequences of transheterozygosity are poorly understood. Methods: From 32,295 female BRCA1/2 mutation carriers, we identified 93 TH (0.3 %). "Cases" were defined as TH, and "controls" were single mutations at BRCA1 (SH1) or BRCA2 (SH2). Matched SH1 "controls" carried a BRCA1 mutation found in the TH "case". Matched SH2 "controls" carried a BRCA2 mutation found in the TH "case". After matching the TH carriers with SH1 or SH2, 91 TH were matched to 9316 SH1, and 89 TH were matched to 3370 SH2. Results: The majority of TH (45.2 %) involved the three common Jewish mutations. TH were more likely than SH1 and SH2 women to have been ever diagnosed with breast cancer (BC; p = 0.002). TH were more likely to be diagnosed with ovarian cancer (OC) than SH2 (p = 0.017), but not SH1. Age at BC diagnosis was the same in TH vs. SH1 (p = 0.231), but was on average 4.5 years younger in TH than in SH2 (p < 0.001). BC in TH was more likely to be estrogen receptor (ER) positive (p = 0.010) or progesterone receptor (PR) positive (p = 0.013) than in SH1, but less likely to be ER positive (p < 0.001) or PR positive (p = 0.012) than SH2. Among 15 tumors from TH patients, there was no clear pattern of loss of heterozygosity (LOH) for BRCA1 or BRCA2 in either BC or OC. Conclusions: Our observations suggest that clinical TH phenotypes resemble SH1. However, TH breast tumor marker characteristics are phenotypically intermediate to SH1 and SH2

Associations of common breast cancer susceptibility alleles with risk of breast cancer subtypes in BRCA1 and BRCA2 mutation carriers

Introduction: More than 70 common alleles are known to be involved in breast cancer (BC) susceptibility, and several exhibit significant heterogeneity in their associations with different BC subtypes. Although there are differences in the association patterns between BRCA1 and BRCA2 mutation carriers and the general population for several loci, no study has comprehensively evaluated the associations of all known BC susceptibility alleles with risk of BC subtypes in BRCA1 and BRCA2 carriers. Methods: We used data from 15,252 BRCA1 and 8,211 BRCA2 carriers to analyze the associations between approximately 200,000 genetic variants on the iCOGS array and risk of BC subtypes defined by estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and triple-negative- (TN) status; morphologic subtypes; histological grade; and nodal involvement. Results: The estimated BC hazard ratios (HRs) for the 74 known BC alleles in BRCA1 carriers exhibited moderate correlations with the corresponding odds ratios from the general population. However, their associations with ER-positive BC in BRCA1 carriers were more consistent with the ER-positive as