Johnson, NicholaDudbridge, FrankOrr, NickGibson, LornaJones, Michael ESchoemaker, Minouk JFolkerd, Elizabeth JHaynes, Ben PHopper, John LSouthey, Melissa CDite, Gillian SApicella, CarmelSchmidt, Marjanka KBroeks, AnnegienVan’t Veer, Laura JAtsma, FemkeMuir, KennethLophatananon, ArtitayaFasching, Peter ABeckmann, Matthias WEkici, Arif BRenner, Stefan PSawyer, ElinorTomlinson, IanKerin, MichaelMiller, NicolaBurwinkel, BarbaraMarme, FrederikSchneeweiss, AndreasSohn, ChristofGuénel, PascalTruong, ThereseCordina, EmilieMenegaux, FlorenceBojesen, Stig ENordestgaard, Børge GFlyger, HenrikMilne, RogerZamora, M PilarArias Perez, Jose IgnacioBenitez, JavierBernstein, LeslieAnton-Culver, HodaZiogas, ArgyriosClarke Dur, ChristinaBrenner, HermannMüller, HeikoArndt, VolkerDieffenbach, Aida KarinaMeindl, AlfonsHeil, JoergBartram, Claus RSchmutzler, Rita KBrauch, HiltrudJustenhoven, ChristinaKo, Yon-DschunNevanlinna, HeliMuranen, Taru AAittomäki, KristiinaBlomqvist, CarlMatsuo, KeitaroDörk, ThiloBogdanova, Natalia VAntonenkova, Natalia NLindblom, AnnikaMannermaa, ArtoKataja, VesaKosma, Veli-MattiHartikainen, Jaana MChenevix-Trench, GeorgiaBeesley, JonathanWu, Anna HVan den Berg, DavidTseng, Chiu-ChenLambrechts, DietherSmeets, DominiekNeven, PatrickWildiers, HansChang-Claude, JennyRudolph, AnjaNickels, StefanFlesch-Janys, DieterRadice, PaoloPeterlongo, PaoloBonanni, BernardoPensotti, ValeriaCouch, Fergus JOlson, Janet EWang, XianshuFredericksen, ZacharyPankratz, Vernon SGiles, Graham GSeveri, GianlucaBaglietto, LauraHaiman, ChrisSimard, JacquesGoldberg, Mark SLabrèche, FranceDumont, MartineSoucy, PennyTeo, SooYip, Cheng HarPhuah, Sze YeeCornes, Belinda KKristensen, Vessela NGrenaker Alnæs, GretheBørresen-Dale, Anne-LiseZheng, WeiWinqvist, RobertPylkäs, KatriJukkola-Vuorinen, ArjaGrip, MerviAndrulis, Irene LKnight, Julia AGlendon, GordMulligan, Anna MarieDevillee, PeterFigueroa, JonineChanock, Stephen JLissowska, JolantaSherman, Mark EHall, PerSchoof, NilsHooning, MaartjeHollestelle, AntoinetteOldenburg, Rogier ATilanus-Linthorst, MadeleineLiu, JianjunCox, AngieBrock, Ian WReed, Malcolm WRCross, Simon SBlot, WilliamSignorello, Lisa BPharoah, Paul DPDunning, Alison MShah, MitulKang, DaeheeNoh, Dong-YoungPark, Sue KChoi, Ji-YeobHartman, MikaelMiao, HuiLim, Wei YenTang, AnthonyHamann, UteFörsti, AstaRüdiger, ThomasUlmer, Hans UlrichJakubowska, AnnaLubinski, JanJaworska-Bieniek, KatarzynaDurda, KatarzynaSangrajrang, SuleepornGaborieau, ValerieBrennan, PaulMcKay, JamesSlager, SusanToland, Amanda EVachon, CelineYannoukakos, DrakoulisShen, Chen-YangYu, Jyh-CherngHuang, Chiun-ShengHou, Ming-FengGonzález-Neira, AnnaTessier, Daniel CVincent, DanielBacot, FrancoisLuccarini, CraigDennis, JoeMichailidou, KyriakiBolla, Manjeet KWang, JeanEaston, Douglas FGarcía-Closas, MontserratDowsett, MitchAshworth, AlanSwerdlow, Anthony JPeto, Juliandos Santos Silva, IsabelFletcher, Olivia2015-09-012014Johnson, N., F. Dudbridge, N. Orr, L. Gibson, M. E. Jones, M. J. Schoemaker, E. J. Folkerd, et al. 2014. “Genetic variation at CYP3A is associated with age at menarche and breast cancer risk: a case-control study.” Breast Cancer Research : BCR 16 (3): R51. doi:10.1186/bcr3662. http://dx.doi.org/10.1186/bcr3662.1465-5411http://nrs.harvard.edu/urn-3:HUL.InstRepos:21459876Introduction: We have previously shown that a tag single nucleotide polymorphism (rs10235235), which maps to the CYP3A locus (7q22.1), was associated with a reduction in premenopausal urinary estrone glucuronide levels and a modest reduction in risk of breast cancer in women age ≤50 years. Methods: We further investigated the association of rs10235235 with breast cancer risk in a large case control study of 47,346 cases and 47,570 controls from 52 studies participating in the Breast Cancer Association Consortium. Genotyping of rs10235235 was conducted using a custom Illumina Infinium array. Stratified analyses were conducted to determine whether this association was modified by age at diagnosis, ethnicity, age at menarche or tumor characteristics. Results: We confirmed the association of rs10235235 with breast cancer risk for women of European ancestry but found no evidence that this association differed with age at diagnosis. Heterozygote and homozygote odds ratios (ORs) were OR = 0.98 (95% CI 0.94, 1.01; P = 0.2) and OR = 0.80 (95% CI 0.69, 0.93; P = 0.004), respectively (Ptrend = 0.02). There was no evidence of effect modification by tumor characteristics. rs10235235 was, however, associated with age at menarche in controls (Ptrend = 0.005) but not cases (Ptrend = 0.97). Consequently the association between rs10235235 and breast cancer risk differed according to age at menarche (Phet = 0.02); the rare allele of rs10235235 was associated with a reduction in breast cancer risk for women who had their menarche age ≥15 years (ORhet = 0.84, 95% CI 0.75, 0.94; ORhom = 0.81, 95% CI 0.51, 1.30; Ptrend = 0.002) but not for those who had their menarche age ≤11 years (ORhet = 1.06, 95% CI 0.95, 1.19, ORhom = 1.07, 95% CI 0.67, 1.72; Ptrend = 0.29). Conclusions: To our knowledge rs10235235 is the first single nucleotide polymorphism to be associated with both breast cancer risk and age at menarche consistent with the well-documented association between later age at menarche and a reduction in breast cancer risk. These associations are likely mediated via an effect on circulating hormone levels.en-USJournal Article2015-09-0110.1186/bcr3662