Abstract
Unambiguous classification of BRCA1 and BRCA2 variants of uncertain significance (VUS) is a challenging task that vexes health care providers and has profound implications for patients and their family members. Numerous VUS have been described to date, which await assessment of their functional, hence clinical, impact. As a result of a routine BRCA1/BRCA2 mutational screening, we identified a previously unreported BRCA1 sequence alteration [c.5178G>A (V1687I)] in a patient diagnosed with early onset triple negative breast cancer. The sequence alteration falls in the invariant THV motif of the BRCT domain. To investigate its significance, we applied an integrated approach that, in addition to genetic and histopathological data, included in silico analyses, comparative structural modeling and verification of BRCT-mediated interactions. In line with web-based algorithms that predicted the benign nature of BRCA1 V1687I, the three-dimensional model of the BRCA1 V1687I BRCT domain did not reveal any major structural changes relative to its wild-type counterpart, thus suggesting that BRCA1 V1687I has a negligible impact on both the local architecture and the overall stability of the protein. Consistently, the BRCA1 V1687I protein was properly expressed and localized to the nucleus, and it was still capable of binding three BRCT-interacting, DNA damage response, and repair partner proteins, namely BRIP1/FANCJ, CtIP, and Abraxas. Our collected evidence suggests that, although occurring in a highly conserved region, the BRCA1 V1687I variant is likely a benign sequence alteration.
This is a preview of subscription content, log in via an institution to check access.
References
Domchek S, Weber BL (2008) Genetic variants of uncertain significance: flies in the ointment. J Clin Oncol 26(1):16–17. doi:10.1200/JCO.2007.14.4154
Spurdle AB (2010) Clinical relevance of rare germline sequence variants in cancer genes: evolution and application of classification models. Curr Opin Genet Dev 20(3):315–323. doi:10.1016/j.gde.2010.03.009
Goldgar DE, Easton DF, Deffenbaugh AM, Monteiro AN, Tavtigian SV, Couch FJ (2004) Integrated evaluation of DNA sequence variants of unknown clinical significance: application to BRCA1 and BRCA2. Am J Hum Genet 75(4):535–544. doi:10.1086/424388S0002-9297(07)62706-2
Chenevix-Trench G, Healey S, Lakhani S, Waring P, Cummings M, Brinkworth R, Deffenbaugh AM, Burbidge LA, Pruss D, Judkins T, Scholl T, Bekessy A, Marsh A, Lovelock P, Wong M, Tesoriero A, Renard H, Southey M, Hopper JL, Yannoukakos K, Brown M, Easton D, Tavtigian SV, Goldgar D, Spurdle AB (2006) Genetic and histopathologic evaluation of BRCA1 and BRCA2 DNA sequence variants of unknown clinical significance. Cancer Res 66(4):2019–2027. doi:10.1158/0008-5472.CAN-05-3546
Iversen ES Jr, Couch FJ, Goldgar DE, Tavtigian SV, Monteiro AN (2011) A computational method to classify variants of uncertain significance using functional assay data with application to BRCA1. Cancer Epidemiol Biomarkers Prev 20(6):1078–1088. doi:10.1158/1055-9965.EPI-10-1214
Brzovic PS, Meza JE, King MC, Klevit RE (2001) BRCA1 RING domain cancer-predisposing mutations Structural consequences and effects on protein–protein interactions. J Biol Chem 276(44):41399–41406. doi:10.1074/jbc.M106551200M106551200
Williams RS, Green R, Glover JN (2001) Crystal structure of the BRCT repeat region from the breast cancer-associated protein BRCA1. Nat Struct Biol 8(10):838–842. doi:10.1038/nsb1001-838nsb1001-838
Williams RS, Chasman DI, Hau DD, Hui B, Lau AY, Glover JN (2003) Detection of protein folding defects caused by BRCA1-BRCT truncation and missense mutations. J Biol Chem 278(52):53007–53016. doi:10.1074/jbc.M310182200M310182200
Wu LC, Wang ZW, Tsan JT, Spillman MA, Phung A, Xu XL, Yang MC, Hwang LY, Bowcock AM, Baer R (1996) Identification of a RING protein that can interact in vivo with the BRCA1 gene product. Nat Genet 14(4):430–440
Hashizume R, Fukuda M, Maeda I, Nishikawa H, Oyake D, Yabuki Y, Ogata H, Ohta T (2001) The RING heterodimer BRCA1-BARD1 is a ubiquitin ligase inactivated by a breast cancer-derived mutation. J Biol Chem 276(18):14537–14540
Cantor S, Drapkin R, Zhang F, Lin Y, Han J, Pamidi S, Livingston DM (2004) The BRCA1-associated protein BACH1 is a DNA helicase targeted by clinically relevant inactivating mutations. Proc Natl Acad Sci USA 101(8):2357–2362
Yu X, Wu LC, Bowcock AM, Aronheim A, Baer R (1998) The C-terminal (BRCT) domains of BRCA1 interact in vivo with CtIP, a protein implicated in the CtBP pathway of transcriptional repression. J Biol Chem 273(39):25388–25392
Wang B, Matsuoka S, Ballif BA, Zhang D, Smogorzewska A, Gygi SP, Elledge SJ (2007) Abraxas and RAP80 form a BRCA1 protein complex required for the DNA damage response. Science 316(5828):1194–1198
Manke IA, Lowery DM, Nguyen A, Yaffe MB (2003) BRCT repeats as phosphopeptide-binding modules involved in protein targeting. Science 302(5645):636–639
Malacrida S, Agata S, Callegaro M, Casella C, Barana D, Scaini MC, Manoukian S, Oliani C, Radice P, Barile M, Menin C, D’Andrea E, Montagna M (2008) BRCA1 p.Val1688del is a deleterious mutation that recurs in breast and ovarian cancer families from Northeast Italy. J Clin Oncol 26(1):26–31. doi:10.1200/JCO.2007.13.2118
De Nicolo A, Parisini E, Zhong Q, Dalla Palma M, Stoeckert KA, Domchek SM, Nathanson KL, Caligo MA, Vidal M, Cusick ME, Garber JE (2009) Multimodal assessment of protein functional deficiency supports pathogenicity of BRCA1 pV1688del. Cancer Res 69(17):7030–7037. doi:10.1158/0008-5472.CAN-09-1440
Cortesi L, Turchetti D, Marchi I, Fracca A, Canossi B, Rachele B, Silvia R, Rita PA, Pietro T, Massimo F (2006) Breast cancer screening in women at increased risk according to different family histories: an update of the Modena Study Group experience. BMC Cancer 6:210. doi:10.1186/1471-2407-6-210
Sali A, Blundell TL (1993) Comparative protein modelling by satisfaction of spatial restraints. J Mol Biol 234(3):779–815. doi:10.1006/jmbi.1993.1626
De Nicolo A, Tancredi M, Lombardi G, Flemma CC, Barbuti S, Di Cristofano C, Sobhian B, Bevilacqua G, Drapkin R, Caligo MA (2008) A novel breast cancer-associated BRIP1 (FANCJ/BACH1) germ-line mutation impairs protein stability and function. Clin Cancer Res 14(14):4672–4680. doi:10.1158/1078-0432.CCR-08-0087
Yu X, Baer R (2000) Nuclear localization and cell cycle-specific expression of CtIP, a protein that associates with the BRCA1 tumor suppressor. J Biol Chem 275(24):18541–18549
Karchin R, Monteiro AN, Tavtigian SV, Carvalho MA, Sali A (2007) Functional impact of missense variants in BRCA1 predicted by supervised learning. PLoS Comput Biol 3(2):e26. doi:10.1371/journal.pcbi.0030026
Giannini G, Capalbo C, Ottini L, Buffone A, De Marchis L, Margaria E, Vitolo D, Ricevuto E, Rinaldi C, Zani M, Ferraro S, Marchetti P, Cortesi E, Frati L, Screpanti I, Gulino A (2008) Clinical classification of BRCA1 DNA missense variants: H1686Q is a novel pathogenic mutation occurring in the ontogenetically invariant THV motif of the N-terminal BRCT domain. J Clin Oncol 26(25):4212–4214. doi:10.1200/JCO.2008.18.2089 (author reply 4214–4215)
Bauer KR, Brown M, Cress RD, Parise CA, Caggiano V (2007) Descriptive analysis of estrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and HER2-negative invasive breast cancer, the so-called triple-negative phenotype: a population-based study from the California cancer Registry. Cancer 109(9):1721–1728. doi:10.1002/cncr.22618
Larkin MA, Blackshields G, Brown NP, Chenna R, McGettigan PA, McWilliam H, Valentin F, Wallace IM, Wilm A, Lopez R, Thompson JD, Gibson TJ, Higgins DG (2007) Clustal W and Clustal X version 2.0. Bioinformatics 23(21):2947–2948. doi:10.1093/bioinformatics/btm404
Gouet P, Courcelle E, Stuart DI, Metoz F (1999) ESPript: analysis of multiple sequence alignments in PostScript. Bioinformatics 15(4):305–308
Acknowledgments
We are grateful to the patients and their families for their collaboration. A.D.N. wishes to thank Dr. D. M. Livingston (Dana-Farber Cancer Institute, Boston, MA, USA) for financial support, Dr. V. Joukov (Dana-Farber Cancer Institute, Boston, MA, USA) for helpful discussions, and Dr. C. Colin (Dana-Farber Cancer Institute, Boston, MA, USA) for assistance with cell irradiation experiments. This work was, in part, supported by a PRIN 2008 grant (2008RFCMH) from the Ministero dell'Istruzione, dell'Universita' e della Ricerca (MIUR) and by funds from the Associazione Angela Serra per la Ricerca sul Cancro.
Conflict of interest
The authors declare that they have no conflict of interest.
Author information
Authors and Affiliations
Corresponding authors
Additional information
Laura Cortesi and Arcangela De Nicolo have contributed equally to this study.
Rights and permissions
About this article
Cite this article
Cortesi, L., De Nicolo, A., Medici, V. et al. Collective evidence supports neutrality of BRCA1 V1687I, a novel sequence variant in the conserved THV motif of the first BRCT repeat. Breast Cancer Res Treat 134, 435–441 (2012). https://doi.org/10.1007/s10549-012-2052-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10549-012-2052-2