Breast Cancer Res Treat (2012) 135:49–58 DOI 10.1007/s10549-012-2051-3 P R E C L I N I C A L S T U D Y Oncogene ampliﬁcation in male breast cancer: analysis by multiplex ligation-dependent probe ampliﬁcation Robert Kornegoor • Cathy B. Moelans • Anoek H. J. Verschuur-Maes • Marieke C. H. Hogenes • Peter C. de Bruin • Joost J. Oudejans • Luigi Marchionni • Paul J. van Diest Received: 22 December 2011 / Accepted: 26 March 2012 / Published online: 13 April 2012 The Author(s) 2012. This article is published with open access at Springerlink.com Abstract Gene ampliﬁcation is an important mechanism for oncogene activation, a crucial step in carcinogenesis. Compared to female breast cancer, little is known on the genetic makeup of male breast cancer, because large series are lacking. Copy number changes of 21 breast cancer related genes were studied in 110 male breast cancers using multiplex ligation-dependent probe ampliﬁcation. A ratio of [1.3 was regarded indicative for gene copy number gain and a ratio [2.0 for gene ampliﬁcation. Data were correlated with Electronic supplementary material The online version of this article (doi:10.1007/s10549-012-2051-3) contains supplementary material, which is available to authorized users. R. Kornegoor C. B. Moelans A. H. J. Verschuur-Maes P. J. van Diest Department of Pathology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands M. C. H. Hogenes Laboratory for Pathology East Netherlands, Burgemeester Edo Bergsmalaan 1, 7512 AD Enschede, The Netherlands P. C. de Bruin Department of Pathology, St. Antonius Hospital, Koekoekslaan 1, 3435 CM Nieuwegein, The Netherlands J. J. Oudejans Department of Pathology, Diakonessenhuis, Bosboomstraat 1, 3582 KE Utrecht, The Netherlands L. Marchionni Johns Hopkins University, 1550 Orleans Street, Baltimore, MD, USA P. J. van Diest (&) Department of Pathology, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, The Netherlands e-mail: p.j.vandiest@umcutrecht.nl clinicopathological features, prognosis and 17 genes were compared with a group of female breast cancers. Gene copy number gain of CCND1, TRAF4, CDC6 and MTDH was seen in[40 % of the male breast cancer cases, with also frequent ampliﬁcation. The number of genes with copy number gain and several single genes were associated with high grade, but only CCND1 ampliﬁcation was an independent predictor of adverse survival in Cox regression (p = 0.015; hazard ratio 3.0). In unsupervised hierarchical clustering a distinctive group of male breast cancer with poor prognosis (p = 0.009; hazard ratio 3.4) was identiﬁed, characterized by frequent CCND1, MTDH, CDC6, ADAM9, TRAF4 and MYC copy number gain. Compared to female breast cancers, EGFR (p = 0.005) and CCND1 (p = 0.041) copy number gain was more often seen in male breast cancer, while copy number gain of EMSY (p = 0.004) and CPD (p = 0.001) and ampliﬁcation in general was less frequent. In conclusion, several female breast cancer genes also seem to be important in male breast carcinogenesis. However, there are also clear differences in copy number changes between male and female breast cancers, pointing toward differences in carcinogenesis between male and female breast cancer and emphasizing the importance of identifying biomarkers and therapeutic agents based on research in male breast cancer. In addition CCND1 ampliﬁcation seems to be an independent prognosticator in male breast cancer. Keywords Breast cancer Male MLPA Ampliﬁcation Copy number Survival Introduction Gene ampliﬁcation is important in the development and progression of cancer and could serve as a potential 123