Breast Cancer Res Treat (2012) 135:49–58 55 Fig. 3 Unsupervised hierarchical clustering of copy number changes in 21 breast cancer related genes in 106 male breast cancer patients. The identiﬁed clusters of patients (horizontal) are depicted in different colors Fig. 4 Kaplan–Meier survival curves with corresponding p values (log rank) according to 1 or more gained genes, MED1 ([1.3), HER2 ([1.3), CCND1 ampliﬁcation ([2.0), copy number gain of all analyzed genes located on chromosome 17 and cluster A versus cluster B CCND1 and MTDH were the genes which most fre- quently showed copy number gain (49 and 46 %, respec- tively), and often had ampliﬁcation, indicating that these genes probably play an important role in male breast car- cinogenesis. CCND1 encodes for cyclin D1, which is a cell cycle protein driving cell cycle progression through the G1 123