SEPT9 is amplified in human breast cancer. (A) FISH labeling of SEPT9 gene (green) and HER2 gene (red) in SKBR3 breast cancer cells (left panel) and primary invasive ductal carcinoma (IDC) breast tissue (right panel). (B) Unsupervised hierarchical clustering of SEPT9 DNA copy number in human cell lines. Each block represents one cell, and 25 cells were counted for each cell line. (C) Total SEPT9 mRNA levels in the human cell lines (Additional file 1, Supplementary Table 2).