Figure 1. ERBB2 and TOP2α maintain the copy number in feline mammary tumors. (a-b) Fold change of ERBB2 (a) and TOP2α (b) DNA copy number in feline mammary tumors (FMT) analyzed by real-time qPCR and compared with a disease-free tissue (DFT) sample collected from the same animal (control). The percentage of tumors showing an increased, maintained or decreased gene copy number of ERBB2 (a) and TOP2α (b) is presented in the upper right corner of each graph. Values are mean ± SD of three replicates. *p≤0.05, **p≤0.01, ***p≤0.001, ****p≤0.0001 were determined by Student’s t-test.