Validation of the marker gene expression by RT-PCR. Relative expression is shown in Box - Whisker - Plots. Gray columns show a 50% range of the data surrounding the median; black lines within each column mark the median; circles mark outliers. Significance was calculated with the Mann-Whitney-U test (P < = 0.05*, P < = 0.01**, P < = 0.001 three stars). A: Panel of the murine samples. Controls are transgenic mice before lactation (H). Months are calculated from the start of lactation (2 m = 2 months; 3 m = 3 months; 4 m = 4 months; 5 m = 5 months; IDC = invasive ductal carcinoma). Each group contains 7 samples. B: Panel of human samples. Controls are healthy tissues from reduction plastics (H).