Microarray analysis of murine samples. A: Supervised hierarchical clustering using 173 probe sets (= 140 genes) overexpressed in mice taken 2-3 months after lactation and in IDC of WAP-TNP8 mice. Each row represents a probe set and each column a sample. The length and the subdivision of branches display the relation of the samples based on their expression. Each group contains samples obtained from five mice. The time point of determination of gene expression was calculated as months after lactation (1 month, 2 months,...). As a positive control IDCs (Tumor) were used. Additionally, wild type (WT = Balb/C) mice and mice without lactation (neg. contr) were used as negative controls. Red indicates upregulation, green downregulation, and black no change. B: Supervised hierarchical clustering of the murine samples using the seven marker genes clearly distinguishes between control samples and malignant samples.