Figure 1

Unsupervised analysis of the Q-RT-PCR expression data by pairwise hierarchical clustering. 12 distinct subclasses were defined from the observed gene clusters. The luminal A/B, normal-like, ERBB2 and basal tumour subsets were identified according to gene expression signatures that have been previously reported to specify these molecular subtypes [2-4]. Subgroups 7 (SG7) and 12 (SG12) are also indicated.