Figure 2.

Hierarchical clustering of 69 tumor samples with available gene expression data. Clustering was based on 364 genes from the intrinsic gene list published by Sørlie and colleagues [9] that matched our cDNA clones. Colored boxes indicate classification of each tumor into subtypes/subgroups. Filled or open boxes indicate the percentage of cells in each tumor positive for the CD44⁺/CD24^- and CD44^-/CD24⁺ phenotypes as determined by immunohistochemistry. SR, steroid receptor. Hu classification, Hu and colleagues [10].