Fig. 1.

Clustering patient data is more difficult than cell-based data. Partial views of dendrograms constructed from hierarchical clustering of the TCGA Breast Cancer expression data (top) and the yeast expression data (from Spellman et al.¹¹). The dendograms suggest that it is easier to select a threshold to prune the tree and generate potentially meaningful clusters for the yeast data but not so for the breast cancer data.