Hierarchical cluster analysis based on the collection of gene signatures of 35 anticancer compounds (55 treatment samples). In total, 3237 probe sets were used for clustering. The values in the heatmap are the logarithm of sample‐to‐control ratio of intensity values. Neither normalizing nor scaling was carried out. 17‐AAG, 17‐N‐allylamino‐17‐demethoxygeldanamycin; 5‐FU, 5‐fluorouracil. Green, downregulated genes; red, upregulated genes.