Table 1. Overview of the experimental data sets.

name	number of samples	number of genes		in %	original publication
Leukemia	47/25	3571	1445	40.46	[19]
Lymphoma	58/19	7129	1739	24.39	[20]
Breast cancer	44/34	4997	54	1.08	[17]
Prostate 1	50/52	6033	2393	35.26	[21]
Prostate 2	41/62	42129	595	1.40	[22]

^aFor the determination of the number of differentially expressed genes () we use a t-test (from the R-package stats) and an FDR correction [15] (R-package qvalue). We count all genes with a q-value below 0.05.