Average over-/underexpression frequencies and mutation rates of chromatin factor families. Top: Averages were calculated by summing the frequencies of overexpression or underexpression, or number of mutations per kilobase for each gene and dividing by the total number of genes in the family. The list of 359 chromatin factors is composed of the 441 genes listed in Additional file 1: Table S1 from which histones and histone chaperones were removed. Numbers were also calculated for five independent sets of 359 random genes for comparison. Log2(mRNA tumor/matched control) cut-offs of 2 and -2 were used for over- and underexpression, respectively, for better separation and comparison of transcription profiles.