Mutations are distributed unevenly across the cancer genome and mutation rates across genomic regions are highly heterogeneous [12] due to genomic and epigenetic features including cytosine methylation [13], replication timing [14], tri-nucleotide/penta-nucleotide context composition [5], transcription factor binding, chromatin organization [15], gene expression levels [16], orientation of the DNA minor groove around nucleosomes [17], CTCF binding [18] and gene body features such as introns and exons [19]. The gene discussed is CTCF; the disease is cancer.