RAD21 and breast cancer: On the other hand, we have also clearly demonstrated that epigenetic field defects do not happen randomly in the genome: binding sites of transcription factors important in specifying chromatin architecture, notably members of the PRC2 complex (EZH2, SUZ12), CTCF and RAD21, were all observed to acquire DNA methylation in normal cells adjacent to breast cancers, and to exhibit even further DNAm increases in the actual cancer.