RAD51 and breast cancer: Depletion of homologous recombinational repair and epigenetic repression of RAD51 paralogues including XRCC2 are accompanied by increased expression of EZH2. Over-expression of EZH2 protein between 40%-75% is found in breast cancer and EZH2 mRNA is up-adjusted, about 7.5-fold (Paulicova et al., 2013; Chang and Hung, 2012; Volkel et al., 2015).