RUNX3 and SOX9, for example, are silenced in BC in at least 70% of the analysed samples [193, 194]; RUNX3 turned out to be a good candidate for the analysis of BC recurrence and development [195, 196], while SOX9 is part of a list of 26 hypermethylated genes in BC-derived tissues [194]. The gene discussed is SOX9; the disease is breast cancer.