In addition, the hypermethylation of tumor suppressor genes (WIF1, SOX17, ADAMTSL2, SLIT3, GATA5, and WNT9A) and hypomethylation of oncogenes (MSH2, MSH3, CHK1, and CHK2) identified in this study have already been previously reported in colon, prostate, lung and breast tumors [13–16]. The gene discussed is CHEK1; the disease is breast neoplasm.