Epigenetic inactivation of RASSF1A by hypermethylation of CpG islands in the promoter region [NC_000075.5 (107,453,580–107,454,373)] is observed in a considerable proportion of cancers and is associated with clinicopathological factors in various types of cancers, including breast cancer (see review [10]). The gene discussed is RASSF1; the disease is cancer.