RASSF2, one of the six Ras-association domain family of genes, was found to located at 20p13 and methylation of the RASSF2 promoter was an early and a frequent event in a series of epithelial-derived tumours including breast cancer, colorectal cancer, non-small cell lung cancer, nasopharyngeal cancer et al. [37, 38]. Here, RASSF2 is linked to breast cancer.