In a previous study, we have determined the promoter methylation status of six tumor suppressor genes, comprising CCND2 (cyclin D2), DAPK1 (death-associated protein kinase 1), GSTP1 (glutathione S-transferase P1), HIN-1 (high in normal-1), MGMT (O6-methylguanine-DNA methyltransferase) and RASSF1A (Ras association domain family member 1), in tumor, tumor-adjacent and tumor-distant tissues from the same breast cancer patients by methylation-sensitive high resolution melting analysis [45]. The gene discussed is RASSF1; the disease is breast cancer.