Tumor-suppressor genes with aberrant methylation in breast cancers include ARHI [3,4], RASSF1A [5], HIN-1 [6], the retinoic acid receptor II gene (RARβ2) [7], hMLH1 [8], 14-3-3 σ [9], RIZ1 [10], p16 [11], the E-cadherin gene [12], PTEN [13], and BRCA1 [14]. The gene discussed is RASSF1; the disease is breast cancer.