Several genes including GSTP1 (Glutathione S-transferase P1), RASSF1A (Ras association domain family 1A), and RARβ2 (Retinoic acid receptor β2) have been identified as methylated genes in breast cancer (Yamamoto et al. 2012; Arai et al. 2006; Miyake et al. 2012) but each of these markers is not always specific to breast cancer and several markers have been used in various combinations. The gene discussed is GSTP1; the disease is breast carcinoma.