The objective of their study was to evaluate promoter methylation of a panel of 12 BC-related genes (APC, BRCA1, CCND2, CDH1, ER1, GSTP1, HIN1, P16, RARβ, RASSF1, SFRP1, and TWIST) in the serum of postmenopausal women, including BC cases with lymph node-positive disease, BC cases with lymph node-negative disease, and women with benign breast diseases. Here, GSTP1 is linked to breast cancer.