In breast cancer, TMEFF2 promoter methylation increases progressively along the potential developmental path of invasive ductal carcinoma (IDC) from the preinvasive lesions like flat epithelial atypia (FEA), atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS) [29,30]. The gene discussed is TMEFF2; the disease is breast cancer.