It would therefore be of interest to further compare methylation of CDH13, TWIST1, and WIF1 in DCIS, normal epithelium adjacent to DCIS, and normal epithelium from healthy breast (such as the contralateral breast) in an independent cohort to determine whether methylation of these genes observed in normal samples is a disease-related event. This evidence concerns the gene WIF1 and ductal breast carcinoma in situ.