These genes were chosen because methylation of the genes have previously been identified as important in invasive breast cancer by The Cancer Genome Atlas Network (TCGA) [12] and/or associated with prognosis in DCIS (APC[5], CDH1[6], FOXC1[7], GSTP1[9], RARβ[5], RASSF1A[7]) or invasive carcinoma (BRCA1[13],[14], CDH13[15], MAL[16], TWIST1[17], WIF1[18]). This evidence concerns the gene GSTP1 and ductal breast carcinoma in situ.