GSTP1 and ductal breast carcinoma in situ: Among all DCIS, RASSF1A methylation was present in 90% (72/80) of samples, CDH13 in 53.8% (43/80), MAL in 49.4% (39/79), APC in 48.8% (39/80), WIF1 in 48.8% (39/80), GSTP1 in 47.5% (38/80), TWIST1 in 40.7% (33/81), RARβ in 37% (30/81), and FOXC1 methylation in 11.3% (9/80) of samples.