While we observed DNA methylation in exon 1 of the SFRP1 gene in 100% of the DCIS and IDC samples we examined, methylation in the promoter region of SFRP1 has been reported to occur in approximately 68% of high-grade DCIS and invasive breast cancers [7,40]. Here, SFRP1 is linked to ductal breast carcinoma in situ.