For example, Park et al. reported distinct promoter CpG island methylation among breast cancer subtypes at 12 loci related to tumor progression, including APC, DLEC1, GRIN2B, GSTP1, HOXA1, MT1G, RARB, RASSF1A, RUNX3, SCGB3A1, SFRP1, and TMEFF243. This evidence concerns the gene SFRP1 and breast cancer.