We then studied which tumor suppressor gene could be suppressed by LncCCAT1 through upregulating DNMT1 in breast cancer by screening 14 genes, which were not only downregulated in LncCCAT1-overexpressing esophageal squamous cancer cells but can also be methylated in the promoter regions (MethPrimer, http://www.urogene.org/methprimer/index1.html). This evidence concerns the gene DNMT1 and breast carcinoma.