DNMT1 and breast cancer: For example, piR-823 was reported to increase the expression of DNMTs including DNMT1, DNMT3A, and DNMT3B, and promote DNA methylation level of the adenomatous polyposis coli (APC) gene, a tumor suppressor, thereby motivating WNT signaling pathway and inducing the formation of cancer cell stemness (CSCs) in the luminal subtype of BC cells, ultimately contributing to BC tumorigenesis 77.