DNMT1 and breast cancer: To investigate the role of the SOX5/DNMT1/p21 pathway in the cellular processes of BC cells, we first constructed a p21 overexpression vector (pcDH-p21) based on the pcDNA-3.1 vector and transfected it into T24 and J82 cells qPCR and western blot analysis revealed that pcDH-p21 significantly increased p21 expression in both cell lines (Figure 6C–E).