PCNA and breast cancer: Recently, flap endonuclease 1 (FEN1) was proven to interact with DNMT3A through proliferating cell nuclear antigen (PCNA) to suppress miR-200a-5p expression mediated by methylation, which resulted in increased levels of hepatocyte growth factor (MET) and epidermal growth factor receptor (EGFR) and thus elevating proliferation of BC cells [128].