The enrichment degree of these 5 genes on biotin-labeled miR-4324 mimic was identified by RNA pull-down, and the expression level of FEN1 in miR-4324 mimic group increased the most compared with other genes (Fig. 3B). FEN1 has been extensively studied and identified as a tumor promoter in breast cancer [12, 17] and hepatocellular cancer [18]. This evidence concerns the gene FEN1 and breast cancer.