CCNE1 and breast cancer: The evidence in this study supported that overexpression of CDR1as can also reverse the enhancement on chemosensitivity of 5‐FU‐resistant BC cells caused by overexpression of miR‐7 and CDR1as may regulate chemosensitivity of 5‐FU‐resistant BC cells by inhibiting miR‐7 to regulate CCNE1.