ESR1 and breast cancer: Expression profiling of 453 miRNAs from 29 early-stage BC cases resulted in the identification of the miRNA signatures associated with the ER status (miR-342, miR-299, miR-217, miR-190, miR-135b, miR-218), PR status (miR-520g, miR-377, miR-527-518a, miR-520f-520c) and HER2/neu (miR-520d, miR-181c, miR-320c, miR-376b, miR-30e).