The miRNA signatures generated for ER status (miR-342, miR-299, miR-217, miR-190, miR-135b, miR-218), for PR status (miR-520g, miR-377, miR-527-518a, miR-520f-520c) and for HER2/neu status (miR-520d, miR-181c, miR-302c, miR-376b, miR-30e) include miRNAs that have previously been identified as dysregulated in breast cancer and other cancers [7,9,37-43] and involved in the regulation of cell functions such as growth, apoptosis, migration and invasion [38,42,43]. This evidence concerns the gene PGR and breast cancer.