We predict that patients with luminal-type (ER+/PR+) breast tumors that express this 'phospho-PR' gene signature exist (see Figure 1A and Additional file 9) and that this subset, if identified early, could benefit from endocrine therapies that include the use of newer highly selective antiprogestins (that is, ZK 230211, CDB-4124), perhaps in combination with currently used antiestrogens and/or growth factor pathway inhibition. This evidence concerns the gene ESR1 and breast neoplasm.