Prognostic role of progesterone receptor (PR) expression by immunohistochemistry (IHC) in relation to Oncotype recurrence scores (RS).

e11589 Background: Currently immunohistochemical distinction between Luminal A and B breast tumors are not perfect when compared gene-expression based assays. Histologic grade, Ki 67 and hormone receptor status are the major pathologic parameters used to improve our clinical decisions in distinguishing luminal tumors. It has recently been suggested that PR expression ≥ 20 % might indicate luminal A subtype Methods: Methods: We planned to examine the prognostic role of PR expression by IHC in relation to OncotypeDx recurrence scores. We analyzed pathological characteristics of 102 patients who had ER and/or PR positive, Her-2 negative breast cancer and had their tumor sample sent for OncotypeDx between 2010 and 2014 from a single institution. Results: Therecurrence scores were as follows: 60 patients had low, 33 patients had intermediate and 9 patients had high RS. Eighty-three patients hadT1 and 19 patients had T2 tumors; 19 patients had multifocal/centrictumors.Seventy three patients had node negative, 1...