ESR1 and breast carcinoma: In this sense, TransATAC, the translational study of the Arimidex, Tamoxifen, Alone or in Combination trial (ATAC), has recently addressed the prognostic value of EP and EPclin for 10-year distant recurrence risk in postmenopausal women with ER+/HER2- breast carcinomas, and compared their prognostic ability with that of the Oncotype DX RS [11].