Prognostic values of negative estrogen or progesterone receptor expression in patients with luminal B HER2-negative breast cancer

BACKGROUND The luminal subtype of breast cancer is sensitive to anti-estrogen therapy and shows a better prognosis than that of human epidermal growth factor receptor2 (HER2)-enriched or triple-negative breast cancer. However, the luminal type of breast cancer is heterogeneous and can have aggressive clinical features. We investigated the clinical implications of single hormone receptor negativity in a luminal B HER2-negative group. METHODS We collected luminal B HER2-negative breast cancer data that were estrogen receptor (ER) and/or progesterone receptor (PR) positive, Ki 67 high (>14 %), and HER2 negative and divided them into the ER- and PR-positive group and the ER- or PR-negative group. We analyzed the clinical and pathological data and survival according to ER or PR loss. RESULTS There were no statistical differences in TNM stage, breast and axillary operative methods, or number of tumors between the ER- and PR-positive group and ER- or PR-negative group. However, the ER- or PR-negative group was associated with older age (≥45 years), higher histological grade, lower Bcl-2 expression, and far higher Ki 67 (>50 %). Disease-free survival (DFS) and overall survival (OS) were shorter in the ER- or PR-negative group than that in the ER- and PR-positive group (p = 0.0038, p = 0.0071). CONCLUSIONS ER- or PR-negative subgroup showed worse prognosis than ER- and PR-positive subgroup in the luminal B HER2-negative group. We could consider the negativity of ER or PR as prognostic marker in luminal B HER2-negative subtype of breast cancer.