Entinostat and Anastrozole in Treating Postmenopausal Women With TNBC That Can Be Removed by Surgery

PRIMARY OBJECTIVES: I. To evaluate the safety and tolerability of entinostat in combination with anastrozole or tamoxifen. (Pilot) II. To determine the optimal dose of entinostat in combination with anastrozole or tamoxifen for phase II. (Pilot) III. To determine baseline and percentage change in proliferative index (Ki67) before and after treatment with entinostat and anastrozole/tamoxifen in triple negative breast cancer (TNBC). (Phase II) IV. To determine the estrogen receptor (ER) expression after treatment with entinostat and anastrozole/tamoxifen in TNBC. (Phase II) SECONDARY OBJECTIVES: I. To evaluate baseline and change in the expression levels of progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR), cytokeratin 5/6 (CK5/6), and aromatase before and after treatment with entinostat and anastrozole/tamoxifen. II. To assess baseline and change in tumor tissue histone H3 and H4 acetylation before and after treatment with entinostat and anastrozole/tamoxifen. III. To assess the clinical and pathological response to preoperative combination of entinostat and anastrozole/tamoxifen in TNBC. TERTIARY OBJECTIVES: I. To correlate the levels of histone H3 and H4 acetylation in tumors with the changes in Ki67 and ER. II. To evaluate baseline and change in gene methylation silencing and expression of candidate genes in tissues and in circulating DNA, including estrogen receptor (ER)-alpha, ER-beta, RAR-beta, cyclin D2, Twist, RASSF1A, and HIN-1. III. To correlate entinostat trough concentrations with histone H3 and H4 acetylation in tumors as well as the change in Ki67 and ER. IV. To evaluate baseline and change in the global gene expression profile before and after treatment with entinostat and anastrozole/tamoxifen. OUTLINE: This is a multicenter, pilot study followed by a phase II study. Patients receive entinostat orally (PO) once daily on days 1, 8, 15, 22, and 29 and anastrozole PO once daily on days 4-29. Patients then undergo mastectomy or lumpectomy. Tumor tissue samples are collected at baseline or from original diagnosis, and during surgery for correlative studies by IHC and RT-PCR. Blood samples are also collected at baseline, on days 1 and 15, and during surgery for correlative studies. After completion of study therapy, patients are followed up for 30 days.