To further examine the correlation between H2ac and ER expression in human ER+ breast cancer, we performed immunohistochemistry (IHC) on a tissue microarray panel (TMA) that included 122 breast cancer cases (34 ER+ breast carcinoma, 82 ER− breast carcinoma and 6 ER− cancer-adjacent normal breast tissues]. The gene discussed is ESR1; the disease is cancer.