In the present study, we examined the expression of FOXO3a by immunohistochemical analysis in breast carcinoma specimens of 70 patients and compared FOXO3a expression with various established disease markers, such as tumor size, histologic grade, axillary lymph node status, ER status, PR status, HER-2 status, TNM stage and histology, and then performed survival analyses, including standard prognostic variables, in female patients with breast cancer. This evidence concerns the gene ESR1 and breast carcinoma.