Clinical relevance was examined by analyzing patient datasets and tumor tissue microarrays.<h4>Results</h4>FOXA2 expression was significantly elevated in tamoxifen-resistant (TamR) and ERα-negative breast cancer cells compared to that in ERα-positive MCF-7 cells, regardless of tamoxifen treatment or ERα depletion. The gene discussed is FOXA2; the disease is breast carcinoma.