Poor-prognosis estrogen receptor- positive disease: present and future clinical solutions.

Use of chemotherapy for patients with estrogen receptor (ER)-positive breast cancer has been a conflicting issue. Recent studies have identified predictive markers allowing identification of poor-prognosis ER-positive breast cancers in need of more aggressive therapy. In general, tumours belonging to the so-called luminal B class, tumours expressing a high Ki67, human epidermal growth factor receptor 2 (HER-2) overexpression or a high score on the Oncotype DX gene expression profile reveal a poor prognosis compared with ER-rich tumours of the luminal A class. In contrast, recent studies have shown these tumours, contrasting tumours of the luminal A class, to benefit from more aggressive anthracycline-containing chemotherapy including a taxane. In the case of metastatic disease, patients with HER-2-positive, ER-positive tumours may benefit from having endocrine therapy and an anti-HER-2 agent administered in combination.