Nuclear Receptors in Breast Cancer

Breast cancer (BC) is classified into four major molecular subtypes. The most predominant subtypes, luminal A and B are hormone receptor-positive BC (ERα +/PR+) which accounts for over 70% of BC cases. ERα +/PR+ breast cancers are treated with selective estrogen-receptor modulators such as tamoxifen, directed against the main therapeutic target estrogen receptor α (ERα). Tumors with HER2+ amplification are targeted by monoclonal antibody trastuzumab which significantly contributes to better prognosis. Finally, Triple-negative breast cancer has no therapeutic target identified, leaving patients with chemotherapy as their main option. Despite the overall success of chemotherapy, endocrine therapy, and the use of monoclonal antibody, one of the major challenges of BC is cancer recurrence. ERα is a member of the super family of nuclear receptors (NRs), which are ligand-dependent transcription factors that are involved in many biological processes associated with cancer. Based on ERα biological importance and utility in the management of BC, we hypothesized that NRs other than ERα might serve as potential markers and offer new therapeutic approaches for BC patients.