Gene Signature: A Guideline for Hormonal Therapy in Breast Cancer

Breast cancer is the most common leading cause of cancer-related death in women world wide and it is a molecular heterogeneous disease. The heterogeneous expression of hormone receptors such as estrogen receptor (ER), progesterone receptor (PR), and HER2, has been used to divide breast cancer patients into intrinsic subtypes based on the present or absence of these hormone receptors. And it also helps guide judicious treatment decisions in response to either hormonal therrapy, chemotherapy, or radiation therapy. Hormonal therapies such as tamoxifen, aromatase inhibitors or any therapies that target HER2 receptors line like Herceptin, are helpful in hormone receptor-positive breast cancers, but not in patients whose tumors are hormone receptor negative. However, identification of patients who might benefit from these treatments and who are at high risk of reoccurrence and resistance after treatment need to improve.