Background: Breast cancer is the primary cause of cancer-associated mortality among women worldwide. There have been many studies related to biomarkers in breast cancer.

Content: A Biomarker is a molecule in the body that is present in blood, other bodily fluids, or tissue and serves as an indicator of an aberrant or normal process, a condition, or an illness like cancer. Biomarkers in breast cancer that have been widely used in clinical settings include estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER2), Ki67, CEA, and Ca15-3. Circulating tumor cell (CTC) and genome sequencing are currently being researched and expected to be useful in the management of breast cancer patients.

Summary: Biomarkers are crucial for diagnosing, classifying, and determining the most effective treatment strategies such as personalized and targeted therapies for individuals with breast cancer. It also can be used as a prognostic tool to predict response toward therapeutic intervention and to detect disease recurrence. Technologies of breast cancer biomarkers are evolved and expected will produce a better patient outcome.