ABSTRACT
Currently, breast cancer is a common malignancy in female, and previous guidelines recommended that one of the key biomarkers for breast cancer, human epidermal growth factor receptor 2 (HER2), is classified as either positive or negative to guide clinicians’ treatment decisions. While nearly half of breast cancer patients have low HER2 expression (IHC expression is 1+ or 2+ and ISH detection is negative), such patients are insensitive to traditional anti-HER2 targeted therapy. However, novel antibody-drug conjugates (ADCs) provide new targeted therapy options for breast cancer patients with low HER2 expression, challenging the traditional binary concept and arousing research enthusiasm. In the latest ASCO/CAP guidelines for HER2 detection in breast cancer, HER2-low breast cancer has been included as a clinical treatment subgroup. This article will review the definition of HER2-low breast cancer, the progress of drug therapy such as ADC, and the current challenges faced by this subgroup.
ABSTRACT
The latest statistics show that breast cancer (BC) has become the cancer with the highest incidence in the world, seriously affecting women′s physical and mental health, and has become a hot research topic in the medical field. Accordingly, its treatment has also entered the molecular era. According to its molecular classification, BC is mainly divided into Luminal A, Luminal B, simple human epidermal growth factor receptor 2 (HER2)-positive and triple negetive breast cancer (TNBC). Obviously, correct judgment of HER2 expression status is very important for cancer typing and treatment of breast cancer. With the further development of research, some scholars have recently put forward new viewpoints and views on the interpretation of HER2 expression and cancer typing in breast cancer. This review will introduce the HER2-low breast cancer combined with the current frontier viewpoint and research findings, hoping to provide a reference for the precision treatment of breast cancer in the later stage and related further research.