[Targeted Therapy in Metastatic Breast Cancer-Which Molecular Tests Are Necessary?]

In recent years, targeted therapy for breast cancer has received increasingly more attention. In addition to hormone receptors and human epidermal growth factor 2 (HER2), the immunohistochemical detection of programmed cell death ligand 1 (PD-L1) in advanced triple-negative breast cancer and the detection of mutations in the breast cancer 1 (BRCA1) or BRCA2 gene in the patient's germline and mutations in the phosphatidylinositol 3 kinase (PI3K) pathway are currently relevant when making decisions regarding targeted therapy.