npj Breast Cancer
Genomic characterization of ER-positive primary tumors and corresponding relapses identifies potentially targetable alterations
Abstract The majority of breast cancer patients have tumors expressing estrogen receptor α (ER) and receive endocrine therapy. However, around one-third relapse in their disease, predominantly with retained ER expression. Molecular alterations are proposed to be contributors to the resistance mechanisms. Patients with ER-positive, human epidermal growth factor receptor 2 (HER2)-negative primary breast cancer with an ER-positive relapse