Go online to PeerView.com/FGB860 to view the activity, download slides and practice aids, and complete the post-test to earn credit. HER2-targeting therapies have led to remarkable improvements in patients with HER2-positive early and advanced breast cancer. Recently, novel antibody–drug conjugates (ADCs) and other HER2-targeting therapies have also demonstrated impressive activity in patients with HER2-low breast cancer, who account for approximately 40%-50% of patients with breast cancer and are a population with a high unmet medical need. The concepts of how to best define and test for HER2-low breast cancer are evolving, but the modern HER2-targeting agents offer new hope for dramatically improved outcomes in patients who currently have limited options. This PeerView educational video, based on a recent live symposium, explores the biology and foundational concepts of HER2-low breast cancer, highlights the rationale for and data supporting the use of HER2-targeted therapies in HER2-low breast cancer, assesses emerging approaches for identifying patients with HER2-low breast cancer who could benefit from HER2-targeted therapies, and clarifies how to best incorporate these therapies into practice in real-world settings. Clinical case scenarios are also used to provide useful guidance for testing and treatment of patients with HER2-low breast cancer. Upon completion of this activity, participants should be better able to: Explain the biologic rationale and clinical evidence on the growing role of HER2-targeting therapies in the treatment of patients with HER2-low breast cancer; Apply standard and emerging testing approaches to identify patients with HER2-low breast cancer to determine their eligibility for novel HER2-targeted therapies; Integrate individualized management plans that incorporate a collaborative and coordinated multidisciplinary team-based approach to care in accordance with the latest treatment guidelines and recommendations for patients with lower spectrum HER2-expressing breast cancer in the context of clinical practice or clinical trials