Abstract
The advent of precision medicine targeting oncogenic mutations and other alterations has led to a paradigm shift in the treatment of many solid tumors and hematologic malignancies. For many of these agents, predictive biomarker testing is necessary to determine the presence of such alterations in order to select patients who are most likely to respond, and to avoid the use of ineffective and potentially harmful alternative therapy. Recent technological advances such as next-generation sequencing have facilitated the identification of targetable biomarkers in patients with cancer and thus help inform treatment decisions. Moreover, new molecular-guided therapies and associated predictive biomarkers continue to be discovered. For some cancer therapeutics, regulatory approval requires the use of a companion diagnostic to ensure proper patient selection. Advanced practitioners therefore need to be aware of current biomarker testing guidelines regarding who should be tested, how and when to test, and how these results can guide treatment decisions using molecular-based therapies. They should also recognize and address potential barriers and disparities in biomarker testing to ensure equitable care for all patients, and assist in educating patients and colleagues alike on the importance of testing and integration into clinical practice to enhance outcomes.