A predictive biomarker is a biological indicator that helps predict how a patient will respond to a specific treatment. These markers can be found in blood, tissue, or other bodily fluids and are often used in personalized medicine to tailor therapies to individual patients. For example, certain genetic mutations in cancer cells can indicate whether a patient will benefit from targeted therapies. By identifying predictive biomarkers, healthcare providers can make more informed decisions about treatment options, potentially improving outcomes and reducing unnecessary side effects. This approach is particularly important in fields like oncology, where treatments can vary significantly based on a patient's unique biological makeup.