Biomarkers are measurable indicators that can help identify the presence or progression of a disease. They can be found in blood, other bodily fluids, or tissues and are often used in medical research and clinical practice. For example, a specific protein level in the blood might indicate the presence of a condition like diabetes or cancer. These markers can also help doctors monitor how well a treatment is working. By tracking changes in biomarkers over time, healthcare professionals can make more informed decisions about a patient's care. This makes biomarkers essential tools in personalized medicine, where treatments are tailored to individual patients based on their unique biological characteristics.