Biomarkers of disease are measurable indicators that can signal the presence or progression of a medical condition. These can include substances found in blood, other bodily fluids, or tissues that reflect the biological state of a disease. For example, elevated levels of cholesterol can indicate a risk for heart disease, while specific proteins may signal the presence of cancer. Biomarkers can be used for various purposes, including diagnosis, prognosis, and monitoring treatment response. They help healthcare professionals make informed decisions about patient care. Research continues to identify new biomarkers that could improve early detection and personalized treatment strategies for various diseases.