AFP, or Alpha-fetoprotein, is a protein produced primarily by the liver and yolk sac of a developing fetus. In adults, it is typically found in low levels, but elevated levels can indicate certain medical conditions, including liver disease and some types of cancer, such as hepatocellular carcinoma. AFP testing is often used in prenatal screening to assess the risk of neural tube defects and other fetal abnormalities. Additionally, it can be a valuable tool in monitoring patients with liver conditions or those undergoing treatment for specific cancers, helping healthcare providers make informed decisions about patient care.