Leica甲型胎儿蛋白Alpha Fetoprotein Clone C3 7 mL BOND ready-to-use PA0963 P Antigen Background Alpha fetoprotein (AFP) is an oncofetal antigen of 70 kD found in body fluids which if detected in high concentrations has clinical implications. AFP is expressed in fetal liver but is not present under normal circumstances in healthy adult tissues. It is reported to be expressed in a proportion of germ cell tumors, with high frequency in yolk sac tumors. Human fetal liver: immunohistochemical staining for alpha fetoprotein using NCL-AFP. Note cytoplasmic staining of hepatocytes. Paraffin section.