AFP (Alpha Fetoprotein)
The DRG AFP ELISA is an enzyme immunoassay for measurement of alpha fetoprotein (AFP) in serum. In the United States
Alpha-fetoprotein (AFP) is a glycoprotein with a molecular weight of approximately 70 KD(1). AFP is normally produced during fetal and neonatal development by the liver, yolk sac, and in small concentrations by the gastrointestinal tract (2). After birth, serum AFP concentrations decrease rapidly, and by the second year of life and thereafter only trace amounts are normally detected in serum (3).
Elevation of serum AFP to abnormally high values occurs in several malignant diseases (4-7), most notably nonseminomatous testicular cancer and primary hepatocelluar carcinoma. In the case of nonseminomatous testicular cancer, a direct relationship has been observed between the incidence of elevated AFP levels and the stage of disease (8- 9). Elevated AFP levels have also been observed in patients diagnosed with seminoma with nonseminomatous elements, but not in patients with pure seminoma (6,8,10-11).
In addition, elevated serum AFP concentrations have been measured in patients with other noncancerous diseases, including ataxia telangiectasia, hereditary tyrosinemia, neonatal hyperbilirubinemia, acute viral hepatitis, chronic active hepatitis and cirrhosis (12-15). Elevated serum AFP concentrations are also observed in pregnant women (16-17).
Therefore, AFP measurements are not recommended for use as a screening procedure to detect the presence of cancer in the general population.
The DRG AFP ELISA Kit is a solid phase enzyme-linked immunosorbent assay (ELISA) based on the sandwich principle.
The microtiter wells are coated with a monoclonal [mouse] antibody directed towards a unique antigenic site on an AFP molecule. An aliquot of sample containing endogenous AFP is incubated in the coated well with enzyme conjugate, which is an anti-AFP antibody conjugated with horseradish peroxidase. After incubation the unbound conjugate is washed off.
The amount of bound peroxidase is proportional to the concentration of AFP in the sample.
Having added the substrate solution, the intensity of colour developed is proportional to the concentration of AFP in the sample.
- Ruoslahti, E. and Seppala, M., Studies of Carcino-Fetal Proteins: Physical and Chemical Properties of Human Alpha- Fetoprotein. Int. J. Cancer 7:218, 1971.
- Gitlin, D., Perricelli, A. and Gitlin, G. M., Synthesis of Alpha-Fetoprotein by Liver, Yolk Sac, and Gastrointestinal Tract of the Human Conceptus. Cancer Res. 32:979, 1972.
- Masseyeff, R., Gilli, G., Krebs, B., Bonet, C. and Zrihen, H., Evolution en Fonction de I’Age du Taux Serique Physiologique de I’Alpha-Foetoproteine chez I’Homme et le Rat. (French) in Alpha-Feto-Protein (Masseyeff, R., ed.) p.313. INSERM, Paris, 1974.
- Silver, H. K. B., Gold, P., Feder, S., Freedman, So. O. and Shuster, J., Radioimmunoassay for human alphafetoprotein. Proc. Nat. Acad. Sci. U.S.A. 70:526, 1973.
- Waldmann, T. A. and McIntire, K. R., The use of a radioimmunoassay for alpha-fetoprotein in the diagnosis of malignancy. Cancer 34:1510, 1974.
- Kohn, J., Orr, A.H. McElwain, T.J., Bentall, M. and Peckham, M. J., Serum alpha-fetoprotein in patients with testicular tumors. Lancet 2:433, 1976.
- Abelev, G.I., Alpha-fetoprotein in ontogenesis and its association with malignant tumors. Adv. Cancer Res. 14: 295, 1971.
- Scardino, P. T., Cox, H. D., Waldermann, T. A., McIntire, K. R., Mittemeyer, B. and Javadpour, N., The value of the serum tumor markers in the staging and prognosis of germ cell tumors of the testis. J. Urol. 118:994, 1977.
- Bosl, G.J., Lange, P. H., Fraley, E. E., Goldman, A., Nochomovitz, L. E., Rosai, J., et al., Human chorionic gonadotropin and alpha-fetoprotein in the staging of nonseminomatous testicular cancer. Cancer 47:328, 1981
- Lange, P.H., McIntire, K.R. and Waldmann, T. A., Hakala, T.R. and Fraley, E. E., Serum alpha-fetoprotein and human chorionic gonadotropin in the diagnosis and management of nonseminomatous germ-cell testicular cancer. Medical Intelligence 259:1237, 1976.