Publisher Summary α- Fetoprotein (AFP) is one of the most thoroughly characterized oncodevelopmental proteins. The salient features of the characteristics and expression of AFP are summarized in the chapter. The immunochemical properties and assay of AFP are also discussed. AFP was first detected by paper electrophoresis of fetal serum and it was detected, quantitated, and even purified using antibodies. AFP is strongly immunogenic when injected into a foreign species but does not elicit an immune response in the species of origin. With most globular proteins, the antigenicity of AFP seems to depend on the 3D conformation of the polypeptide chain. Human AFP unfolded by reduction in urea loses its inhibitory activity in the usual immunoassays. The concentration of AFP in fetal serum is in the range of milligrams per milliliter, and it usually gives rise to production of antibodies, even in an admixture with other fetal serum proteins. In most species, AFP is the only fetal serum protein present in appreciable quantities that is not shared by the adult serum. AFP has a well-established position as a diagnostic tool in the diagnosis and follow-up of liver cancer and germ cell tumors. It is also extremely useful in the early prenatal diagnosis of fetal anomalies, such as neural tube malformations and congenital nephrosis. As a well-characterized protein, AFP provides an important model system in the studies of the phenomena associated with gene expression.

alpha-Fetoprotein in cancer and fetal development.

Alpha fetoprotein (AFP) is the major protein of fetal serum and most resembles albumen, which replaces it shortly after birth. It is produced by fetal liver and passes into the amniotic fluid (AF) via fetal urine. A small amount crosses the membranes into the maternal circulation. Excluding fetal blood contamination, elevated AF/AFP levels indicate fetal demise or one of several abnormalities. Maternal serum (MS) AFP measurement can be used as a screening procedure to identify neural tube defects providing a rigorous protocol is followed. This requires that a laboratory establish its normal range of MS/AFP levels between 15 and 20 weeks gestation, employ a reliable assay with adequate controls, and has recourse to genetic counseling as well as expert sonography, amniocentesis and amniography if necessary. Pregnancy is the only normal situation in which AFP is present after birth. It may be present in high levels in certain malignancies and has been useful in monitoring their recurrence. This article will review the history, biochemistry, and different assays of AFP in AF and blood as well as the indications and limitations for their use.

Alpha-fetoprotein: a review.

Alpha-Fetoprotein Levels in Normal Adults

Alpha-fetoprotein (AFP) was 1 of the first serum protein markers to serve in the dual capacities of tumor marker and fetal defect marker, ie, an oncofetal protein, in the clinical laboratory. Although the serum-marker capacity of AFP has long been used, less is known of the fluid compartments of this oncofetal protein during fetal and perinatal development. In this review, the biologic activities of AFP are discussed in light of its presence in the various biologic fluid compartments: fetal serum, amniotic fluid, cord blood, urine, and maternal serum. AFP concentrations within the biologic fluids are considered in the context of gestational age, sex, body weight, and anatomic location. Discussion follows concerning the relationships and roles of AFP in various developmental disorders such as hypothyroidism, folate deficiencies, autoimmune disorders, acquired immunodeficiency disorder (AIDS), congenital heart defects, cystic fibrosis, preeclampsia/hypertension, and platelet aggregation disorders. Based on its presence in so many types of birth defects, malformations, and congenital anomalies, AFP can be seen to serve as a form of molecular "duct tape" during pregnancy and postnatal development.

Levels of alpha-fetoprotein during pregnancy and early infancy in normal and disease states

https://jdc.jefferson.edu/cgi/viewcontent.cgi?article=1011&context=gastro_hepfp

Relative telomere length: a novel non-invasive biomarker for the risk of non-cirrhotic hepatocellular carcinoma in patients with chronic hepatitis B infection.

Alpha-Fetoprotein (AFP) levels of 1,335 males (15 years and older) of seven ethnic groups (Chinese, Indians, and Malays from Singapore, Caucasians from Lyon, and Blacks from Nairobi, forest, and the savanna region of the Ivory Coast) were determined by radioimmunoassay. A few elevated levels (up to 30 nanounits/ml) were detected in some normal individuals, especially in the older age-groups. In addition, there was a systematic age-dependency of AFP levels particularly evident in the groups from Singapore-Lyon, in which there was a 50% AFP increase between the ages of 20 and 40. Comparison between Africans on the one hand and people from Singapore-Lyon on the other hand revealed highly significant differences (p less than 0.001), especially in the younger groups, whereas Chinese, Malays, and Indians from Singapore had very similar AFP pattern; this suggests an important role for environmental factors in the regulation of AFP levels. The age dependency of the presumed effect of environmental factors is in keeping with experimental data showing that young animals respond more vigorously to AFP-stimulating factors. Although the incidence of hepatocellular carcinoma (HCC) differs in the three Singapore groups (the highest in Chinese and the lowest in Indians), no relationship was observed in this study between mean AFP level and HCC incidence in Singapore.

P. Sizaret

Papers

Alpha-Fetoprotein levels in normal males from seven ethnic groups with different hepatocellular carcinoma risks.