Alpha-fetoprotein is a major plasma protein in the fetus, where it is produced by the yolk sac and liver. In the adult its
concentration is very low except when a tumor such as hepatoma or teratoma is present. The similarity in physical
properties of AFP and albumin (103600) and the fact that their presence is inversely related suggested that AFP is the fetal
counterpart of serum albumin.
NCBI Summary:
This gene encodes alpha-fetoprotein, a major plasma protein produced by the yolk sac and the liver during fetal life. Alpha-fetoprotein expression in adults is often associated with hepatoma or teratoma. However, hereditary persistance of alpha-fetoprotein may also be found in individuals with no obvious pathology. The protein is thought to be the fetal counterpart of serum albumin, and the alpha-fetoprotein and albumin genes are present in tandem in the same transcriptional orientation on chromosome 4. Alpha-fetoprotein is found in monomeric as well as dimeric and trimeric forms, and binds copper, nickel, fatty acids and bilirubin. The level of alpha-fetoprotein in amniotic fluid is used to measure renal loss of protein to screen for spina bifida and anencephaly.
General function
Extracellular binding protein
Comment
Cellular localization
Secreted
Comment
Ovarian function
Germ cell development
Comment
Four cases of immature teratoma of the ovary are presented and the recent literature
is reviewed by Gallion H, et al . The majority of these tumors were confined to one ovary at the time of
diagnosis, and more than 75% occurred in women under 25 years of age. The two
most important prognostic parameters were stage of disease and histologic grade.
Optimal survival occurred when surgical tumor debulking was followed by
combination chemotherapy. The addition of hysterectomy with contralateral
adnexectomy did not improve the survival of patients with disease confined to one
ovary. Similarly, postoperative radiation therapy was not shown to be beneficial in
patients with this disease. Analysis of presently available data suggests that patients
with teratocarcinoma of the ovary should be treated with tumor excision followed by
at least 12 courses of chemotherapy with vincristine, actinomycin D, and
cyclophosphamide. alpha-Fetoprotein may be useful as a biochemical marker of
disease status in selected patients.
Expression regulated by
Comment
Ovarian localization
Primordial Germ Cell
Comment
Wu J, et al 2002 reported the expression of Fas, p53 and AFP in development of human fetal
germ cells in vitro.
A two-step culture system was used to study the
expression of Fas, p53 and alpha-fetoprotein (AFP) in the development in vitro
of human fetal germ cells. p53 mRNA was determined by Northern blotting, and
Fas content was assessed by western blotting. RT-nested polymerase chain
reaction (RT-nPCR) analysis was performed to determine the expression of AFP
mRNA in different stages of fetal follicular development. Follicular cell
apoptosis was evaluated by DNA fragmentation analyses (DNA ladder). The
results showed that by day 7 of culture approximately one-sixth of fetal germ
cells grew to class C oocytes (primary oocytes) from class B oocytes
(primordial oocytes) or class A oocytes. On day 45 of culture, one-third of
these primary follicles doubled in size. In the meantime, there was a high
proportion apoptosis of follicular cells on days 35 or 45 of culture, as
evident by a clear ladder pattern of DNA fragmentation upon electrophoretic
analysis. Expression of Fas antigen and p53 mRNA increased in a time-dependent
manner, while AFP mRNA was expressed on days 10 to 35, and disappeared on day
45. These results indicate that human fetal germ cells can develop in a
two-step culture system and AFP may play an active role in the proliferation
of these germ cells. At the late stage of follicular development in vitro a
number of follicular cells became apoptotic. Moreover, apoptosis may be the
mechanism responsible for fetal germ cell regression and the Fas antigen
and/or p53-mediate death pathway may be central in the induction of germ cell
regression.