AFP (Alpha-Fetoprotein) Gene
Key biomarker in hepatocellular carcinoma and germ cell tumors
Gene Information Card
| Symbol | AFP |
|---|---|
| Full Name | Alpha-fetoprotein |
| Gene Type | protein-coding |
| Chromosomal Location | 4q13.3 |
| NCBI Gene ID | 174 ncbi.nlm.nih.gov/gene/174 |
| Ensembl ID | ENSG00000081051 |
| UniProt ID | P02771 |
| OMIM ID | 104150 |
| HGNC ID | 317 |
| Aliases | AFPD, FETA, HPAFP |
Description
AFP (alpha-fetoprotein) is a gene located on chromosome 4q13.3 that encodes a major plasma protein produced primarily by the fetal liver and yolk sac. In adults, AFP expression is normally repressed but is frequently reactivated in hepatocellular carcinoma and germ cell tumors, making it a widely used serum biomarker for these malignancies. The protein functions as a carrier and regulator of growth factors, and its expression is regulated by transcription factors including HNF1 and C/EBP.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Hepatocellular carcinoma | Reactivation of AFP expression in malignant hepatocytes; used as diagnostic and prognostic serum marker | ClinVar, COSMIC, NCBI |
| Germ cell tumors (e.g., yolk sac tumor) | Elevated AFP due to tumor production; key component of tumor marker panels | ClinVar, OMIM |
| Hereditary persistence of alpha-fetoprotein (HPAFP) | Benign elevation of AFP due to promoter or regulatory region variants | OMIM 104150, ClinVar |
| Ataxia telangiectasia | Elevated AFP as a diagnostic biomarker; not directly caused by AFP mutations but used in screening | OMIM, NCBI |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver (fetal) | High | Very high |
| Liver (adult) | 0.1 | Low |
| Yolk sac | High | Very high |
| Testis (germ cell tumors) | Variable | High in certain subtypes |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | High | Hepatocellular carcinoma cell line |
| Huh7 | High | Hepatocellular carcinoma cell line |
| HEK293 | Low | Embryonic kidney; minimal AFP expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | missense | Rare | Likely loss of function; associated with HPAFP |
| c.559G>A (p.Gly187Arg) | missense | Rare | Uncertain significance; reported in ClinVar |
| c.1072C>T (p.Arg358*) | nonsense | Rare | Premature stop; likely loss of function |
Mutation functional classification
Loss of Function (LOF)
Nonsense and frameshift variants leading to truncated protein; associated with reduced AFP levels in HPAFP.
Gain of Function (GOF)
Not well documented; AFP overexpression in tumors is typically due to transcriptional reactivation rather than gain-of-function mutations.
Dominant Negative (DN)
No known dominant-negative mutations reported for AFP.
View complete mutation data：
Gene Ontology (GO)
| • GO:0005576 - extracellular region | • GO:0008285 - negative regulation of cell proliferation |
| • GO:0008284 - positive regulation of cell population proliferation | • GO:0033572 - transferrin transport |
| • GO:0042493 - response to drug |
Pathways
• Regulation of IGF transport and uptake by insulin-like growth factor binding proteins (Reactome: R-HSA-381340)
• Post-translational modification: synthesis of GPI-anchored proteins (Reactome: R-HSA-163125)
Protein Summary
Alpha-fetoprotein (AFP) is a 69 kDa glycoprotein belonging to the albuminoid family. It is composed of three domains and binds various ligands including bilirubin, fatty acids, and metals. AFP is synthesized during fetal development and is the major serum protein in the fetus. In adults, AFP levels are very low but can rise dramatically in hepatocellular carcinoma and germ cell tumors, serving as a critical tumor marker. The protein also has immunomodulatory and growth-regulating properties.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| AFP Knockout HEK293 Cell Line | EDJ-KQ1400 | Human | 174 | Details Get a Quote |
| AFP Knockout A-549 Cell Line | EDJ-KQ20931 | Human | 174 | Details Get a Quote |
| AFP Knockout HeLa Cell Line | EDJ-KQ20932 | Human | 174 | Details Get a Quote |
| AFP Knockout HCT 116 Cell Line | EDJ-KQ69536 | Human | 174 | Details Get a Quote |
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