# FGL1

Source: https://onco.cc/targets/fgl1/  
OnCo record `fgl1` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

FGL1 is a liver protein that some tumours secrete; it binds LAG-3 on T cells and switches them off, separately from the MHC class II route. It explains part of how LAG-3 blockade works.

## Summary

FGL1 (chromosome 8p22) is an immune-suppressive molecule that inhibits antigen-specific T-cell activation as a ligand of LAG-3, initiating signalling that inhibits the T-cell receptor in the immunological synapse; it binds LAG-3 independently of MHC class II, is liver-specific under normal conditions and is secreted by hepatocytes and certain tumour cells (UniProt Q08830, Q15116 context from P18627).

## Fields

- Kind: Target
- Last checked: 2026-09-24
- Also known as: fibrinogen like 1; HFREP-1; hepassocin
- Tags: checkpoint-map
- Symbol: FGL1
- Class: checkpoint
- Biology: A secreted fibrinogen-family protein; the second LAG-3 ligand after MHC class II.
- Where found: Liver (UniProt Q08830); Secreted by certain tumour cells (UniProt P18627)

## Notes

- Prevalence not recorded: HGNC and UniProt carry no positivity rates.

## Sources

- HGNC HGNC:3695: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:3695
- UniProt Q08830: https://www.uniprot.org/uniprotkb/Q08830/entry
- NCBI Gene 2267: https://www.ncbi.nlm.nih.gov/gene/2267

## Connected records

- targets: [HLA-DRA](https://onco.cc/targets/hla-dra/), [LAG-3](https://onco.cc/targets/lag3/)
- drugs: [Relatlimab + nivolumab](https://onco.cc/drugs/relatlimab-nivolumab/)
- technologies: [LAG-3 blockade](https://onco.cc/technologies/lag3-blockade/)
- pathways: [PD-1 / PD-L1 immune checkpoint & T-cell activation](https://onco.cc/pathways/pd1-checkpoint/)
- terms: [Checkpoint (two meanings)](https://onco.cc/terms/checkpoint/)

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JSON: https://onco.cc/api/v1/entities/fgl1.json