# CD137 (4-1BB, TNFRSF9)

Source: https://onco.cc/targets/cd137/  
OnCo record `cd137` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

4-1BB is a switch on activated T cells that makes them live longer and kill better. Rather than press it everywhere, new bispecific antibodies press it only on T cells that are already touching a tumour cell marked by PD-L1 or HER2.

## Summary

TNFRSF9 (chromosome 1p36.23) encodes CD137 (4-1BB), the receptor for 4-1BB ligand (TNFSF9); its signal enhances CD8 T-cell survival, cytotoxicity and mitochondrial activity and so promotes immunity against viruses and tumours (UniProt Q07011). In OnCo it is the costimulatory arm of two tumour-anchored bispecifics: acasunlimab (PD-L1 x 4-1BB) in phase 3 for NSCLC, and cinrebafusp alfa (PRS-343), a HER2/4-1BB anticalin-antibody fusion protein that binds HER2 on tumour cells while engaging 4-1BB to costimulate T cells, in HER2-positive gastric cancer.

## Fields

- Kind: Target
- Last checked: 2026-09-22
- Also known as: 4-1BB; CD137; ILA; TNF receptor superfamily member 9
- Tags: wave5-target
- Symbol: TNFRSF9
- Class: surface-antigen
- Biology: Both corpus agents cluster 4-1BB only where the other arm has bound a tumour antigen (PD-L1 or HER2), so costimulation is confined to T cells in contact with the tumour rather than delivered systemically.
- Where found: Activated CD8 T cells; NSCLC (acasunlimab) and HER2-positive gastric cancer (cinrebafusp alfa) trials

## Notes

- Prevalence not recorded in this wave: HGNC and UniProt carry no positivity rates and no other source was consulted.

## Sources

- HGNC HGNC:11924: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:11924
- UniProt Q07011: https://www.uniprot.org/uniprotkb/Q07011/entry
- NCBI Gene 3604: https://www.ncbi.nlm.nih.gov/gene/3604

## Connected records

- targets: [CD28](https://onco.cc/targets/cd28/), [HER2](https://onco.cc/targets/her2/), [PD-L1](https://onco.cc/targets/pdl1/)
- cancers: [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/), [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/)
- technologies: [Bispecific antibodies](https://onco.cc/technologies/bispecific-antibody/)
- drugs: [Acasunlimab](https://onco.cc/drugs/acasunlimab/), [Cinrebafusp alfa](https://onco.cc/drugs/cinrebafusp-alfa/)
- pathways: [PD-1 / PD-L1 immune checkpoint & T-cell activation](https://onco.cc/pathways/pd1-checkpoint/), [The cancer-immunity cycle](https://onco.cc/pathways/cancer-immunity-cycle/)

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JSON: https://onco.cc/api/v1/entities/cd137.json