# FAP

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

## TL;DR

FAP (fibroblast activation protein) sits on the cancer-associated fibroblasts that scaffold more than 90% of epithelial cancers and is almost absent from normal adult tissue. FAPI PET tracers therefore light up tumours with high contrast, including pancreatic, gastric and low-grade cancers where FDG PET is weak, and FAP-targeted radioligands are in development.

## Summary

Fibroblast activation protein is expressed on cancer-associated fibroblasts in >90% of epithelial cancers, with minimal expression in normal adult tissue. FAPI PET tracers (68Ga-FAPI-46, 18F-FAPI-74) offer high tumour-to-background contrast, including in cancers where FDG is weak (pancreatic, gastric, low-grade). FAP-targeted radioligands (177Lu/225Ac-FAP-2286) are in development.

## Fields

- Kind: Target
- Last checked: 2026-09-04
- Tags: theranostic; pet-target; stroma
- Symbol: FAP
- Class: stroma
- Biology: Serine protease on activated fibroblasts; a stromal target rather than a tumour-cell target, so it is pan-cancer but does not report on the malignant cell itself.
- Where found: Pancreatic; Gastric; Breast; Sarcoma; Almost all desmoplastic tumours

## Notes

- Pancreatic ductal adenocarcinoma: FAP-positive cancer-associated fibroblasts are the principal source of CXCL12, which coats cancer cells and excludes T cells; depleting them or blocking CXCR4 let T cells in and uncovered the effect of anti-PD-L1 in the autochthonous mouse model (Feig 2013). FAP is also the imaging target of FAPI PET in this stroma-rich disease.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Fibroblast_activation_protein,_alpha
- Wikipedia: https://en.wikipedia.org/wiki/Fibroblast_activation_protein,_alpha

## Connected records

- cancers: [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/), [Hepatocellular carcinoma](https://onco.cc/cancers/hcc/), [Locally advanced unresectable pancreatic ductal adenocarcinoma](https://onco.cc/cancers/locally-advanced-pdac/), [Metastatic pancreatic ductal adenocarcinoma](https://onco.cc/cancers/metastatic-pdac/), [Pancreatic ductal adenocarcinoma](https://onco.cc/cancers/pancreatic/), [Sarcomas (soft tissue, bone, GIST)](https://onco.cc/cancers/sarcoma/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- drugs: [EB-MF-CAR-NK-01](https://onco.cc/drugs/eb-mf-car-nk-01/), [FAP-2286 (177Lu / 68Ga)](https://onco.cc/drugs/fap-2286/)
- companies: [Ratio Therapeutics](https://onco.cc/companies/ratio-therapeutics/), [SOFIE Biosciences](https://onco.cc/companies/sofie-biosciences/)
- terms: [Cancer-associated fibroblasts (CAFs)](https://onco.cc/terms/cancer-associated-fibroblasts/), [Desmoplasia (tumour stroma)](https://onco.cc/terms/desmoplasia/), [Immune exclusion](https://onco.cc/terms/immune-exclusion/), [Mechanical theory: stiffness, pressure and force as causes](https://onco.cc/terms/mechanical-theory-of-cancer/), [Microenvironment and inflammation: tumours as wounds that do not heal](https://onco.cc/terms/microenvironment-inflammation-theory/)
- key papers: [Depletion of carcinoma-associated fibroblasts and fibrosis induces immunosuppression and accelerates pancreas cancer with reduced survival](https://onco.cc/key-papers/paper-ozdemir-caf-depletion-accelerates-pancreatic-cancer-cancer-cell-2014/), [Distinct populations of inflammatory fibroblasts and myofibroblasts in pancreatic cancer](https://onco.cc/key-papers/paper-ohlund-caf-subtypes-mycaf-icaf-jem-2017/), [Targeting CXCL12 from FAP-expressing carcinoma-associated fibroblasts synergizes with anti-PD-L1 immunotherapy in pancreatic cancer](https://onco.cc/key-papers/paper-feig-cxcl12-fap-cafs-t-cell-exclusion-pnas-2013/)
- roadmaps: [Cell therapy roadmap: CD19 CAR-T → solid tumours → in vivo CAR](https://onco.cc/roadmaps/cell-therapy-roadmap/), [Pancreatic cancer roadmap: from Whipple's operation to gemcitabine, FOLFIRINOX, adjuvant chemotherapy, PARP inhibition, KRAS inhibition, vaccines and the surveillance question](https://onco.cc/roadmaps/pancreatic-roadmap/)
- ideas: [Anchor a TGF-beta trap in the tumour stroma so it cannot act everywhere](https://onco.cc/ideas/idea-bio2-tumour-anchored-tgfbeta-trap/), [Block the survival signals the tumour's neighbours provide](https://onco.cc/ideas/idea-bio1-stromal-resistance-blockade/), [FAP theranostics as a pan-cancer stromal strategy](https://onco.cc/ideas/idea-fap-theranostics-pancancer/), [FAPI PET as the workup for MCED positives](https://onco.cc/ideas/idea-mced-plus-fapi/), [Make every cold tumour hot: a coordinated programme to reprogramme immune-excluded tumours](https://onco.cc/ideas/idea-moon-cold-to-hot-programme/), [Match therapy to the type of scar-forming cell in the tumour](https://onco.cc/ideas/idea-bio2-caf-subtype-assignment/), [Reprogramme the stroma rather than remove it: second-generation stromal trials with a stromal biomarker and a survival endpoint](https://onco.cc/ideas/idea-pdac-stromal-reprogramming-not-depletion/), [What actually holds T cells at the tumour border?](https://onco.cc/ideas/idea-immune-exclusion-drivers/)
- technologies: [CAR-T against stroma: fibroblasts and myeloid cells](https://onco.cc/technologies/stroma-directed-car/), [FAPI PET](https://onco.cc/technologies/fapi-pet/), [Radioligand therapy (beta emitters)](https://onco.cc/technologies/radioligand-therapy/), [Targeted alpha therapy](https://onco.cc/technologies/targeted-alpha-therapy/), [Targeting tumour mechanics and pressure](https://onco.cc/technologies/mechanobiology-therapy/)
- institutions: [Heidelberg University Hospital / NCT / DKFZ](https://onco.cc/institutions/heidelberg-nct/), [University Hospital Düsseldorf / CIO Düsseldorf](https://onco.cc/institutions/uk-duesseldorf/)
- people: [Erik Sahai](https://onco.cc/people/erik-sahai/), [Frederik Giesel](https://onco.cc/people/frederik-giesel/), [Ken Herrmann](https://onco.cc/people/ken-herrmann/), [Shaoli Song](https://onco.cc/people/song-shaoli/), [Uwe Haberkorn](https://onco.cc/people/uwe-haberkorn/)
- bottlenecks: [Cold tumours and the immunosuppressive microenvironment](https://onco.cc/bottlenecks/b-tme-immunosuppression/)
- pathways: [Cold tumours: immune deserts and exclusion](https://onco.cc/pathways/immune-desert-exclusion/), [Fibroblast activation, desmoplasia & matrix stiffness](https://onco.cc/pathways/caf-activation-desmoplasia/), [Invasion: proteases, adhesion & the invasive front](https://onco.cc/pathways/invasion-ecm-degradation/), [Tumour microenvironment (TME)](https://onco.cc/pathways/tumor-microenvironment/)

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