Evidence map›Paper›PMID 41761350›Full record

ArticleCancer imaging : the official publication of the International Cancer Imaging Society2026

Preclinical evaluation of FAP-targeted PET imaging to investigate CAF responses to radiotherapy.

Kristin Lode, Sindhu Kancherla, Yngve Guttormsen, Rodrigo Berzaghi, Vera Susana Maia, Angel Moldes-Anaya, Turid Hellevik, Mathias Kranz, Inigo Martinez-Zubiaurre

Abstract read
In one paragraph

Article in Cancer imaging : the official publication of the International Cancer Imaging Society, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

9 authors.

Kristin LodeDepartment of Clinical Medicine, Molecular Inflammation & Irradiation Research Group, UiT the Arctic University of Norway, Tromsø, Norway.
Sindhu KancherlaDepartment of Clinical Medicine, Molecular Inflammation & Irradiation Research Group, UiT the Arctic University of Norway, Tromsø, Norway.
Yngve GuttormsenDepartment of Clinical Medicine, Nuclear Medicine and Radiation Biology Research Group, UiT the Arctic University of Norway, Tromsø, Norway.
Rodrigo BerzaghiDepartment of Clinical Medicine, Molecular Inflammation & Irradiation Research Group, UiT the Arctic University of Norway, Tromsø, Norway.
Vera Susana MaiaDepartment of Clinical Medicine, Molecular Inflammation & Irradiation Research Group, UiT the Arctic University of Norway, Tromsø, Norway.
Angel Moldes-AnayaPET Imaging Center, University Hospital of Northern Norway, Tromsø, Norway.
Turid HellevikDepartment of Radiation Oncology, University Hospital of Northern Norway, Tromsø, Norway.
Mathias Kranz *PET Imaging Center, University Hospital of Northern Norway, Tromsø, Norway.
Inigo Martinez-Zubiaurre *Department of Clinical Medicine, Molecular Inflammation & Irradiation Research Group, UiT the Arctic University of Norway, Tromsø, Norway. inigo.martinez@uit.no.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundCancer-associated fibroblasts (CAFs) are influential elements of the tumor microenvironment with significant roles in tumor progression and therapy resistance. However, the effects that radiotherapy has on CAFs dynamics remain understudied. This study aimed to provide a non-invasive PET imaging approach to quantify radiation-induced changes in cancer-associated fibroblasts in preclinical tumor models.

methodsThe FAP-specific radiotracer [18F]AlF-FAPI-74 was used to monitor CAFs dynamics following precision external beam radiotherapy (RT) in two syngeneic subcutaneous murine tumor models (LLC and CT26). Tumors were irradiated via two radiation regimens (1 × 12 Gy or 2 × 6 Gy), and dynamic PET/MR imaging was performed 7 days after RT. Additionally, the dynamics of FAP+ CAFs in tumors were quantified ex vivo via flow cytometry and immunohistochemistry.

resultsTumor-targeted irradiation led to a significant reduction in tumor size. Uptake of [18F]AlF-FAPI-74 in subcutaneous tumors was low but significantly above muscle-background values. Quantification of standardized uptake values (SUVs) from static PET images revealed a twofold increase in the PET signal in LLC tumors irradiated with two fractions of medium-dose RT (2 × 6 Gy). Ex vivo analysis confirmed the low abundance of FAP+ cells in tumors and demonstrated similar RT-induced changes in CAF levels across the different models.

conclusionsOur findings suggest that CAFs constitute a relatively small cell population in subcutaneously transplanted tumor models, and that fractionated radiotherapy may induce a moderate increase in FAP+ cells in LLC tumors. Additionally, we demonstrated that [18F]AlF-FAPI-74 is a reliable biomarker for evaluating the number of FAP+ stromal cells in tumors and for addressing potential therapy-induced changes in CAFs.

Indexed as

Cancer-Associated FibroblastsGelatinasesMembrane ProteinsPositron-Emission TomographySerine EndopeptidasesAnimalsCell Line, TumorEndopeptidasesFemaleFibroblast Activation Protein AlphaMiceRadiopharmaceuticalsTumor MicroenvironmentEndopeptidasesFibroblast Activation Protein AlphaGelatinasesMembrane ProteinsRadiopharmaceuticalsSerine Endopeptidases

Identifiers

PMID41761350
PMCPMC13049841

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.