FLT4 as a Radioligand Therapy Target
FLT4, fms related receptor tyrosine kinase 4, is a cell-surface protein (RTK). In Human Protein Atlas immunohistochemistry, FLT4 staining is highest in thyroid cancer (100% of samples positive), prostate cancer (92% of samples positive) and liver cancer (92% of samples positive). Published literature reports that FLT4 internalizes after ligand binding, which helps retain a radionuclide inside tumor cells. Clinical status: Clinical-stage (up to phase 3, any modality).
Is FLT4 a good radioligand therapy target?
Scored against the six criteria that decide whether a protein can become a radioligand therapy:
- ✅ Cell-surface accessibility: Localized to the cell surface, so a radioligand can reach it from circulation.
- ✅ Tumor expression: High IHC staining in thyroid cancer, 100% of samples positive.
- ✅ Internalization: Reported to internalize, which favors radionuclide retention.
- ✅ Clinical precedent: Clinical-stage (up to phase 3, any modality)
- ❔ Shedding: Not yet assessed.
- ❔ Normal-tissue dosimetry: Check kidney, liver, bone marrow and salivary expression in the Human Protein Atlas tissue atlas.
FLT4 expression in cancer
Protein expression of FLT4 across 20 cancer types from Human Protein Atlas immunohistochemistry. The score is a weighted staining intensity from 0 to 1; "% positive" is the share of patient samples with detectable staining.
| Cancer type | IHC score | Level | % positive |
|---|---|---|---|
| Thyroid Cancer | 0.67 | High | 100% |
| Prostate Cancer | 0.56 | High | 92% |
| Liver Cancer | 0.47 | Medium | 92% |
| Breast Cancer | 0.47 | Medium | 80% |
| Neuroendocrine Tumors | 0.44 | Medium | 100% |
| Pancreatic Cancer | 0.36 | Medium | 50% |
| Kidney Cancer | 0.24 | Medium | 55% |
| Colorectal Cancer | 0.22 | Medium | 50% |
| Testicular Cancer | 0.19 | Low | 58% |
| Head and Neck Cancer | 0.17 | Low | 50% |
| Glioma | 0.17 | Low | 25% |
| Gastric Cancer | 0.14 | Low | 25% |
| Skin Cancer | 0.13 | Low | 30% |
| Melanoma | 0.11 | Low | 33% |
| Endometrial Cancer | 0.11 | Low | 25% |
| Lung Cancer | 0.08 | Low | 17% |
| Ovarian Cancer | 0.06 | Low | 8% |
| Bladder Cancer | 0.06 | Low | 8% |
| Cervical Cancer | 0.03 | Low | 8% |
Not detected by IHC in: lymphoma.
Is FLT4 internalized?
Yes. AML patients who expressed high cytosolic FLT4 were linked to an AML-refractory status by internalization mechanism.
Sources: PMID 37317880 · PMID 30416855 · PMID 28356442. AI-extracted from abstracts, so verify before citing.
FLT4 clinical trials
Clinical-stage (up to phase 3, any modality). Nuclens hasn't indexed trials for FLT4 yet. Search ClinicalTrials.gov for FLT4 trials.
FLT4 normal tissue expression
Normal-tissue expression in dose-limiting organs (kidney, liver, bone marrow, salivary glands) drives radioligand dosimetry risk. Nuclens is re-validating its normal-tissue values, so they are not shown here yet. See FLT4 in the Human Protein Atlas tissue atlas, and read how normal-tissue expression predicts radioligand dosimetry risk.
FLT4 gene essentiality (DepMap)
CRISPR knockout effect across 1247 cancer cell lines: 0.02 (not essential). Radioligands kill by radiation, not by blocking the target, so essentiality matters less than for inhibitors. A non-essential target can still be an excellent radioligand target.
Related thyroid cancer radioligand targets
c-MET (MET) · HER3 (ERBB3) · EPCAM · SSTR2 · EGFR · ITGAV · STEAP2 · FAP
See all radioligand therapy targets in thyroid cancer.
See how FLT4 ranks against 15,000 targets for your indication.
Run a free analysisData sources
Subcellular localization: UniProt via Open Targets (CC BY 4.0 / CC0). Tumor immunohistochemistry: Human Protein Atlas (CC BY-SA 4.0). Clinical trials: ClinicalTrials.gov (public domain). Gene essentiality: DepMap (CC BY 4.0). Internalization and shedding: AI-extracted from PubMed abstracts, so verify against the cited papers before relying on them. Nuclens is a first-pass triage layer, not a substitute for wet-lab validation or clinical dosimetry. Derived expression data on this page is shared under CC BY-SA 4.0.