HTR3B as a Radioligand Therapy Target
HTR3B, 5-hydroxytryptamine receptor 3B, is a cell-surface protein (GPCR). In Human Protein Atlas immunohistochemistry, HTR3B staining is highest in testicular cancer (100% of samples positive), melanoma (91% of samples positive) and colorectal cancer (92% of samples positive). Evidence on whether HTR3B internalizes is mixed. Clinical status: Clinical-stage (up to phase 3, any modality).
Is HTR3B 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 testicular cancer, 100% of samples positive.
- ⚠️ Internalization: Mixed evidence.
- ✅ 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.
HTR3B expression in cancer
Protein expression of HTR3B 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 |
|---|---|---|---|
| Testicular Cancer | 0.70 | High | 100% |
| Melanoma | 0.70 | High | 91% |
| Colorectal Cancer | 0.64 | High | 92% |
| Pancreatic Cancer | 0.61 | High | 83% |
| Gastric Cancer | 0.58 | High | 100% |
| Lung Cancer | 0.58 | High | 82% |
| Ovarian Cancer | 0.52 | High | 82% |
| Endometrial Cancer | 0.44 | Medium | 92% |
| Skin Cancer | 0.44 | Medium | 67% |
| Head and Neck Cancer | 0.42 | Medium | 75% |
| Prostate Cancer | 0.39 | Medium | 82% |
| Bladder Cancer | 0.39 | Medium | 73% |
| Liver Cancer | 0.36 | Medium | 67% |
| Lymphoma | 0.36 | Medium | 58% |
| Breast Cancer | 0.30 | Medium | 55% |
| Cervical Cancer | 0.25 | Medium | 58% |
| Glioma | 0.21 | Medium | 55% |
| Thyroid Cancer | 0.17 | Low | 25% |
| Kidney Cancer | 0.12 | Low | 27% |
| Neuroendocrine Tumors | 0.11 | Low | 33% |
Is HTR3B internalized?
Uncertain. Insufficient literature found.
HTR3B clinical trials
Clinical-stage (up to phase 3, any modality). Nuclens hasn't indexed trials for HTR3B yet. Search ClinicalTrials.gov for HTR3B trials.
HTR3B 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 HTR3B in the Human Protein Atlas tissue atlas, and read how normal-tissue expression predicts radioligand dosimetry risk.
HTR3B gene essentiality (DepMap)
CRISPR knockout effect across 1222 cancer cell lines: 0.09 (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 testicular cancer radioligand targets
HER3 (ERBB3) · c-MET (MET) · STEAP2 · KIT · SSTR2 · TMEFF2 · Mesothelin (MSLN) · HER2 (ERBB2)
See all radioligand therapy targets in testicular cancer.
See how HTR3B ranks against 15,000 targets for your indication.
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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.