SSTR2 as a Radioligand Therapy Target
SSTR2, somatostatin receptor 2, is a cell-surface protein (GPCR). In Human Protein Atlas immunohistochemistry, SSTR2 staining is highest in liver cancer (92% of samples positive), thyroid cancer (100% of samples positive) and neuroendocrine tumors (100% of samples positive). Published literature reports that SSTR2 internalizes after ligand binding, which helps retain a radionuclide inside tumor cells. Clinical status: FDA-approved radioligand therapy, with 1 active clinical trial.
Is SSTR2 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 liver cancer, 92% of samples positive.
- ✅ Internalization: Reported to internalize, which favors radionuclide retention.
- ✅ Clinical precedent: FDA-approved radioligand therapy
- ❔ Shedding: Not yet assessed.
- ❔ Normal-tissue dosimetry: Check kidney, liver, bone marrow and salivary expression in the Human Protein Atlas tissue atlas.
SSTR2 expression in cancer
Protein expression of SSTR2 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 |
|---|---|---|---|
| Liver Cancer | 0.56 | High | 92% |
| Thyroid Cancer | 0.50 | Medium | 100% |
| Neuroendocrine Tumors | 0.50 | Medium | 100% |
| Gastric Cancer | 0.50 | Medium | 83% |
| Colorectal Cancer | 0.47 | Medium | 92% |
| Bladder Cancer | 0.47 | Medium | 92% |
| Head and Neck Cancer | 0.42 | Medium | 75% |
| Skin Cancer | 0.42 | Medium | 67% |
| Melanoma | 0.39 | Medium | 75% |
| Endometrial Cancer | 0.33 | Medium | 73% |
| Cervical Cancer | 0.31 | Medium | 75% |
| Pancreatic Cancer | 0.31 | Medium | 58% |
| Glioma | 0.21 | Medium | 46% |
| Breast Cancer | 0.18 | Low | 55% |
| Lung Cancer | 0.17 | Low | 42% |
| Lymphoma | 0.14 | Low | 42% |
| Testicular Cancer | 0.11 | Low | 25% |
| Ovarian Cancer | 0.08 | Low | 25% |
| Prostate Cancer | 0.08 | Low | 17% |
| Kidney Cancer | 0.06 | Low | 18% |
Is SSTR2 internalized?
Yes. This striking discordance unveils agonists' internalization trap-prolonged DOTANOC retention through SSTR2 endocytosis in estrogen-primed fibroids.
Sources: PMID 42149618 · PMID 41928014 · PMID 41900872 · PMID 41868663 · PMID 40883440. AI-extracted from abstracts, so verify before citing.
SSTR2 clinical trials
FDA-approved radioligand therapy. 1 active trial reference SSTR2 (ClinicalTrials.gov, accessed 2026-06-29).
SSTR2 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 SSTR2 in the Human Protein Atlas tissue atlas, and read how normal-tissue expression predicts radioligand dosimetry risk.
SSTR2 gene essentiality (DepMap)
CRISPR knockout effect across 1258 cancer cell lines: -0.11 (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 liver cancer radioligand targets
EGFR · c-MET (MET) · HER3 (ERBB3) · STEAP2 · HER2 (ERBB2) · Mesothelin (MSLN) · B7-H3 (CD276) · TMEFF2
See all radioligand therapy targets in liver cancer.
See how SSTR2 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.