SMOX as a Radioligand Therapy Target
SMOX, spermine oxidase, is a cell-surface protein (GPCR). In Human Protein Atlas immunohistochemistry, SMOX staining is highest in kidney cancer (100% of samples positive), thyroid cancer (100% of samples positive) and neuroendocrine tumors (100% of samples positive). Evidence on whether SMOX internalizes is mixed. Clinical status: Discovery-stage (no clinical drug program).
Is SMOX 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 kidney cancer, 100% of samples positive.
- ⚠️ Internalization: Mixed evidence.
- ⚠️ Clinical precedent: Discovery-stage (no clinical drug program)
- ❔ Shedding: Not yet assessed.
- ❔ Normal-tissue dosimetry: Check kidney, liver, bone marrow and salivary expression in the Human Protein Atlas tissue atlas.
SMOX expression in cancer
Protein expression of SMOX 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 |
|---|---|---|---|
| Kidney Cancer | 0.97 | High | 100% |
| Thyroid Cancer | 0.92 | High | 100% |
| Neuroendocrine Tumors | 0.83 | High | 100% |
| Pancreatic Cancer | 0.81 | High | 100% |
| Ovarian Cancer | 0.79 | High | 100% |
| Liver Cancer | 0.79 | High | 100% |
| Endometrial Cancer | 0.78 | High | 100% |
| Melanoma | 0.76 | High | 100% |
| Head and Neck Cancer | 0.75 | High | 100% |
| Lymphoma | 0.75 | High | 100% |
| Glioma | 0.75 | High | 100% |
| Breast Cancer | 0.73 | High | 100% |
| Skin Cancer | 0.72 | High | 100% |
| Colorectal Cancer | 0.72 | High | 100% |
| Bladder Cancer | 0.72 | High | 100% |
| Lung Cancer | 0.72 | High | 100% |
| Prostate Cancer | 0.70 | High | 100% |
| Testicular Cancer | 0.69 | High | 100% |
| Gastric Cancer | 0.64 | High | 100% |
| Cervical Cancer | 0.61 | High | 100% |
Is SMOX internalized?
Uncertain. Insufficient literature found.
SMOX clinical trials
Discovery-stage (no clinical drug program). Nuclens hasn't indexed trials for SMOX yet. Search ClinicalTrials.gov for SMOX trials.
SMOX 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 SMOX in the Human Protein Atlas tissue atlas, and read how normal-tissue expression predicts radioligand dosimetry risk.
SMOX gene essentiality (DepMap)
CRISPR knockout effect across 1258 cancer cell lines: -0.01 (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 kidney cancer radioligand targets
EGFR · c-MET (MET) · HER3 (ERBB3) · STEAP2 · ITGAV · Mesothelin (MSLN) · SSTR2 · HER2 (ERBB2)
See all radioligand therapy targets in kidney cancer.
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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.