HCAR2 as a Radioligand Therapy Target
HCAR2, hydroxycarboxylic acid receptor 2, is a cell-surface protein (GPCR). In Human Protein Atlas immunohistochemistry, HCAR2 staining is highest in head and neck cancer (67% of samples positive), bladder cancer (73% of samples positive) and gastric cancer (50% of samples positive). Evidence on whether HCAR2 internalizes is mixed. Clinical status: Clinical-stage (up to phase 2, any modality).
Is HCAR2 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: Medium IHC staining in head and neck cancer, 67% of samples positive.
- ⚠️ Internalization: Mixed evidence.
- ✅ Clinical precedent: Clinical-stage (up to phase 2, any modality)
- ❔ Shedding: Not yet assessed.
- ❔ Normal-tissue dosimetry: Check kidney, liver, bone marrow and salivary expression in the Human Protein Atlas tissue atlas.
HCAR2 expression in cancer
Protein expression of HCAR2 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 |
|---|---|---|---|
| Head and Neck Cancer | 0.33 | Medium | 67% |
| Bladder Cancer | 0.30 | Medium | 73% |
| Gastric Cancer | 0.19 | Low | 50% |
| Pancreatic Cancer | 0.15 | Low | 46% |
| Kidney Cancer | 0.12 | Low | 36% |
| Breast Cancer | 0.12 | Low | 27% |
| Lung Cancer | 0.12 | Low | 27% |
| Liver Cancer | 0.11 | Low | 33% |
| Testicular Cancer | 0.08 | Low | 25% |
| Ovarian Cancer | 0.06 | Low | 18% |
| Colorectal Cancer | 0.06 | Low | 17% |
| Cervical Cancer | 0.06 | Low | 17% |
| Prostate Cancer | 0.06 | Low | 17% |
| Endometrial Cancer | 0.06 | Low | 17% |
| Skin Cancer | 0.03 | Low | 8% |
| Lymphoma | 0.03 | Low | 8% |
Not detected by IHC in: melanoma, thyroid cancer, neuroendocrine tumors, glioma.
Is HCAR2 internalized?
Uncertain. Insufficient literature found.
HCAR2 clinical trials
Clinical-stage (up to phase 2, any modality). Nuclens hasn't indexed trials for HCAR2 yet. Search ClinicalTrials.gov for HCAR2 trials.
HCAR2 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 HCAR2 in the Human Protein Atlas tissue atlas, and read how normal-tissue expression predicts radioligand dosimetry risk.
HCAR2 gene essentiality (DepMap)
CRISPR knockout effect across 1252 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 head and neck cancer radioligand targets
EGFR · c-MET (MET) · HER3 (ERBB3) · ITGAV · SSTR2 · B7-H3 (CD276) · STEAP2 · Mesothelin (MSLN)
See all radioligand therapy targets in head and neck cancer.
See how HCAR2 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.