CHRM1 as a Radioligand Therapy Target
CHRM1, cholinergic receptor muscarinic 1, is a cell-surface protein (GPCR). In Human Protein Atlas immunohistochemistry, CHRM1 staining is highest in glioma (56% of samples positive), neuroendocrine tumors (25% of samples positive) and melanoma (17% of samples positive). Evidence on whether CHRM1 internalizes is mixed. Clinical status: Clinical-stage (up to phase 3, any modality).
Is CHRM1 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 glioma, 56% 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.
CHRM1 expression in cancer
Protein expression of CHRM1 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 |
|---|---|---|---|
| Glioma | 0.22 | Medium | 56% |
| Neuroendocrine Tumors | 0.08 | Low | 25% |
| Melanoma | 0.06 | Low | 17% |
| Endometrial Cancer | 0.03 | Low | 9% |
Not detected by IHC in: skin cancer, colorectal cancer, head and neck cancer, ovarian cancer, lymphoma, breast cancer, kidney cancer, thyroid cancer, bladder cancer, cervical cancer, lung cancer, pancreatic cancer, prostate cancer, gastric cancer, testicular cancer, liver cancer.
Is CHRM1 internalized?
Uncertain. The abstract mentions alterations in 'protein internalization' and 'translocation to and from the membrane' regarding muscarinic receptor proteins, but it does not provide direct evidence confirming that CHRM1 specifically undergoes internalization or endocytosis upon ligand or antibody binding.
Sources: PMID 41980822 · PMID 41659549 · PMID 24829147. AI-extracted from abstracts, so verify before citing.
CHRM1 clinical trials
Clinical-stage (up to phase 3, any modality). Nuclens hasn't indexed trials for CHRM1 yet. Search ClinicalTrials.gov for CHRM1 trials.
CHRM1 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 CHRM1 in the Human Protein Atlas tissue atlas, and read how normal-tissue expression predicts radioligand dosimetry risk.
CHRM1 gene essentiality (DepMap)
CRISPR knockout effect across 1240 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 glioma radioligand targets
EGFR · HER3 (ERBB3) · c-MET (MET) · ITGAV · B7-H3 (CD276) · SSTR2 · STEAP2 · FAP
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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.