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CADM2 / Cell adhesion molecule 2 · IHC design guide
Design Immunohistochemistry for CADM2
Plan CADM2 IHC-P using cerebellar synaptic glomeruli and cortical neuropil as expected positive staining sites (HPA tissue IHC). This guide covers controls, fixation, antibody dilution and interpretation of paraffin-section staining.
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
CADM2 Immunohistochemistry Experimental Design Guide
Expected localisation, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before staining
| Expected localisation | Cerebellar synaptic glomeruli and cortical neuropil (HPA tissue IHC) | |
| Staining pattern | High in glomerular cores and cortical neuropil (HPA tissue IHC) | |
| Antigen retrieval | Tris-EDTA pH 9.0 HIER, heat-mediated (datasheet A06688-1) | |
| Positive control | Cerebellum+1 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A06688-1) | |
| Caveat | Caudate glial cells are undetected despite CNS staining elsewhere (HPA tissue IHC) | |
| Regulation | Expression regulation not annotated (UniProt) | |
| Isoform / epitope | 5 isoforms; check extracellular versus cytoplasmic epitope coverage (UniProt) |
Section 1
Recommended CADM2 IHC & IF Protocols
The catalog antibody protocol uses heat-mediated Tris-EDTA retrieval at pH 9.0 (datasheet: A06688-1). Two published CADM2 IHC protocols provide additional paraffin-section conditions (PMC8081990; PMC11239024).
| Sample | Paraffin-embedded human tonsil tissue; fixative not specified (datasheet A06688-1) |
| Fixation | Image fixative and duration unreported (datasheet A06688-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Tris-EDTA pH 9.0 (datasheet A06688-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% normal serum of the secondary host, 30 min, room temperature (standard) |
| Primary antibody | Rabbit anti-CADM2, 1:100-1:300 (datasheet A06688-1) |
| Primary incubation | Overnight at 4 °C (standard) |
| Detection | HRP-polymer secondary, DAB chromogen 5–10 min (standard) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | CADM2-positive staining in synaptic glomeruli - core of cerebellum (HPA tissue IHC: High). HPA tissue profile: Distinct expression in CNS and peripheral nerve fibers. No signal in the no-primary control. |
💡Decision noteStart with Tris-EDTA pH 9.0 for the catalog antibody (datasheet: A06688-1); citrate retrieval is a published alternative with a different antibody (PMC11239024: IHC methods).
Section 2
What Is the Expected CADM2 Staining Pattern?
CADM2 is a single-pass membrane protein associated with synapses and axons; UniProt also reports it in the axoplasm of myelinated axons (UniProt Q8N3J6 location and topology). In IHC, expect staining in cerebellar synaptic glomerulus cores and cerebral cortical neuropil, both reported High by HPA (HPA tissue IHC). HPA describes the tissue pattern as distinct in the CNS and peripheral nerve fibers, with Enhanced IHC reliability (HPA tissue IHC).
| Strong staining in cerebellar synaptic glomerulus cores and cortical neuropil. | This matches the reported High IHC pattern in both structures (HPA tissue IHC). Interpret the structures on the section; HPA does not establish that every nearby cell should stain. |
| Signal follows neural processes or synaptic regions rather than filling nuclei. | This fits the annotated membrane, synapse and axon locations (UniProt Q8N3J6 location). UniProt also reports axoplasmic CADM2, so an axonal signal need not form a sharp membrane outline. |
| Prominent nuclear staining dominates the section. | A nuclear pattern conflicts with the reported membrane, synapse and axon locations (UniProt Q8N3J6 location). Treat it as suspect and compare it with the same-run positive control before interpreting it as CADM2. |
| Adipocytes or glandular cells stain strongly despite the expected neural pattern. | HPA reports CADM2 as Not detected in adipose adipocytes and several sampled glandular cell populations (HPA tissue IHC). Check for cross-reactivity or endogenous detection activity; an unexpected positive alone does not identify its cause. |
| Diffuse staining covers structures that should remain distinct, or a known-positive neural region has no signal. | Diffuse background obscures the reported neural pattern; absence of signal in cerebellar glomerulus cores or cortical neuropil conflicts with HPA's High IHC observations (HPA tissue IHC). Resolve the control result before scoring the test section. |
💡Expected CADM2 appearanceCall a section positive when clear, High signal highlights cerebellar synaptic glomerulus cores or cortical neuropil (HPA tissue IHC); dominant nuclear staining or broad staining of HPA negative cell populations is suspect (UniProt Q8N3J6 location; HPA tissue IHC).
| Compartment and epitope location | CADM2 spans the membrane at residues 368–388, with extracellular residues 25–367 and cytoplasmic residues 389–435 (UniProt Q8N3J6 topology). Antibody epitope location was not supplied, so the topology cannot predict this antibody's retrieval response. |
| Processing and modification | UniProt lists a signal peptide at residues 1–24 and glycosylation sites at 31, 51 and 291 (UniProt Q8N3J6 processing and glycosylation). These annotations do not establish epitope masking, shedding or fixation sensitivity for this IHC assay. |
| Isoforms | UniProt lists 5 CADM2 isoforms (UniProt Q8N3J6 isoforms). With no antibody epitope or isoform coverage supplied, a staining difference cannot be assigned to a specific isoform. |
| Strength of tissue evidence | HPA rates the tissue IHC pattern Enhanced and describes high consistency between staining and RNA data (HPA tissue IHC reliability). This supports the listed neural controls, but does not make every unlisted tissue an established negative. |
| IF/ICC: Is the IHC pattern an IF control? | No ICC-IF images or antibody ICC validation are supplied, although HPA summarizes the subcellular location as membrane (HPA subcellular; HPA antibody record). Use the separate IF/ICC guide for that application; the IHC observations do not validate an IF result. |
| Situation | Likely cause | Next action |
|---|---|---|
| No staining in a cerebellar or cortical positive control. | A failed detection run or unsuitable assay conditions are possible; HPA reports High staining in the specified neural structures (HPA tissue IHC). | Confirm that the expected structure is present, then review the antibody dilution, retrieval and detection steps against the IHC-validated antibody's instructions (standard IHC practice). No CADM2-specific retrieval condition is supplied. |
| Strong nuclear signal dominates while the neural pattern is weak. | Nuclear dominance conflicts with CADM2's reported membrane, synapse and axon locations (UniProt Q8N3J6 location). | Compare the same-run neural positive control and a primary-omission control; inspect blocking and detection background before scoring nuclear signal as specific (standard IHC practice). |
| Adipocytes or sampled glandular cells stain strongly. | These cell populations are reported Not detected in the listed HPA tissues (HPA tissue IHC); cross-reactivity or endogenous detection activity may contribute. | Compare the same cell population with a primary-omission control, and check endogenous-enzyme blocking when using enzyme-based chromogenic detection (standard IHC practice). |
| Chromogen coats the section and obscures neuropil boundaries. | Diffuse background prevents comparison with the distinct cortical neuropil pattern reported by HPA (HPA tissue IHC). Its source cannot be determined from appearance alone. | Check the primary-omission control and review blocking, wash steps and antibody dilution under the chosen IHC method (standard IHC practice). |
| A nerve-like signal appears without a crisp cell-surface outline. | UniProt places CADM2 at the membrane and axon and also reports it in myelinated-axon axoplasm (UniProt Q8N3J6 location). A sharp outline is therefore not the sole acceptable neural appearance. | Assess whether staining tracks recognizable neural structures and agrees with the same-run positive control; avoid calling it false solely because the outline is indistinct (UniProt Q8N3J6 location; HPA tissue IHC). |
| A test tissue is negative while the neural positive control stains. | HPA establishes High staining in selected neural structures, but supplies no universal expectation for all tissues (HPA tissue IHC). | Score the test tissue against its own identifiable cell populations and the working control; report absence of detectable signal without inferring CADM2 loss or a fixation effect from this evidence alone. |
Experiment evidence
IHC & IF images showing CADM2 staining
A06688-1 · IHCImmunohistochemical analysis of paraffin-embedded human tonsil. 1, Tris-EDTA, pH9.0 was used for antigen retrieval. 2 Antibody was diluted a
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000175161-CADM2/tissue/cerebral+cortex#imid_19814421
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000175161-CADM2/tissue/colon#imid_19814331
HPA · RectumHuman Protein Atlas IHC, Rectum. Source: https://www.proteinatlas.org/ENSG00000175161-CADM2/tissue/rectum#imid_19814307
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000175161-CADM2/tissue/liver#imid_19814340
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for CADM2 IHC & IF
🧪Run cerebellum first and look for staining in synaptic glomeruli cores (HPA: High in synaptic glomeruli cores). Use adipose tissue as the negative tissue and check that its adipocytes remain unstained (HPA: Not detected in adipocytes); on the cerebellar slide, use areas outside the stained cores to assess background, without assuming every surrounding cell is CADM2-negative.
Positive control tissue: Cerebellum (Synaptic glomeruli - core, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for CADM2; derive a cell-line control from the positive tissue's cell type (Synaptic glomeruli - core) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary (secondary-only) control, a host-species-matched isotype control for a monoclonal antibody or nonimmune IgG control for a polyclonal antibody, and CADM2-knockout tissue as a biological negative (standard IHC practice). Block endogenous peroxidase for chromogenic detection; if assessing brain tissue by IF, check autofluorescence with an unstained section (standard IHC/IF practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported in the supplied evidence, and the selected A06688-1 paraffin-section caption does not state a fixative (selected-SKU tissue-IHC caption: fixative not stated). The caption uses Tris-EDTA retrieval at pH 9.0 and a 1:200 primary-antibody dilution, but it does not establish whether CADM2 staining depends on that retrieval condition (selected-SKU tissue-IHC caption). Whether frozen sections or IF would be easier is undetermined from the supplied evidence; in brain sections, dense synaptic staining can make cell-level attribution difficult, and autofluorescence can complicate IF interpretation (HPA: High in cerebellar synaptic glomeruli cores and cerebral cortical neuropil; standard IF practice).
HPA tissue IHC evidence for CADM2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — High consistency between antibody staining and RNA expression data.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Cerebellum | Synaptic glomeruli - core | High | Protein (IHC) | HPA → |
| Cerebral cortex | Neuropil | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced CADM2 IHC Tips
Troubleshoot CADM2 staining in paraffin section IHC using the catalog antibody’s tissue image and the reported neural distribution as separate lines of evidence.
Which antigen retrieval should I start with for CADM2 paraffin sections?
Start with heat-mediated Tris-EDTA at pH 9.0 for CADM2 paraffin sections (datasheet A06688-1). The catalog antibody’s human tonsil image used that retrieval, followed by primary antibody at 1:200 overnight at 4°C and secondary antibody at 1:200 for 45 minutes at room temperature (datasheet A06688-1). Keep section thickness, heating, cooling, and detection conditions consistent while comparing retrieval runs (standard IHC practice). If staining is weak, compare a milder retrieval condition on adjacent sections while retaining the catalog condition as the reference; assess tissue preservation and background alongside signal (standard IHC practice).
How should I troubleshoot fixation when CADM2 staining is weak?
The catalog image identifies paraffin-embedded human tonsil but does not report its fixative, so target-specific fixation sensitivity is unknown (datasheet A06688-1). Record the fixative, fixation duration, and processing history for each specimen before comparing staining across cases (standard IHC practice). Run sections with differing documented processing histories together, using the same pH 9.0 retrieval and detection conditions to distinguish a processing association from a staining-run difference (datasheet A06688-1; standard IHC practice). Do not assign a weak result to CADM2-specific masking without matched specimens and an independent control; inspect morphology and section integrity before changing conditions (standard IHC practice).
Where should convincing CADM2 staining appear in neural tissue?
Prioritise staining associated with cell surfaces, synapses, and axons when reviewing CADM2 chromogenic sections (UniProt Q8N3J6 localisation). CADM2 spans the membrane at residues 368–388, with an extracellular region at 25–367 and a cytoplasmic region at 389–435 (UniProt Q8N3J6 topology). Reported tissue staining is high in cerebellar synaptic glomerulus cores and cerebral cortical neuropil, with a broader pattern in central nervous system and peripheral nerve fibers (HPA: tissue IHC). Axoplasmic staining can also be compatible with the annotation, so judge a fiber pattern in its anatomical context and compare it with neighbouring tissue structures (UniProt Q8N3J6 localisation; standard IHC practice).
Could the antibody epitope explain discordant CADM2 staining patterns?
Map the antibody’s stated immunogen or epitope against CADM2 before comparing sections or antibodies; no epitope position is supplied for the catalog antibody here (datasheet A06688-1). CADM2 has 5 listed isoforms and an extracellular region at residues 25–367, a transmembrane segment at 368–388, and a cytoplasmic tail at 389–435 (UniProt Q8N3J6). Its extracellular region contains Ig-like domains and glycosylation sites at 31, 51, and 291, which make epitope location relevant to interpreting a discrepancy without establishing the cause (UniProt Q8N3J6). Check whether the claimed epitope is shared by the isoforms under comparison before attributing staining differences to expression (UniProt Q8N3J6 isoforms; standard IHC practice).
How can I assess CADM2 by IF alongside a neural marker?
Treat IF as a separately optimised application because the supplied catalog image documents paraffin section IHC, and no ICC/IF images are listed in the supplied subcellular record (datasheet A06688-1; HPA: subcellular). Multiplex CADM2 with a neuronal or axonal marker appropriate to the structure being evaluated, and include single-stain controls to assess channel bleed-through (UniProt Q8N3J6 localisation; standard IF practice). Choose fluorophores after checking tissue autofluorescence, favouring a spectrally separated far-red channel when background makes shorter wavelengths difficult to read (standard IF practice). Confirm the antibody’s epitope side before setting permeabilisation: extracellular epitopes may be assessed without it, whereas access to the cytoplasmic region at 389–435 requires it (UniProt Q8N3J6 topology; standard IF practice).
What should I change if CADM2 DAB staining is diffuse?
First inspect a no-primary control and the section’s edges to separate detection background from a reproducible anatomical pattern (standard IHC practice). Check the peroxidase block, blocking step, washes, secondary antibody, and DAB development under the same conditions used for the test section (standard chromogenic IHC practice). The catalog image reports primary antibody at 1:200 overnight at 4°C and secondary antibody at 1:200 for 45 minutes at room temperature; these are image conditions, not proof of specificity in every tissue (datasheet A06688-1). Compare diffuse colour with the reported neuropil and synaptic glomerulus patterns before increasing antibody concentration (HPA: tissue IHC; standard IHC practice).
How should I score CADM2 across paraffin section specimens? ⚠ ANSWER MARKED FOR VERIFICATION
Define the anatomical region and compartment before scoring, because reported CADM2 signal includes cerebral cortical neuropil and cerebellar synaptic glomerulus cores (HPA: tissue IHC). For discrete positive cells, record percent positive cells and an H-score using consistent intensity categories; for nerve fibers or neuropil, measure positive area or signal density per mm² within a defined region (standard IHC quantification practice). Normalise to viable tissue area or the corresponding compartment area, and keep section thickness, imaging, thresholding, and DAB development consistent across cases (standard IHC quantification practice). Include negative-control staining and exclude folds, edges, and necrotic areas from measurements, documenting exclusions before comparing groups (standard IHC practice).
How do I distinguish genuine CADM2 staining from artefact?
A convincing result follows relevant neural structures, particularly cortical neuropil, cerebellar synaptic glomerulus cores, or nerve fibers, and agrees with the membrane, synaptic, or axonal annotation (HPA: tissue IHC; UniProt Q8N3J6 localisation). Diffuse staining in unrelated compartments should prompt review of tissue morphology, the no-primary control, and antibody specificity before it is called CADM2 (standard IHC interpretation practice). Examine intense staining confined to section edges or necrotic tissue as a possible artefact, and assess colour in the no-primary control for endogenous enzyme or detection background (standard chromogenic IHC practice). HPA reports CADM2 as not detected in adipocytes of adipose tissue, which offers a tissue-pattern comparison but does not replace controls in the specimen being interpreted (HPA: tissue IHC).
Boster reagents
Best CADM2 / Cell adhesion molecule 2 IHC Antibodies
A06688-1 has real IHC data from paraffin-embedded human tonsil (IHC image caption). IF is listed without an IF image (catalog applications; IF image alts); Human, Mouse and Rat reactivity is listed (catalog reactivity).
Real IHC data
Anti-IGSF4D CADM2 Antibody
Cat # A06688-1
A06688-1 will render with an IHC image of paraffin-embedded human tonsil (IHC image caption). The catalog lists IHC and IF applications and Human, Mouse and Rat reactivity for A06688-1; IF image data are unreported (catalog applications, reactivity and IF image alts).
Which to pick: For tissue IHC, choose A06688-1 for paraffin sections: its human tonsil image used Tris-EDTA retrieval at pH 9.0 and primary antibody at 1:200 overnight; the fixative is unreported (IHC image caption). For IF, A06688-1 lists a 1:200–1:1000 dilution, while ICC validation and an IF image are unreported (catalog applications, dilutions and IF image alts). For cross-species work, A06688-1 lists Human, Mouse and Rat reactivity; its host is rabbit, and clonality is unreported (catalog reactivity, host and clone).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q8N3J6 (CADM2_HUMAN, Cell adhesion molecule 2).
- Human Protein Atlas. CADM2 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. CADM2 subcellular location (ICC-IF): Membrane.
- Human Protein Atlas. CADM2 antibody validation summary (1 antibodies).
- FOXO3a inhibits the EMT and metastasis of breast cancer by regulating TWIST-1 mediated miR-10b/CADM2 axis. Translational oncology 2021 — PMC8081990.
- CircDDX17 inhibits invasive progression of pituitary adenomas by sponging miR-1279 and regulating CADM2 expression. Frontiers in oncology 2023 — PMC10646483.
- Regulation of body weight and energy homeostasis by neuronal cell adhesion molecule 1. Nature neuroscience 2017 — PMC5533218.
- Quercetin inhibits the epithelial-mesenchymal transition and reverses CDK4/6 inhibitor resistance in breast cancer by regulating circHIAT1/miR-19a-3p/CADM2 axis. PloS one 2024 — PMC11239024.
- PubMed PMID:21864505 — UniProt-cited evidence.
- PubMed PMID:17974005 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for CADM2 (Cell adhesion molecule 2). Expected localisation Cerebellar synaptic glomeruli and cortical neuropil (HPA tissue IHC). Antigen retrieval: Tris-EDTA pH 9.0 HIER, heat-mediated (datasheet A06688-1). Validated IHC antibody: A06688-1 at 1:100-1:300 (the product's own IHC validation image is shown). Controls (HPA): positive Cerebellum (Synaptic glomeruli - core); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human tonsil tissue; fixative not specified (datasheet A06688-1); 2. Fixation: Image fixative and duration unreported (datasheet A06688-1); verify before use.; 3. Sectioning: 4–5 µm sections on charged slides (standard); 4. Deparaffinisation: Xylene, graded ethanol series to water (standard); 5. Antigen retrieval: Heat retrieval: Tris-EDTA pH 9.0 (datasheet A06688-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% normal serum of the secondary host, 30 min , room temperature (standard); 8. Primary antibody: Rabbit anti-CADM2, 1:100-1:300 (datasheet A06688-1); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A06688-1); Caveat: Caudate glial cells are undetected despite CNS staining elsewhere (HPA tissue IHC); Isoform / epitope: 5 isoforms; check extracellular versus cytoplasmic epitope coverage (UniProt); Regulation: Expression regulation not annotated (UniProt). Evidence: UniProt Q8N3J6, HPA tissue IHC · Enhanced, HPA ICC-IF · Membrane, Datasheet A06688-1, PMC8081990, PMC11239024. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/CADM2/immunohistochemistry-ihc-guide.