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PVR / Poliovirus receptor · IHC design guide
Design Immunohistochemistry for PVR
Plan PVR staining in paraffin sections using the IHC-validated antibody and chromogenic detection. Compare high-staining cardiomyocytes or decidual cells with unstained adipocytes, and score membrane and cytoplasmic signal (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
PVR 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 | Membrane and cytoplasmic staining in several tissues (HPA tissue IHC) | |
| Staining pattern | Membranous and cytoplasmic staining across several tissues (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet M00664-2) | |
| Positive control | Heart muscle+4 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections. (standard IHC practice; not target-specific) | |
| Caveat | Secreted variants may complicate tissue staining (HPA tissue IHC) | |
| Regulation | No specific regulator annotated (UniProt) | |
| Isoform / epitope | 4 isoforms; check extracellular vs cytoplasmic epitope (UniProt) |
Section 1
Recommended PVR IHC & IF Protocols
The catalog antibody has an IHC-P protocol (datasheet: M00664-2); a published lung squamous cell carcinoma TMA study provides a chromogenic comparison (PMC9352965).
| Sample | Paraffin-embedded human colorectal adenocarcinoma tissue; fixative not specified (datasheet M00664-2) |
| Fixation | Image fixative and duration unreported (datasheet M00664-2); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: EDTA pH 8.0 (datasheet M00664-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet M00664-2) |
| Primary antibody | Mouse monoclonal (clone 5I13D1) anti-PVR, 2 μg/ml (datasheet M00664-2) |
| Primary incubation | Overnight at 4 °C (datasheet M00664-2) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet M00664-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | PVR-positive staining in cardiomyocytes of heart muscle (HPA tissue IHC: High). HPA tissue profile: Membrane and cytoplasmic expression in several tissues. Positivity in plasma. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval (datasheet: M00664-2); optimize locally because the chromogenic TMA report omits retrieval conditions (PMC9352965).
Section 2
What Is the Expected PVR Staining Pattern?
PVR is a membrane protein with an extracellular region at residues 21–343 and a cytoplasmic tail at 368–417; a secreted form is also annotated (UniProt P15151 topology; UniProt P15151 subcellular). In paraffin tissue sections, expect membrane and cytoplasmic staining in selected cells, especially cardiomyocytes and placental decidual cells (HPA tissue IHC: High). HPA rates the tissue pattern Approved, with medium consistency between staining and RNA expression (HPA tissue IHC reliability).
| Membrane and cytoplasmic staining in cardiomyocytes or placental decidual cells. | This matches the reported compartments and two High staining examples (HPA tissue IHC). Score the specified cells and compartments separately; intensity elsewhere need not match them because HPA reports Medium, Low and Not detected results in other cell types (HPA tissue IHC). |
| Staining confined to nuclei in an otherwise positive paraffin tissue section. | Nuclear-only tissue IHC is outside HPA's reported membrane and cytoplasmic tissue pattern (HPA tissue IHC). Review morphology, counterstain and controls before calling it PVR. Nucleoplasm is an approved ICC-IF location, which does not establish a nuclear tissue IHC pattern (HPA subcellular). |
| Strong staining in adipocytes or bone marrow hematopoietic cells. | These specific cells were Not detected in HPA tissue IHC (HPA tissue IHC). Check whether the signal follows the intended cells and compartments; cross-reactivity or endogenous detection activity is possible (general IHC practice). Do not infer that every cell in either tissue must be negative. |
| Uniform haze across cells and spaces, without a recognizable membrane or cellular pattern. | This is difficult to reconcile with HPA's cell-specific tissue pattern (HPA tissue IHC). Check the negative control and detection background (general IHC practice). Because HPA reports plasma positivity and UniProt annotates secretion, extracellular signal alone does not prove an artefact (HPA tissue IHC; UniProt P15151 subcellular). |
| No staining in cardiomyocytes or placental decidual cells. | These are High examples and useful positive comparators (HPA tissue IHC). If both sample and comparator are blank, first examine the shared IHC workflow (general IHC practice). A blank test section alone cannot distinguish a technical failure from a biological difference; HPA reliability is Approved with medium consistency (HPA tissue IHC reliability). |
💡Expected PVR appearanceCall positive tissue IHC when identifiable cardiomyocytes or placental decidual cells show High membrane and cytoplasmic staining (HPA tissue IHC); nuclear-only signal or uniform cell-independent haze warrants control review (HPA tissue IHC; general IHC practice).
| Membrane topology and epitope location | PVR has extracellular residues 21–343, a transmembrane segment at 344–367 and a cytoplasmic tail at 368–417 (UniProt P15151 topology). The supplied record does not map an antibody epitope, so topology cannot predict which compartment an individual antibody will favor in a section. |
| Secreted form and plasma staining | UniProt annotates PVR as secreted as well as membrane-localized (UniProt P15151 subcellular). HPA reports positivity in plasma and cautions that at least one secreted variant can complicate RNA–protein comparisons (HPA tissue IHC). Interpret extracellular color with cellular morphology and controls. |
| Isoforms and processing | Four isoforms—Alpha, Beta, Gamma and Delta—are listed, and a signal peptide spans residues 1–20 (UniProt P15151 isoforms; UniProt P15151 processing). Without an epitope map or isoform-specific IHC evidence, do not assign a staining pattern to one isoform or assume how processing affects detection. |
| Retrieval and detection conditions | For paraffin IHC, check that antigen retrieval, blocking, primary antibody dilution, chromogenic detection and counterstain follow the selected validated workflow (general IHC practice). Neither HPA tissue levels nor UniProt topology establishes a PVR-specific retrieval requirement or fixation sensitivity. |
| IF/ICC Q&A: should the same compartments appear? | HPA ICC-IF lists nucleoplasm and vesicles as approved locations and plasma membrane as supported (HPA subcellular). Tissue IHC instead reports membrane and cytoplasmic expression (HPA tissue IHC). Interpret each application against its own evidence; the supplied ICC-IF record provides no IF protocol option. |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected positive tissue is blank. | A missing primary or detection step, ineffective retrieval, or an unsuitable working dilution may suppress chromogenic signal (general IHC practice). | Run a positive comparator containing cardiomyocytes or placental decidual cells, both High in HPA tissue IHC (HPA tissue IHC); verify each workflow step and the chosen antibody's own IHC instructions (general IHC practice). |
| Most of the section shows diffuse brown background. | Nonspecific binding or detection background may obscure cellular staining (general IHC practice). HPA's plasma positivity means some extracellular signal may also be biological (HPA tissue IHC). | Inspect a negative control, check blocking and detection steps, and judge signal against recognizable cells and compartments (general IHC practice); do not score diffuse color alone as PVR. |
| Nuclei dominate the tissue IHC image. | The signal does not match HPA's tissue membrane and cytoplasmic profile (HPA tissue IHC); the approved nucleoplasmic location comes from ICC-IF (HPA subcellular). | Confirm section morphology and counterstain, compare the negative control, and seek membrane or cytoplasmic staining in a High comparator before assigning tissue IHC positivity (HPA tissue IHC; general IHC practice). |
| Unexpected cells stain strongly. | Cell-specific differences are possible, but signal in HPA Not detected adipocytes or bone marrow hematopoietic cells also raises possible cross-reactivity or endogenous detection activity (HPA tissue IHC; general IHC practice). | Identify the stained cell type, compare a negative control, and check whether staining has a credible membrane or cytoplasmic distribution (HPA tissue IHC; general IHC practice). |
| Only extracellular material stains. | A secreted form and plasma positivity could contribute (UniProt P15151 subcellular; HPA tissue IHC); nonspecific detection remains another possibility (general IHC practice). | Compare extracellular signal with the negative control and with staining in identifiable positive cells (general IHC practice; HPA tissue IHC). Report the observed compartment rather than treating extracellular color as proof of cell-surface PVR. |
| A tissue or cell type stains less than expected from RNA data. | HPA reports low tissue RNA specificity, while its antibody staining has medium consistency with RNA; a secreted variant can place protein and RNA in different locations (HPA tissue IHC reliability; HPA tissue IHC RNA specificity). | Base the IHC interpretation on the observed cell type, compartment and controls (general IHC practice). Use HPA's cell-specific protein examples as comparators rather than requiring RNA abundance to predict staining intensity (HPA tissue IHC). |
Experiment evidence
IHC & IF images showing PVR staining
M00664-2 · IHCIHC analysis of Poliovirus Receptor/PVR using anti-Poliovirus Receptor/PVR antibody (M00664-2). Poliovirus Receptor/PVR was detected in a pa
M00664-2 · IHCIHC analysis of Poliovirus Receptor/PVR using anti-Poliovirus Receptor/PVR antibody (M00664-2). Poliovirus Receptor/PVR was detected in a pa
M00664-1 · IHCIHC analysis of Poliovirus Receptor/PVR using anti-Poliovirus Receptor/PVR antibody (M00664-1). Poliovirus Receptor/PVR was detected in a pa
M00664-1 · IHCIHC analysis of Poliovirus Receptor/PVR using anti-Poliovirus Receptor/PVR antibody (M00664-1). Poliovirus Receptor/PVR was detected in a pa
A00664-2 · IHCIHC analysis of Poliovirus Receptor/PVR using anti-Poliovirus Receptor/PVR antibody (A00664-2). Poliovirus Receptor/PVR was detected in para
A00664-2 · IHCIHC analysis of Poliovirus Receptor/PVR using anti-Poliovirus Receptor/PVR antibody (A00664-2). Poliovirus Receptor/PVR was detected in para
A00664-2 · IFIF analysis of Poliovirus Receptor/PVR using anti-Poliovirus Receptor/PVR antibody (A00664-2). Poliovirus Receptor/PVR was detected in immun
M00664-3 · IHCIHC analysis of Poliovirus Receptor/PVR using anti-Poliovirus Receptor/PVR antibody (M00664-3). Poliovirus Receptor/PVR was detected in a pa
M00664-3 · IHCIHC analysis of Poliovirus Receptor/PVR using anti-Poliovirus Receptor/PVR antibody (M00664-3). Poliovirus Receptor/PVR was detected in a pa
A00664-4 · IHCIHC analysis of Poliovirus Receptor/PVR using anti-Poliovirus Receptor/PVR antibody (A00664-4). Poliovirus Receptor/PVR was detected in a pa
A00664-4 · IFIF analysis of Poliovirus Receptor/PVR using anti-Poliovirus Receptor/PVR antibody (A00664-4). Poliovirus Receptor/PVR was detected in an im
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000073008-PVR/tissue/cerebral+cortex#imid_3327600
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000073008-PVR/tissue/colon#imid_3327526
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000073008-PVR/tissue/liver#imid_3327543
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000073008-PVR/tissue/kidney#imid_3327536
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA012568; green = PVR, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA012568; green = PVR, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for PVR IHC & IF
🧪Run placenta first: decidual cells must show PVR staining (HPA: High in decidual cells). Use adipose tissue as the negative comparator (HPA: Not detected in adipocytes); on the placenta slide, cells assessed as internal negatives should show only background-level chromogen, but their PVR status needs independent verification before scoring (standard IHC practice).
Positive control tissue: Heart muscle (Cardiomyocytes, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show PVR in A-431, U-251MG, U2OS, with annotated localisation: Nucleoplasm (approved), Vesicles (approved), Plasma membrane (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control; an isotype control matched to the primary antibody’s host species and clonality; and PVR-knockout material as a biological negative (standard IHC practice). Check for endogenous peroxidase signal and blood-associated background in placenta before interpreting DAB staining (standard IHC practice).
⚠️Feasibility: The selected M00664-2 paraffin-section caption reports heat retrieval in EDTA at pH 8.0, followed by primary antibody at 2 μg/ml overnight at 4°C (selected-SKU tissue-IHC caption). Its fixative is unreported, and the supplied evidence reports no PVR-specific fixation window or fixation effect (selected-SKU tissue-IHC caption). The caption demonstrates a paraffin IHC workflow, but the supplied evidence does not establish that frozen sections or IF/ICC are easier; assess placental blood-associated background when interpreting chromogenic signal (selected-SKU tissue-IHC caption; standard IHC practice).
HPA tissue IHC evidence for PVR
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Medium consistency between antibody staining and RNA expression data. At least one protein variant secreted, tissue location of RNA and protein might differ and correlation is complex.). 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 |
|---|---|---|---|---|
| Heart muscle | Cardiomyocytes | High | Protein (IHC) | HPA → |
| Placenta | Decidual cells | High | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Medium | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Medium | Protein (IHC) | HPA → |
| Caudate | Glial cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Bronchus | Basal cells | Not detected | Protein (IHC) | HPA → |
| Fallopian tube | Ciliated cells (cell body) | Not detected | Protein (IHC) | HPA → |
| Hippocampus | Glial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced PVR IHC Tips
Troubleshoot PVR staining in paraffin sections by checking retrieval, compartment, controls and scoring before interpreting chromogenic signal.
Which retrieval conditions should I start with when PVR staining is weak?
Start with heat mediated retrieval in EDTA at pH 8.0 (datasheet M00664-2). The catalog antibody stained a paraffin section of human colorectal adenocarcinoma after this retrieval, followed by 2 μg/ml primary antibody overnight at 4°C (datasheet M00664-2). If staining is weak, first verify that the section stayed immersed and that heating and cooling were consistent across slides; compare each change with a section processed using the reported conditions (standard IHC practice). Assess membrane and cytoplasmic signal separately, since both occur in tissue (HPA tissue IHC), and avoid judging retrieval from background alone.
Could fixation explain weak or uneven PVR staining?
The selected paraffin tissue caption does not report a fixative, so target specific sensitivity to fixation is unknown (datasheet M00664-2). Record the fixative, fixation duration and tissue thickness for each specimen, then compare matched sections processed with the same pH 8.0 EDTA retrieval and antibody concentration (datasheet M00664-2; standard IHC practice). Uneven penetration or variable processing can produce uneven staining in paraffin sections (standard IHC practice), but that pattern alone does not establish a PVR specific fixation effect. Include a consistently positive reference section with each run and assess staining within viable tissue before changing the primary antibody conditions (standard IHC practice).
How should I evaluate membrane, cytoplasmic and nuclear PVR staining?
Score membrane and cytoplasmic staining separately because both are reported in tissues (HPA tissue IHC). PVR has an extracellular region at residues 21–343, a transmembrane segment at 344–367 and a cytoplasmic region at 368–417 (UniProt P15151 topology). Secreted PVR is also annotated, and positivity in plasma can complicate attribution of diffuse extracellular signal to cells (UniProt P15151 subcellular; HPA tissue IHC). Nucleoplasm and vesicles appear in the subcellular IF record (HPA subcellular), so investigate nuclear IHC signal with compartment specific controls and a second validated antibody before assigning it to a particular PVR form (standard IHC practice).
Can one IHC antibody distinguish PVR isoforms or extracellular from intracellular epitopes?
PVR has 4 annotated isoforms: Alpha, Beta, Gamma and Delta (UniProt P15151 isoforms). Its extracellular Ig like domains span residues 24–328, whereas the cytoplasmic region spans 368–417 (UniProt P15151 domains and topology). The supplied tissue caption does not identify the antibody epitope or establish isoform specificity, so a positive chromogenic stain cannot by itself assign an isoform (datasheet M00664-2). Check a documented immunogen or epitope against isoform sequences before making that claim; when comparing antibodies, use matched sections and report whether each yields membrane, cytoplasmic or extracellular staining (standard IHC practice; HPA tissue IHC).
How can I investigate PVR localisation with multiplex IF?
Use IF as a separate localisation check and pair PVR with a marker that identifies the cell type being evaluated (standard IF practice). Select spectrally separated fluorophores after examining unstained tissue for autofluorescence, and include single colour controls when testing overlap (standard IF practice). If the antibody recognises the extracellular region at residues 21–343, compare surface staining without permeabilisation; access to a cytoplasmic epitope at 368–417 requires permeabilisation (UniProt P15151 topology; standard IF practice). Interpret nucleoplasmic, vesicular and plasma membrane patterns in light of the subcellular IF record, while keeping IF observations distinct from chromogenic tissue IHC scoring (HPA subcellular).
What should I check when PVR DAB staining is diffuse or widespread?
Compare a primary antibody omission control with a matched stained section to identify signal from the detection system (standard IHC practice). The reported tissue procedure used 10% goat serum blocking, a peroxidase conjugated secondary antibody and DAB development (datasheet M00664-2). Peroxidase blocking and careful DAB timing are general chromogenic IHC controls, particularly when diffuse colour obscures cell boundaries (standard IHC practice). Distinguish extracellular or plasma associated positivity from cellular membrane staining because a secreted PVR variant is annotated and plasma positivity is reported (UniProt P15151 subcellular; HPA tissue IHC). If background persists, check reagent only controls and section edges before changing antibody concentration (standard IHC practice).
How should I score heterogeneous PVR staining across a tissue section? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring, since tissue IHC reports both membrane and cytoplasmic PVR expression (HPA tissue IHC). For a cell based score, record the percentage of viable target cells at intensity 0–3 and calculate an H score on a 0–300 scale, or report percent positive cells with a stated threshold (standard IHC practice). For spatial counts, report positive cells per mm² of viable tissue and normalise comparisons to the same sampled area or target cell population (standard IHC practice). Keep extracellular staining separate from cellular scores because secreted variants and plasma positivity can complicate assignment (UniProt P15151 subcellular; HPA tissue IHC).
How do I distinguish genuine PVR staining from tissue artefacts?
Look for reproducible signal in the expected cells and record membrane, cytoplasmic and extracellular patterns separately (HPA tissue IHC; standard IHC practice). A positive membrane pattern is consistent with PVR topology, while diffuse extracellular staining needs caution because secreted PVR and plasma positivity are reported (UniProt P15151 topology and subcellular; HPA tissue IHC). Compare viable areas with section edges and necrotic regions, where processing artefacts can distort chromogenic signal (standard IHC practice). Use a primary antibody omission control to assess endogenous enzyme or detection background, and compare a reference section across runs before treating an unusual compartment or cell population as PVR positive (standard IHC practice).
Boster reagents
Best PVR / Poliovirus receptor IHC Antibodies
The catalog shows paraffin-section IHC images for human colorectal adenocarcinoma and liver cancer, plus mouse liver cancer (catalog IHC captions); IF/ICC images cover A431 and SiHa cells (catalog IF captions).
Real IHC data
Anti-Poliovirus Receptor/PVR Antibody ® (monoclonal, 5I13D1)
Cat # M00664-2
Real IHC data
Anti-Poliovirus Receptor/PVR Antibody ® (monoclonal, 9B9F1)
Cat # M00664-1
Real IHC data
Anti-Poliovirus Receptor/PVR Antibody ®
Cat # A00664-2
Real IHC data
Anti-Poliovirus Receptor/PVR Antibody ® (monoclonal, 3B11E9)
Cat # M00664-3
Real IHC data
Anti-Poliovirus Receptor/PVR Antibody ®
Cat # A00664-4
M00664-2 and M00664-1 each have human colorectal adenocarcinoma paraffin-section IHC images; M00664-3 has human and mouse liver cancer paraffin-section IHC images (each SKU’s IHC captions). A00664-2 and A00664-4 each have human liver cancer paraffin-section IHC images, with IF/ICC images in A431 and SiHa cells, respectively (each SKU’s IHC and IF captions).
Which to pick: For human tissue IHC, choose among the five SKUs by the tissue shown in each SKU’s own paraffin-section caption; each caption reports EDTA retrieval at pH 8.0, but does not report the fixative (catalog IHC captions). For IF/ICC, choose A00664-2 for A431 cells or A00664-4 for SiHa cells; both are rabbit antibodies listed for IF and ICC (catalog applications and IF captions). For human and mouse tissue IHC, consider mouse monoclonal M00664-3 first because its own captions show IHC in both species; M00664-1 and M00664-2 also list human and mouse reactivity, while their shown IHC images are human (catalog reactivity, clone fields and IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P15151 (PVR_HUMAN, Poliovirus receptor).
- Human Protein Atlas. PVR tissue IHC expression (reliability: Approved).
- Human Protein Atlas. PVR subcellular location (ICC-IF): Localized to the nucleoplasm, plasma membrane and vesicles..
- Human Protein Atlas. PVR antibody validation summary (2 antibodies).
- TIGIT agonism as a therapeutic strategy to suppress inflammation in hidradenitis suppurativa. Frontiers in immunology 2026 — PMC13079107.
- Epithelial CD155-TIGIT/CD226 signaling links CD8⁺ T-cell exhaustion to frequent exacerbations in COPD. Respiratory research 2026 — PMC13195874.
- Effect of Methotrexate on an In Vitro Patient-Derived Model of Proliferative Vitreoretinopathy. Investigative ophthalmology & visual science 2017 — PMC5544356.
- PVR/TIGIT and PD-L1/PD-1 expression predicts survival and enlightens combined immunotherapy in lung squamous cell carcinoma. Translational oncology 2022 — PMC9352965.
- PubMed PMID:2538245 — UniProt-cited evidence.
- PubMed PMID:2170108 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for PVR (Poliovirus receptor). Expected localisation Membrane and cytoplasmic staining in several tissues (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet M00664-2). Validated IHC antibody: M00664-2 at 2 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Heart muscle (Cardiomyocytes); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human colorectal adenocarcinoma tissue; fixative not specified (datasheet M00664-2); 2. Fixation: Image fixative and duration unreported (datasheet M00664-2); 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: EDTA pH 8.0 (datasheet M00664-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet M00664-2); 8. Primary antibody: Mouse monoclonal (clone 5I13D1) anti-PVR, 2 μg/ml (datasheet M00664-2); 9. Primary incubation: Overnight at 4 °C (datasheet M00664-2). Watch for: Fixation: Keep fixation consistent across sections. (standard IHC practice; not target-specific); Caveat: Secreted variants may complicate tissue staining (HPA tissue IHC); Isoform / epitope: 4 isoforms; check extracellular vs cytoplasmic epitope (UniProt); Regulation: No specific regulator annotated (UniProt). Evidence: UniProt P15151, HPA tissue IHC · Approved, HPA ICC-IF · nucleoplasm, plasma membrane and vesicles., Datasheet M00664-2, PMC9352965. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/PVR/immunohistochemistry-ihc-guide.