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S100A7 / Protein S100-A7 · IHC design guide
Design Immunohistochemistry for S100A7
Plan S100A7 staining in paraffin sections using skin corneal-layer cells as a high-staining reference (HPA tissue IHC). The guide covers the catalog antibody’s 0.5–1 μg/mL IHC range (datasheet A02369-1) and interpretation of squamous epithelial staining (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
S100A7 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 | Cytoplasmic or secreted; tissue compartment unresolved (UniProt) | |
| Staining pattern | Squamous epithelial staining; subcellular pattern unreported (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6 HIER, heat-mediated (datasheet A02369-1) | |
| Positive control | Skin+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 tissue fixation consistent across sections (standard IHC practice; not target-specific) | |
| Caveat | Secretion may separate protein staining from its source cells (HPA tissue IHC) | |
| Regulation | Up-regulated in psoriatic epidermis (UniProt) | |
| Isoform / epitope | No isoforms; chain 2–101; no distinct secreted epitope mapped (UniProt) |
Section 1
Recommended S100A7 IHC & IF Protocols
The catalog antibody's IHC-P protocol is accompanied by three published S100A7 tissue-staining protocols (PMC11732109; PMC12031700; PMC2914786).
| Sample | Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet A02369-1) |
| Fixation | Image fixative and duration unreported (datasheet A02369-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Citrate pH 6, 20 min (datasheet A02369-1) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A02369-1) |
| Primary antibody | Rabbit anti-S100A7, 0.5-1μg/ml (datasheet A02369-1) |
| Primary incubation | Overnight at 4 °C (datasheet A02369-1) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A02369-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | S100A7-positive staining in cells in corneal layer of skin (HPA tissue IHC: High). HPA tissue profile: Expression in squamous epithelia. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated citrate pH 6 retrieval for the catalog antibody (datasheet: A02369-1); a published oral-tissue protocol also uses citrate pH 6 (PMC2914786).
Section 2
What Is the Expected S100A7 Staining Pattern?
S100A7 is cytoplasmic and can be secreted; it has no transmembrane segment (UniProt P31151). In tissue IHC, expect staining chiefly in squamous epithelia, with high staining in skin corneal-layer cells and medium staining in several other epithelial sites (HPA tissue IHC). HPA rates the tissue profile Enhanced but cautions that its antibodies can target proteins from more than one gene (HPA tissue IHC).
| Skin corneal-layer cells stain strongly; squamous epithelial cells in cervix, esophagus, oral mucosa, tonsil, or vagina stain less strongly (HPA tissue IHC). | This matches HPA's high skin and medium squamous-epithelial observations (HPA tissue IHC). Judge intensity within the relevant cell layer and alongside a negative control; a darker chromogen deposit alone does not establish that every stained cell is S100A7-positive (standard IHC practice; HPA tissue IHC cross-gene caution). |
| Staining is predominantly nuclear or traces cell borders while cytoplasm is clear. | That compartment disagrees with UniProt's cytoplasmic annotation and HPA's supported cytosolic ICC-IF location (UniProt P31151; HPA subcellular ICC-IF). Review the negative control, morphology, and detection conditions before interpreting it as target staining (standard IHC practice). Extracellular signal needs separate caution because S100A7 can be secreted (UniProt P31151). |
| Adipocytes in adipose tissue or hematopoietic cells in bone marrow stain as strongly as the positive epithelial layer. | HPA reports those cell populations as not detected in tissue IHC (HPA tissue IHC). Staining there raises concern about nonspecific antibody binding or endogenous detection activity (standard IHC practice). It cannot, by itself, identify which mechanism occurred; compare the matching negative control and the known-positive tissue on the same run (standard IHC practice). |
| Chromogen covers much of the section, including empty spaces or cells expected to be negative. | Widespread deposit obscures the cell-restricted pattern reported for S100A7 (HPA tissue IHC). Check background in the negative control and whether blocking, washing, antibody concentration, or chromogen development contributed (standard IHC practice). Do not score diffuse deposit as expression solely because some expected epithelial cells also appear stained (standard IHC practice). |
| No convincing stain appears in skin corneal-layer cells or another selected known-positive epithelium. | That result conflicts with the selected HPA-positive reference: skin corneal-layer staining is high, while several squamous epithelial sites are medium (HPA tissue IHC). First establish that the reference layer is present and the run controls worked; then review retrieval and detection settings as general IHC variables (standard IHC practice). The supplied sources do not establish S100A7-specific fixation sensitivity. |
💡Expected S100A7 appearanceCall a positive result when the relevant epithelial cells show a discernible cytoplasmic pattern, strongest in skin corneal-layer cells (UniProt P31151; HPA tissue IHC); broad staining of HPA-negative cells or section-wide deposit is suspect (HPA tissue IHC; standard IHC practice).
| Cell and tissue context (HPA tissue IHC) | HPA reports high staining in skin corneal-layer cells and medium staining in several squamous epithelial populations; its listed negative cell populations offer comparison fields (HPA tissue IHC). Compare the named cell type, rather than calling an entire tissue uniformly positive or negative (standard IHC practice). |
| Compartment and secretion (UniProt P31151; HPA subcellular ICC-IF) | Cytoplasmic localisation is annotated by UniProt, and cytosol is supported in HPA ICC-IF (UniProt P31151; HPA subcellular ICC-IF). UniProt also records non-classical secretion, so extracellular material may complicate assigning a stained deposit to its cell of origin (UniProt P31151). |
| Antibody evidence and specificity (HPA tissue IHC; HPA antibodies) | The tissue profile is rated Enhanced, yet HPA warns that antibodies may target proteins from more than one gene (HPA tissue IHC). HPA lists CAB001453 and CAB033766 as IHC Enhanced, and HPA006997 as IHC Supported (HPA antibodies). Interpret unexpected cell staining with that specificity limit in mind. |
| Molecular features (UniProt P31151) | UniProt reports one 2–101 chain, no signal peptide, no annotated isoforms, and no glycosylation sites (UniProt P31151). These facts do not identify this antibody's epitope or establish a preferred antigen-retrieval condition; choose and assess retrieval using the assay's validated IHC conditions (standard IHC practice). |
| IF/ICC Q: What compartment should appear? (HPA subcellular ICC-IF) | A: HPA supports a cytosolic location in ICC-IF, with a caution that the antibodies target proteins from multiple genes (HPA subcellular ICC-IF). Use that location as an interpretation check for IF/ICC; this IHC section supplies no IF/ICC protocol. |
| Situation | Likely cause | Next action |
|---|---|---|
| Known-positive corneal-layer cells are unstained (HPA tissue IHC). | The sampled layer may be absent, or an IHC processing or detection step may have failed (standard IHC practice). | Confirm the layer on the counterstained section, check run controls, then review the validated retrieval and detection settings (standard IHC practice). |
| Expected epithelial staining is faint compared with the HPA pattern (HPA tissue IHC). | The chosen site may have medium rather than high reported staining, or assay conditions may reduce visible contrast (HPA tissue IHC; standard IHC practice). | Compare the same cell type in a known-positive section and check antibody dilution and development against the validated IHC setup (standard IHC practice). |
| Nuclei or cell borders dominate the signal. | The pattern conflicts with cytoplasmic or cytosolic localisation; background or localisation misassignment is possible (UniProt P31151; HPA subcellular ICC-IF; standard IHC practice). | Inspect morphology and negative controls, then reassess staining conditions before scoring those compartments as positive (standard IHC practice). |
| HPA-listed negative cells stain, including adipocytes or bone-marrow hematopoietic cells (HPA tissue IHC). | Nonspecific binding or endogenous detection activity can mimic a positive chromogenic result (standard IHC practice). | Compare a matched negative control, review blocking and detection, and check whether the expected positive epithelium retains its cell-restricted pattern (standard IHC practice; HPA tissue IHC). |
| Diffuse chromogen obscures epithelial boundaries. | Excess background from assay conditions can prevent cell-level interpretation (standard IHC practice). | Inspect negative-control deposit; review blocking, washes, antibody concentration, and chromogen development before scoring (standard IHC practice). |
| Two antibodies give different cell patterns (HPA antibodies). | HPA's cross-gene warning limits assignment of every stained cell to S100A7 (HPA tissue IHC). | Prioritise agreement with the documented tissue and cytosolic patterns, and report the disagreement with each antibody's HPA validation status (HPA tissue IHC; HPA subcellular ICC-IF; HPA antibodies). |
Experiment evidence
IHC & IF images showing S100A7 staining
A02369-1 · IHCIHC analysis of Psoriasin using anti-Psoriasin antibody (A02369-1). Psoriasin was detected in paraffin-embedded section of human lung cancer
A02369-1 · IHCIHC analysis of Psoriasin using anti-Psoriasin antibody (A02369-1). Psoriasin was detected in paraffin-embedded section of human rectal canc
A02369-1 · IFIF analysis of Psoriasin using anti-Psoriasin antibody (A02369-1). Psoriasin was detected in immunocytochemical section of A431 cells. Enzym
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000143556-S100A7/tissue/cerebral+cortex#imid_12288579
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000143556-S100A7/tissue/colon#imid_12288486
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000143556-S100A7/tissue/liver#imid_12288495
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000143556-S100A7/tissue/kidney#imid_12288488
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA006997; green = S100A7, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA006997; green = S100A7, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for S100A7 IHC & IF
🧪Run skin first: cells in the corneal layer should stain (HPA: High in skin corneal-layer cells); use adipose tissue as the negative tissue, focusing on adipocytes (HPA: Not detected in adipocytes). On the skin slide, non-corneal cells without staining can serve as internal background comparators; the supplied HPA row does not establish that all non-corneal skin cells are negative (HPA: skin corneal-layer row).
Positive control tissue: Skin (Cells in corneal layer, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show S100A7 in A-431, U2OS, with annotated localisation: Cytosol (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control and a rabbit IgG isotype control matched to the primary antibody’s clonality where known (selected-SKU caption: rabbit primary; standard IHC practice); confirm target specificity with S100A7-knockout material or an immunizing-peptide block if available (standard IHC practice). For the skin positive control, assess endogenous peroxidase and biotin background before interpreting DAB staining from the biotin-based detection system (selected-SKU caption: biotinylated secondary, SABC and DAB; standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected-SKU paraffin-section caption does not state a fixative (selected-SKU caption: fixative unreported). That caption uses heat retrieval in citrate buffer at pH 6 for 20 minutes, but whether staining depends on retrieval is unreported (selected-SKU caption). The supplied evidence does not establish that frozen sections or IF are easier; in skin, inspect the corneal layer for nonspecific surface staining when scoring the expected signal (HPA: High in corneal-layer cells; standard IHC practice).
HPA tissue IHC evidence for S100A7
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Medium consistency between antibody staining and RNA expression data. Caution, targets protein from more than one gene. 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 |
|---|---|---|---|---|
| Skin | Cells in corneal layer | High | Protein (IHC) | HPA → |
| Cervix | Squamous epithelial cells | Medium | Protein (IHC) | HPA → |
| Epididymis | Glandular cells | Medium | Protein (IHC) | HPA → |
| Esophagus | Squamous epithelial cells | Medium | Protein (IHC) | HPA → |
| Nasopharynx | Respiratory epithelial cells | Medium | 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 S100A7 IHC Tips
Troubleshoot S100A7 staining by checking tissue context, cytoplasmic localisation and the limits of the catalog antibody’s paraffin-section evidence.
What retrieval should I try when S100A7 staining is weak in paraffin sections?
Start with heat-mediated citrate retrieval at pH 6 for 20 minutes (datasheet A02369-1). The catalog antibody’s paraffin-section image used that condition before overnight incubation at 4°C with 1 µg/ml primary antibody (datasheet A02369-1). If signal remains weak, compare a modestly longer retrieval time on adjacent sections while keeping antibody concentration and detection constant (standard IHC practice). Include a skin section containing corneal-layer cells as a positive control, because these cells show high S100A7 staining (HPA: Skin, cells in corneal layer, High). Check tissue preservation and background before attributing absent staining to retrieval alone (standard IHC practice).
Could fixation explain inconsistent S100A7 staining across my sections?
Target-specific fixation sensitivity is unknown from the supplied evidence; the catalog image identifies a paraffin section but does not state its fixative (datasheet A02369-1). Record each specimen’s fixative and fixation time, then compare sections processed and stained together with the same citrate pH 6 retrieval (standard IHC practice; datasheet A02369-1). Include a positive-control section with high staining in skin corneal-layer cells to distinguish a failed staining run from a specimen-specific result (HPA: Skin, cells in corneal layer, High). Do not infer a fixation effect from S100A7’s cytoplasmic and secreted locations or its annotated acetylation (UniProt P31151 localisation and modified residues).
Should I score S100A7 staining outside epithelial cell cytoplasm?
Assess epithelial cytoplasmic staining first: S100A7 is annotated as cytoplasmic and secreted, with no transmembrane segment, while the subcellular atlas supports a cytosolic location (UniProt P31151 localisation and topology; HPA: subcellular summary). Squamous epithelia provide a tissue context, with medium staining reported in cervical and esophageal squamous epithelial cells (HPA: tissue profile and positive tissues). Extracellular signal may warrant review because secretion uses a non-classical pathway, but it should not automatically be counted as positive cells (UniProt P31151 localisation; standard IHC practice). Compare the signal with cell boundaries and a matched control section before assigning unusual nuclear or membrane staining to S100A7 (standard IHC practice).
How can epitope uncertainty affect interpretation of S100A7 IHC?
The record lists 0 isoforms and two EF-hand regions at residues 13–48 and 50–85, but it does not map this antibody’s epitope (UniProt P31151 isoforms and domains; datasheet A02369-1). Therefore, an absent stain cannot be assigned to loss of a particular isoform or EF-hand epitope from these data (UniProt P31151 isoforms and domains; standard IHC interpretation). The atlas cautions that its tissue staining targets protein from more than one gene, limiting gene-specific conclusions from concordant patterns (HPA: tissue reliability description). Compare antibody staining with an independent, appropriately validated assay when the distinction between S100A7 and related proteins changes the conclusion (standard IHC practice).
How should I check S100A7 localisation by IF alongside chromogenic IHC?
Use the separate IF/ICC workflow to check whether fluorescence occupies cytosol in cells corresponding to the epithelial population scored by IHC (HPA: supported cytosol location and squamous-epithelium tissue profile). Multiplex with a validated marker for the expected epithelial cell type, and choose a spectrally separated, preferably far-red fluorophore after checking tissue autofluorescence in an unstained section (standard IF practice). Because S100A7 is cytoplasmic and has no transmembrane segment, permeabilisation may help expose a cytosolic epitope; the catalog antibody’s epitope is not mapped here (UniProt P31151 localisation and topology; datasheet A02369-1). Compare compartment and cell identity across methods without transferring the paraffin-section retrieval or incubation conditions to IF (datasheet A02369-1; standard IF practice).
What should I check if DAB obscures S100A7-positive cells?
The catalog image used 10% goat serum blocking, a biotinylated secondary antibody, a streptavidin–biotin complex and DAB detection (datasheet A02369-1). When diffuse brown signal obscures cells, inspect a no-primary control and evaluate endogenous peroxidase and biotin background in the tissue before changing primary-antibody concentration (standard IHC practice). Compare a shorter DAB development with the original condition on adjacent sections so that weak epithelial signal remains visible (standard IHC practice). Keep high-staining skin corneal-layer cells and an unstained control in the run; this helps distinguish background from the expected S100A7-positive compartment (HPA: Skin, cells in corneal layer, High; standard IHC practice).
How should I quantify heterogeneous S100A7 staining in paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the epithelial region of interest before scoring, because the atlas describes S100A7 expression in squamous epithelia and reports high staining in skin corneal-layer cells (HPA: tissue profile and Skin positive tissue). Record the percentage of positive epithelial cells and staining intensity, then calculate an H-score using consistent intensity bins and thresholds across sections (standard IHC practice). Normalise cell counts to the number of evaluable epithelial cells, or report positive area per mm² of evaluable epithelium when boundaries are reliable (standard IHC practice). Exclude folds, necrosis and section edges by a prespecified rule, and report extracellular staining separately from cell-based scores (standard IHC practice; UniProt P31151 localisation).
When is unexpected S100A7 staining likely to be artefactual?
A credible positive result should have interpretable cellular staining in a plausible tissue context, such as squamous epithelium, with cytoplasm as the principal compartment (HPA: tissue profile and supported cytosol location). Review isolated nuclear or sharply outlined membrane signal against controls, since S100A7 has no transmembrane segment and the supplied localisation evidence supports cytoplasm and secretion (UniProt P31151 topology and localisation; HPA: subcellular summary). Edge accentuation, necrotic debris or staining reproduced in a no-primary control points toward a technical explanation, including endogenous enzyme activity in a DAB workflow (standard IHC practice). Because atlas antibodies can detect proteins from more than one gene, staining pattern alone does not establish S100A7 specificity (HPA: tissue reliability description).
Boster reagents
Best S100A7 / Protein S100-A7 IHC Antibodies
A02369-1 has IHC images from paraffin-embedded human lung and rectal cancer sections and an IF/ICC image from A431 cells (catalog image captions). Listed reactivity includes human, mouse, and rat (catalog).
Real IHC data
Anti-Psoriasin/S100A7 Antibody ®
Cat # A02369-1
A02369-1 will render with its own IHC figure from a paraffin-embedded human lung cancer section (card image caption). Its catalog also documents IHC in a paraffin-embedded human rectal cancer section and IF/ICC in A431 cells (catalog image captions).
Which to pick: For tissue IHC, choose A02369-1: its IHC captions document paraffin sections, citrate pH 6 retrieval, and a 1 μg/ml primary antibody concentration (catalog IHC captions); the fixative is unreported (catalog IHC captions). For IF/ICC, the same SKU is listed for both applications and has an A431 cell image at 2 μg/ml (catalog applications; IF caption). For mouse or rat samples, A02369-1 lists reactivity with both species, while its supplied tissue IHC images use human samples (catalog reactivity; IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P31151 (S10A7_HUMAN, Protein S100-A7).
- Human Protein Atlas. S100A7 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. S100A7 subcellular location (ICC-IF): Localized to the cytosol. Caution: Based on antibodies targeting proteins from multiple genes..
- Human Protein Atlas. S100A7 antibody validation summary (3 antibodies).
- Compensatory effect-based oxidative stress management microneedle for psoriasis treatment. Bioactive materials 2025 — PMC11732109.
- S100A7 as a predictive biomarker in malignant transformation of oral epithelial dysplastic lesions. Discover oncology 2025 — PMC12031700.
- The Characteristics and Function of S100A7 Induction in Squamous Cell Carcinoma: Heterogeneity, Promotion of Cell Proliferation and Suppression of Differentiation. PloS one 2015 — PMC4460013.
- Nuclear S100A7 is associated with poor prognosis in head and neck cancer. PloS one 2010 — PMC2914786.
- PubMed PMID:1940442 — UniProt-cited evidence.
- PubMed PMID:16710414 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for S100A7 (Protein S100-A7). Expected localisation Cytoplasmic or secreted; tissue compartment unresolved (UniProt). Antigen retrieval: Citrate pH 6 HIER, heat-mediated (datasheet A02369-1). Validated IHC antibody: A02369-1 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Skin (Cells in corneal layer); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet A02369-1); 2. Fixation: Image fixative and duration unreported (datasheet A02369-1); 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: Citrate pH 6 , 20 min (datasheet A02369-1); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A02369-1); 8. Primary antibody: Rabbit anti-S100A7, 0.5-1μg/ml (datasheet A02369-1); 9. Primary incubation: Overnight at 4 °C (datasheet A02369-1). Watch for: Fixation: Keep tissue fixation consistent across sections (standard IHC practice; not target-specific); Caveat: Secretion may separate protein staining from its source cells (HPA tissue IHC); Isoform / epitope: No isoforms; chain 2–101 ; no distinct secreted epitope mapped (UniProt); Regulation: Up-regulated in psoriatic epidermis (UniProt). Evidence: UniProt P31151, HPA tissue IHC · Enhanced, HPA ICC-IF · cytosol. Caution: Based on antibodies targeting proteins from…, Datasheet A02369-1, PMC11732109, PMC12031700. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/S100A7/immunohistochemistry-ihc-guide.