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S100P / Protein S100-P · IHC design guide
Design Immunohistochemistry for S100P
Plan S100P IHC in paraffin sections using the cytoplasmic and nuclear tissue pattern reported in marrow, placenta and glandular epithelia (HPA tissue IHC). Compare staining across sections with consistent fixation, and interpret intensity in light of reported up-regulation in pancreatic ductal neoplasia (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
S100P 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 and nuclear staining (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic/nuclear in marrow, placenta and glandular epithelia (HPA tissue IHC) | |
| Antigen retrieval | Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen) | |
| Positive control | Bone marrow+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 | Staining consistency with RNA is medium; restaining is pending (HPA tissue IHC) | |
| Regulation | Up-regulated in pancreatic ductal neoplasia (UniProt) | |
| Isoform / epitope | No annotated isoforms or processing; one 1–95 chain (UniProt) |
Section 1
Recommended S100P IHC & IF Protocols
Compare the catalog antibody's IHC-P protocol with four published S100P IHC protocols covering pancreatic, multiple human tissue, hepatolithiasis, and nasopharyngeal specimens (PMC12743368; PMC2254630; PMC8046297; PMC5494647).
| Sample | Paraffin-embedded human bladder carcinoma tissue; fixative not specified (datasheet M01963) |
| Fixation | Image fixative and duration unreported (datasheet M01963); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat-induced epitope retrieval in Tris-EDTA buffer, pH 9.0, 20 min at 95–98 °C (standard rule: nuclear antigen) |
| 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 monoclonal (clone AOCH-19) anti-S100P, 1:50 (datasheet M01963) |
| 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 | S100P-positive staining in hematopoietic cells of bone marrow (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic and nuclear expression mainly in bone marrow, placenta and glandular epithelia in several tissues, including stomach and urinary bladder. No signal in the no-primary control. |
💡Decision noteStart with Tris-EDTA HIER at pH 9.0, 95–98 °C for 20 min (page retrieval); compare citrate at pH 6 if needed (PMC8046297).
Section 2
What Is the Expected S100P Staining Pattern?
S100P should appear in the cytoplasm and nuclei of selected cells, especially bone marrow hematopoietic cells, placental syncytiotrophoblasts, and stomach glandular cells (HPA: tissue IHC profile; High in each). HPA rates the tissue pattern Enhanced, while noting medium consistency with RNA data and pending restaining (HPA: reliability). S100P has no transmembrane segment, so a membrane-only pattern is unexpected (UniProt P25815: topology).
| Cytoplasmic and nuclear staining in the expected cells. | This matches the reported tissue pattern (HPA: tissue IHC profile). Strong staining is especially plausible in bone marrow hematopoietic cells, placental syncytiotrophoblasts, stomach glandular cells, and bladder urothelial cells (HPA: High in each). Compare cells within the section rather than assuming every cell should stain equally (HPA: cell-specific levels). |
| Predominantly membrane-only staining or signal confined to an unexpected compartment. | Recheck the result before scoring it as S100P: tissue IHC reports cytoplasmic and nuclear expression (HPA: tissue IHC profile), and the protein has no transmembrane segment (UniProt P25815: topology). UniProt also lists microvillus membrane localization, so focal projection-associated signal cannot be dismissed solely because it approaches a membrane (UniProt P25815: subcellular location). |
| Strong staining in a cell type reported as undetected. | For example, adipocytes or adrenal glandular cells are listed as Not detected (HPA: tissue IHC). Check the cell identification and controls; cross-reactivity or endogenous detection activity is possible (standard IHC practice). An HPA negative applies to the listed cell type and sampled context, not automatically to every cell in that organ. |
| Diffuse color over tissue, stroma, or an empty area, with little cell definition. | The distribution is difficult to reconcile with the reported cell-associated cytoplasmic and nuclear pattern (HPA: tissue IHC profile). Assess background in a matched negative control and review blocking, washes, and detection reagents (standard IHC practice). Do not use diffuse color alone to assign a positive S100P score. |
| No staining in a section containing a listed high-expression cell type. | First verify that the expected cells are present: HPA lists High staining in bone marrow hematopoietic cells, placental syncytiotrophoblasts, stomach glandular cells, and bladder urothelial cells (HPA: tissue IHC). If a suitable positive control also fails, review the assay setup and reagent performance (standard IHC practice). |
💡Expected S100P appearanceA credible positive is defined cytoplasmic and nuclear signal in the appropriate cells, potentially strong in HPA High populations; diffuse background or isolated staining of an HPA Not detected cell type needs investigation before scoring (HPA: tissue IHC profile and cell levels; standard IHC practice).
| Cell type and tissue | HPA reports High staining in four listed cell populations, Medium staining in several glandular or squamous epithelial populations, and Low or Not detected staining in others (HPA: tissue IHC). Choose a control by its named cell population, not by organ name alone. |
| Compartment | Tissue IHC describes cytoplasmic and nuclear expression (HPA: tissue IHC profile). UniProt also lists microvillus membrane localization and no transmembrane segment (UniProt P25815: subcellular location; topology). Interpret a putative membrane signal alongside the cellular pattern. |
| Evidence strength | The tissue IHC reliability is Enhanced, but its description notes medium consistency with RNA data and pending restaining (HPA: reliability). HPA019502 has Enhanced IHC validation (HPA: antibodies). These ratings support interpretation while leaving individual slides subject to control review. |
| Regional absence versus broad expression | UniProt reports detection in most tissues except brain, testis, and small intestine (UniProt P25815: tissue specificity). HPA records Low glial staining in cerebral cortex and hippocampus and Medium duodenal glandular staining (HPA: tissue IHC). Treat these as source-specific observations rather than forcing one universal negative-tissue rule. |
| Protein forms | UniProt lists one 1–95 chain, no signal peptide, no propeptide, no listed isoforms, and no glycosylation sites (UniProt P25815: processing; isoforms; glycosylation). The supplied record therefore gives no basis to predict a distinct IHC pattern from a processed or glycosylated S100P form. |
| Situation | Likely cause | Next action |
|---|---|---|
| A listed High cell population stains weakly or not at all. | The expected cells may be absent from the section, or the assay may have failed (HPA: High cell populations; standard IHC practice). | Confirm the cell type on the counterstained section, then check a suitable positive control, detection reagents, and the antibody's validated IHC-P conditions (standard IHC practice). No target-specific fixation sensitivity is supplied. |
| The whole section has broad brown haze. | Nonspecific background or endogenous detection activity can obscure cell boundaries (standard IHC practice). | Compare a matched negative control; review blocking, washes, detection chemistry, and antibody concentration under the validated IHC-P workflow (standard IHC practice). Score only interpretable cell-associated staining. |
| Signal appears only at cell borders. | This differs from the main cytoplasmic and nuclear tissue pattern (HPA: tissue IHC profile), although UniProt lists microvillus membrane localization (UniProt P25815: subcellular location). | Check whether the signal follows identifiable microvilli or broadly outlines unrelated cells; compare expected positive cells and controls before calling it S100P (UniProt P25815: subcellular location; standard IHC practice). |
| Unexpected cells stain more strongly than the expected population. | Misidentified cells, cross-reactivity, or endogenous detection activity may explain a mismatch (standard IHC practice); HPA levels are cell-specific (HPA: tissue IHC). | Reidentify stained cells using tissue morphology and counterstain, then compare an appropriate negative control and an HPA High cell population (HPA: tissue IHC; standard IHC practice). |
| A brain or duodenal section seems to contradict a presumed negative control. | UniProt's broad tissue statement and HPA's cell-level observations differ in scope (UniProt P25815: tissue specificity; HPA: Low glia and Medium duodenal glandular cells). | Use the specific cell population and observed intensity when judging the slide; avoid treating the entire organ as uniformly negative (HPA: tissue IHC). |
| IF/ICC question: where should S100P appear? | HPA reports supported nucleoplasmic localization in ICC-IF, which addresses a different assay from the tissue IHC pattern (HPA: subcellular ICC-IF; tissue IHC). | For IF/ICC interpretation, look for nucleoplasmic signal and use its own controls; use the separate IF/ICC guide for assay setup (HPA: supported nucleoplasm; standard IF practice). |
Experiment evidence
IHC & IF images showing S100P staining
M01963 · IHCImmunohistochemical analysis of paraffin-embedded human bladder carcinoma, using S100P Antibody.
M01963 · IFImmunofluorescent analysis of SW480 cells, using S100P Antibody.
A01963-2 · IFIF analysis of S100P using anti-S100P antibody (A01963-2) and anti-Beta Tubulin antibody (M01857-3). S100P was detected in immunocytochemica
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000163993-S100P/tissue/cerebral+cortex#imid_5453584
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000163993-S100P/tissue/colon#imid_5453502
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000163993-S100P/tissue/liver#imid_5453503
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000163993-S100P/tissue/kidney#imid_5453496
HPA · ICC-IF Hep-G2Human Protein Atlas immunofluorescence, Hep-G2, antibody HPA075251; green = S100P, blue = nucleus, red = microtubules.
HPA · ICC-IF Hep-G2Human Protein Atlas immunofluorescence, Hep-G2, antibody HPA075251; green = S100P, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for S100P IHC & IF
🧪Run placenta first: syncytiotrophoblast cell bodies should stain (HPA: High in placenta syncytiotrophoblasts). Use adipose tissue as the negative tissue; adipocytes should remain unstained (HPA: Not detected in adipocytes). On the positive slide, assess neighboring non-syncytiotrophoblast cells against the no-primary control rather than assuming they are negative (HPA: placenta row specifies syncytiotrophoblasts only).
Positive control tissue: Bone marrow (Hematopoietic cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show S100P in Hep-G2, RT-4, U2OS, with annotated localisation: Nucleoplasm (supported) (HPA subcellular).
Technical controls: Include a no-primary (secondary-only) slide, an isotype-matched control for the primary antibody’s host species and clonality, and a knockout specimen or validated peptide-block control (standard IHC practice). Check the placenta slide for blood-associated endogenous peroxidase signal before interpreting chromogenic staining, and block endogenous peroxidase as appropriate (standard IHC practice).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported, and the M01963 paraffin-section bladder carcinoma caption does not state a fixative (selected product caption: fixative not stated). Antigen retrieval dependence and whether frozen sections or IF are easier are unreported; optimize retrieval empirically for paraffin IHC (supplied evidence: no matched retrieval or format comparison; standard IHC practice). Placental blood-associated peroxidase can complicate chromogenic interpretation, so judge signal against the control slide (standard IHC practice).
HPA tissue IHC evidence for S100P
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Medium consistency between antibody staining and RNA expression data. Pending restaining.). 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 |
|---|---|---|---|---|
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Placenta | Syncytiotrophoblasts - cell body | High | Protein (IHC) | HPA → |
| Stomach | Glandular cells | High | Protein (IHC) | HPA → |
| Urinary bladder | Urothelial cells | High | Protein (IHC) | HPA → |
| Cervix | Glandular 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 → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
| Cerebellum | Cells in granular layer | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced S100P IHC Tips
Troubleshoot S100P staining in paraffin sections by checking retrieval, compartment, cell type, controls and scoring before interpreting chromogenic signal.
How should I adjust retrieval when S100P staining is weak or uneven?
Use Tris-EDTA at pH 9.0 for heat-induced retrieval at 95–98 °C for 20 minutes (page retrieval specification). Keep section thickness, heating vessel, cooling time and antibody incubation consistent while comparing a strongly stained reference section with the weak sample (standard IHC practice; HPA: high in urinary bladder urothelial cells). If nuclear signal remains weak, compare a shorter retrieval exposure on serial sections before increasing primary antibody concentration, because excessive heating can damage morphology (standard IHC practice; UniProt P25815: nuclear localisation). Record both nuclear and cytoplasmic staining separately so a change in compartment visibility is not mistaken for a change in total S100P expression (UniProt P25815: nucleus and cytoplasm; standard IHC practice).
Can fixation explain loss of S100P staining in paraffin sections?
Target-specific fixation sensitivity for S100P is unknown from the supplied evidence, so do not assign weak staining to a particular fixative or fixation duration (supplied evidence: no target-specific fixation study). The catalog image shows S100P staining in paraffin-embedded human bladder carcinoma, but its caption does not state the fixative (catalog antibody M01963: tissue-IHC caption). Compare sections with documented processing histories using the same retrieval, antibody incubation and detection run before attributing differences to fixation (standard IHC practice). Examine preservation of nuclei and tissue architecture alongside staining, and use a reference section to check whether the run worked (standard IHC practice; HPA: high in urinary bladder urothelial cells).
Which S100P staining compartments should I expect, and when is membrane staining plausible?
Score nuclear and cytoplasmic signal because both compartments are reported for S100P in tissue, while nucleoplasmic localisation is supported by cell imaging (HPA: cytoplasmic and nuclear tissue expression; HPA subcellular: supported nucleoplasm). UniProt also places S100P at the microvillus membrane and describes calcium-dependent colocalisation with ezrin, so an apical pattern may warrant inspection in cells with preserved microvilli (UniProt P25815: localisation and EZR interaction). S100P has no transmembrane segment, so a crisp, uniform outline around every cell needs careful assessment rather than automatic acceptance (UniProt P25815: topology; standard IHC practice). Compare the suspected signal with nuclear counterstain, morphology and an appropriate negative control at the same magnification (standard IHC practice).
Could an isoform or modified epitope explain discordant S100P staining?
The supplied record lists 0 isoforms and a single 1–95 protein chain, so an annotated alternative isoform does not explain discordant compartments here (UniProt P25815: isoforms and processing). It lists 0 glycosylation sites and 0 modified residues, without establishing how fixation or retrieval affects this antibody's epitope (UniProt P25815: modifications; supplied evidence: epitope unmapped). The two EF-hand regions span residues 12–47 and 49–84, but their presence alone does not identify the catalog antibody's binding site (UniProt P25815: domains; supplied evidence: epitope unmapped). If staining differs between runs, compare retrieval and controls on adjacent sections before proposing a molecular variant (standard IHC practice).
How can I check a disputed IHC pattern with multiplex IF?
Use IF as a separate validation experiment and pair S100P with a marker that identifies the expected cell population, such as a urothelial marker in urinary bladder sections (HPA: high in urinary bladder urothelial cells; standard IF practice). Choose spectrally separated fluorophores and inspect an unstained section to avoid mistaking tissue autofluorescence for S100P signal (standard IF practice). S100P is reported in nuclei and cytoplasm and lacks a transmembrane segment, so use controlled permeabilisation when testing intracellular signal rather than treating it as an extracellular epitope (UniProt P25815: localisation and topology; standard IF practice). Compare single-stain controls and compartment-resolved images with the chromogenic section, while keeping IF fixation and antibody performance as separate, unverified variables (standard IF practice; supplied evidence: no IF fixation specification).
What should I check when DAB appears throughout the section?
First inspect a no-primary control for chromogen deposition and check whether a peroxidase-block step was included before DAB development (standard chromogenic IHC practice). Compare the staining distribution with hematoxylin counterstain: S100P can be nuclear and cytoplasmic, but diffuse colour over empty space or damaged tissue is not interpretable cellular staining (HPA: nuclear and cytoplasmic expression; standard IHC practice). If background follows edges or folds, repeat staining on an intact section with consistent washes, blocking and incubation conditions (standard IHC practice). Reduce antibody concentration or development time only after checking that a reference section retains its expected cell-specific signal (standard IHC practice; HPA: high in placenta syncytiotrophoblasts).
How should I quantify mixed nuclear and cytoplasmic S100P staining? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring; HPA reports high S100P in urinary bladder urothelial cells and placenta syncytiotrophoblasts, with nuclear and cytoplasmic tissue expression (HPA: tissue profile and positive cells). For each compartment, report the percentage of positive eligible cells and, when intensity is reproducible, an H-score from 0–300 using intensity grades 0–3 (standard IHC practice). Normalize counts to the number of evaluable cells, or report positive-cell density per mm² of viable tissue when counting cells by area (standard IHC practice). Keep thresholds, fields, exclusion rules and reference sections constant across samples, and report nuclear and cytoplasmic results separately (standard IHC practice).
How do I distinguish true S100P positivity from artefact?
Give greatest weight to signal within intact cells and expected compartments: S100P is reported in nuclei and cytoplasm, particularly in urinary bladder urothelial cells, placenta syncytiotrophoblasts and stomach glandular cells (HPA: tissue profile). A uniform extracellular deposit, prominent cut-edge staining or colour concentrated in necrotic material requires review against tissue morphology and a no-primary control (standard IHC practice). Check endogenous peroxidase blocking when DAB appears in cells unrelated to the expected pattern, and compare serial sections processed in the same run (standard chromogenic IHC practice). Treat a negative result cautiously because HPA labels the tissue evidence Enhanced but notes medium RNA–staining consistency and pending restaining (HPA: reliability description).
Boster reagents
Best S100P / Protein S100-P IHC Antibodies
The catalog shows S100P staining in paraffin-embedded human bladder carcinoma and A549 cells (M01963 IHC caption; A01963-2 IF caption). Both antibodies list human reactivity (catalog reactivity).
Real IHC data
Anti-S100P Rabbit Monoclonal Antibody
Cat # M01963
Real IF data
Anti-S100P Antibody ®
Cat # A01963-2
M01963 will render with its IHC image of paraffin-embedded human bladder carcinoma; its applications include IHC (M01963 IHC caption; catalog applications). A01963-2 will render with its IF image of A549 cells; its applications include ICC/IF (A01963-2 IF caption; catalog applications).
Which to pick: Choose M01963 for paraffin-section IHC: it is monoclonal and lists IHC, with an image from paraffin-embedded human bladder carcinoma (catalog clone and applications; M01963 IHC caption). Choose A01963-2 for IF/ICC: it is polyclonal and lists ICC/IF, with an IF image from A549 cells (catalog dilution record and applications; A01963-2 IF caption). Neither has documented cross-species reactivity, since both list human only; the M01963 IHC caption does not report a fixative (catalog reactivity; M01963 IHC caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P25815 (S100P_HUMAN, Protein S100-P).
- Human Protein Atlas. S100P tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. S100P subcellular location (ICC-IF): Localized to the nucleoplasm..
- Human Protein Atlas. S100P antibody validation summary (2 antibodies).
- MTAP in small biopsy samples of pancreatic lesions: a potential diagnostic biomarker. Immunohistochemical, fluorescence in situ hybridization and molecular analysis. Pathologica 2025 — PMC12743368.
- The calcium-binding protein S100P in normal and malignant human tissues. BMC clinical pathology 2008 — PMC2254630.
- Precancerous Lesions and Liver Atrophy as Risk Factors for Hepatolithiasis-Related Death after Liver Resection for Hepatolithiasis. Asian Pacific journal of cancer prevention : APJCP 2020 — PMC8046297.
- S100P is associated with proliferation and migration in nasopharyngeal carcinoma. Oncology letters 2017 — PMC5494647.
- PubMed PMID:1633809 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
- PubMed PMID:1540168 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for S100P (Protein S100-P). Expected localisation Cytoplasmic and nuclear staining (HPA tissue IHC). Antigen retrieval: Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen). Validated IHC antibody: M01963 at 1:50 (the product's own IHC validation image is shown). Controls (HPA): positive Bone marrow (Hematopoietic cells); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human bladder carcinoma tissue; fixative not specified (datasheet M01963); 2. Fixation: Image fixative and duration unreported (datasheet M01963); 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-induced epitope retrieval in Tris-EDTA buffer, pH 9.0 , 20 min at 95–98 °C…; 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 monoclonal (clone AOCH-19) anti-S100P, 1:50 (datasheet M01963); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections. (standard IHC practice; not target-specific); Caveat: Staining consistency with RNA is medium; restaining is pending (HPA tissue IHC); Isoform / epitope: No annotated isoforms or processing; one 1–95 chain (UniProt); Regulation: Up-regulated in pancreatic ductal neoplasia (UniProt). Evidence: UniProt P25815, HPA tissue IHC · Enhanced, HPA ICC-IF · nucleoplasm., Datasheet M01963, PMC12743368, PMC2254630. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/S100P/immunohistochemistry-ihc-guide.