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SFRP4 / Secreted frizzled-related protein 4 · IHC design guide
Design Immunohistochemistry for SFRP4
Plan chromogenic SFRP4 IHC in paraffin sections using endometrial stromal fibroblasts as a strong positive reference (HPA tissue IHC). Score cytoplasmic stromal and occasional glandular staining while accounting for secretion when interpreting its distribution (HPA tissue IHC; UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
SFRP4 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 staining in stromal and some glandular cells (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic stroma in endometrium and fallopian tube; some glands (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet PB9888) | |
| Positive control | Endometrium+1 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 conditions consistent across sections. (standard IHC practice; not target-specific) | |
| Caveat | Secreted SFRP4 may stain away from RNA-positive cells (HPA tissue IHC) | |
| Regulation | Ovarian tumor expression rises with stage (UniProt) | |
| Isoform / epitope | No isoforms; signal 1–18 cleaved; no membrane epitope split (UniProt) |
Section 1
Recommended SFRP4 IHC & IF Protocols
The catalog antibody’s IHC-P protocol (datasheet: PB9888) is followed by published SFRP4 IHC methods for prostate cancer, pancreatic cancer, and adipose tissue (PMC5660209; PMC5617497; PMC5644066).
| Sample | Paraffin-embedded human endometrial carcinoma tissue; fixative not specified (datasheet PB9888) |
| Fixation | Image fixative and duration unreported (datasheet PB9888); 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 PB9888); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet PB9888) |
| Primary antibody | Rabbit anti-SFRP4, 0.5-1μg/ml (datasheet PB9888) |
| Primary incubation | Overnight at 4 °C (datasheet PB9888) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet PB9888) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | SFRP4-positive staining in stromal fibroblasts of endometrium (HPA tissue IHC: High). HPA tissue profile: Selective cytoplasmic expression in stromal cells in both fallopian tube and endometrium as well as a subset of endometrial glandular cells. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 for the catalog antibody (datasheet: PB9888). The prostate study states pH 9 but does not specify retrieval (PMC5660209).
Section 2
What Is the Expected SFRP4 Staining Pattern?
SFRP4 is secreted and has no transmembrane segment (UniProt Q6FHJ7: topology). In paraffin section IHC, expect selective cytoplasmic staining in endometrial and fallopian tube stromal cells, with staining in some endometrial glandular cells (HPA tissue IHC: Enhanced). Endometrial stromal fibroblasts are a strong positive reference (HPA: High). HPA reports only medium consistency between staining and RNA expression, partly because secreted protein may appear away from its site of production (HPA tissue IHC: reliability description).
| Endometrial stromal fibroblasts show strong cytoplasmic chromogen; nearby glandular cells stain variably. | This matches the clearest reference pattern: stromal fibroblasts are High, while only a subset of endometrial glandular cells stains (HPA tissue IHC). Judge the distribution by cell type as well as intensity. Secreted SFRP4 can complicate agreement between protein staining and local RNA expression (HPA tissue IHC: reliability description; UniProt Q6FHJ7: secreted). |
| Signal is predominantly nuclear or forms a sharply defined membrane rim. | That distribution conflicts with HPA's selective cytoplasmic tissue pattern and UniProt's secreted, nontransmembrane annotation (HPA tissue IHC; UniProt Q6FHJ7: topology). Treat it as suspect and compare it with the endometrial positive control and a no primary control; compartment alone cannot identify the specific artifact (general IHC practice). |
| Strong staining appears mainly in cell types reported as negative, such as adipocytes or adrenal glandular cells. | Those cells are Not detected in the supplied HPA tissue profiles (HPA tissue IHC: adipose tissue; adrenal gland). Consider antibody cross-reactivity or endogenous detection activity, especially if staining persists without primary antibody (general IHC practice). HPA's negative profile is a reference pattern, not proof that every individual specimen must be negative. |
| Brown signal spreads across many cells and tissue spaces without a selective stromal pattern. | Diffuse chromogen may reflect background from detection reagents, excess antibody, or incomplete washing (general IHC practice). Because SFRP4 is secreted, some signal beyond the producing cell remains biologically plausible (UniProt Q6FHJ7: secreted; HPA tissue IHC: reliability description). Compare morphology, control sections, and the expected stromal enrichment before calling it positive. |
| An endometrial section has no convincing stromal signal. | That is unexpected for the High stromal fibroblast reference (HPA tissue IHC: endometrium), but one blank section does not establish absent SFRP4. Check tissue identity and preservation, antibody and detection steps, and a run control (general IHC practice). Interpret glandular absence separately because HPA reports staining in only a subset of glandular cells (HPA tissue IHC). |
💡Expected SFRP4 appearanceCall the section positive when endometrial stromal fibroblasts show strong, selective cytoplasmic staining, allowing variable staining in a subset of glands (HPA tissue IHC: High stromal fibroblasts; selective cytoplasmic profile); dominant nuclear or uniform staining of HPA-negative cell types is suspect (HPA tissue IHC; UniProt Q6FHJ7: secreted topology).
| Secreted topology and processing (UniProt Q6FHJ7) | A signal peptide occupies residues 1–18; the annotated secreted chain begins at residue 19, and no transmembrane segment is recorded (UniProt Q6FHJ7: processing; topology). If an antibody recognizes only the removed signal peptide, mature secreted protein may be missed; the supplied record gives no antibody epitope, so this remains a conditional interpretation. |
| Cell distribution and reference intensity (HPA tissue IHC) | Endometrial stromal fibroblasts are High, testicular pachytene spermatocytes are Medium, and the listed adipocytes and adrenal glandular cells are Not detected (HPA tissue IHC). These provide different reference patterns. Match the scored cell population to its own HPA entry; a whole tissue label alone can conceal a selective positive population. |
| Tissue IHC validation and RNA agreement (HPA tissue IHC; HPA antibodies) | HPA marks tissue staining Enhanced and records Enhanced IHC status for HPA009712 and HPA050585 (HPA tissue IHC; HPA antibodies). It also reports medium staining–RNA consistency because secreted protein and RNA can occupy different locations (HPA tissue IHC: reliability description). Use RNA agreement as context, not a requirement for each stained cell. |
| IF/ICC: does the tissue IHC pattern establish a fluorescence pattern? (HPA subcellular; HPA antibodies) | No: HPA lists SFRP4 as Secreted but provides no main subcellular location or ICC–IF image cell lines, and the supplied antibody entries have no ICC status (HPA subcellular; HPA antibodies). The tissue IHC pattern can guide interpretation, but it does not validate a particular IF/ICC compartment or intensity. |
| Situation | Likely cause | Next action |
|---|---|---|
| The positive endometrial control is blank. | A missed staining step, inactive detection reagent, unsuitable retrieval, or low primary concentration is possible (general IHC practice). | Confirm tissue identity, run controls and reagent sequence; review the antibody's IHC instructions before adjusting retrieval or concentration (general IHC practice). The expected reference is High endometrial stromal fibroblast staining (HPA tissue IHC). |
| Only glandular cells stain in endometrium. | A subset of glandular cells can stain, but absent stromal staining misses the principal HPA reference population (HPA tissue IHC). | Inspect stromal morphology and the positive control, then repeat with verified detection steps if needed (general IHC practice). Do not score glandular staining alone as a match to HPA's stromal High pattern (HPA tissue IHC). |
| Adipocytes or adrenal glandular cells stain strongly. | These cell types are Not detected in the supplied reference images; cross-reactivity or endogenous detection activity is possible (HPA tissue IHC; general IHC practice). | Compare with a no primary control and inspect whether the signal follows cells or background deposits; apply the appropriate endogenous activity block if the detection chemistry requires it (general IHC practice). |
| Chromogen is diffuse across the section. | Excess antibody, inadequate washing, or detection background can blur cell boundaries (general IHC practice); secretion can also place SFRP4 beyond its producing cell (UniProt Q6FHJ7: secreted). | Check the no primary control, washing and antibody concentration, then reassess stromal enrichment and morphology (general IHC practice; HPA tissue IHC: selective cytoplasmic profile). |
| Signal appears predominantly nuclear or as a continuous membrane outline. | That compartment differs from the observed cytoplasmic tissue pattern and the nontransmembrane annotation (HPA tissue IHC; UniProt Q6FHJ7: topology). | Review counterstain and cell boundaries, check controls, and repeat staining if the discordance persists (general IHC practice). Treat the location as unconfirmed until the expected stromal pattern is reproduced (HPA tissue IHC). |
| Fallopian tube stroma stains, but endometrial glands are negative. | HPA reports stromal staining in both tissues and staining in only a subset of endometrial glandular cells (HPA tissue IHC). | Score the stromal compartment separately from glands; confirm a functioning positive control before interpreting glandular absence (general IHC practice; HPA tissue IHC: selective cytoplasmic profile). |
Experiment evidence
IHC & IF images showing SFRP4 staining
PB9888 · IHCIHC analysis of SFRP4 using anti-SFRP4 antibody (PB9888). SFRP4 was detected in a paraffin-embedded section of human endometrial carcinoma t
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000106483-SFRP4/tissue/cerebral+cortex#imid_18768428
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000106483-SFRP4/tissue/colon#imid_18768346
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000106483-SFRP4/tissue/liver#imid_18768347
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000106483-SFRP4/tissue/kidney#imid_18768356
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for SFRP4 IHC & IF
🧪Run endometrium first and look for staining in stromal fibroblasts (HPA: High in endometrial stromal fibroblasts). Use adipose tissue adipocytes as the negative tissue (HPA: Not detected in adipocytes); on the endometrial slide, treat unstained neighboring cells as internal background references without assuming a particular cell type is SFRP4-negative (HPA: stromal fibroblasts High).
Positive control tissue: Endometrium (Stromal fibroblasts, 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 SFRP4; derive a cell-line control from the positive tissue's cell type (Stromal fibroblasts) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary (secondary-only) control, host-matched rabbit IgG isotype control, and SFRP4 knockout tissue as a biological negative where available (caption: rabbit primary; standard IHC practice). Quench endogenous peroxidase and assess endogenous biotin background when using the caption’s streptavidin–biotin/DAB detection (caption: SABC with DAB; standard IHC practice).
⚠️Feasibility: A target-specific fixation window and fixation effect are unreported, and the selected PB9888 paraffin-section caption does not state the fixative (caption: fixative not stated). The reported IHC procedure uses heat retrieval in EDTA at pH 8.0; whether this retrieval is required across specimens, or whether frozen sections or IF are easier, is unreported (caption: EDTA retrieval; HPA: no ICC-IF cell-line images). Because SFRP4 is secreted, assess diffuse extracellular staining against the negative controls before assigning it to cells (UniProt Q6FHJ7: Secreted; standard IHC practice).
HPA tissue IHC evidence for SFRP4
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — 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 |
|---|---|---|---|---|
| Endometrium | Stromal fibroblasts | High | Protein (IHC) | HPA → |
| Testis | Pachytene spermatocytes | 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 SFRP4 IHC Tips
Troubleshoot SFRP4 staining in paraffin section chromogenic IHC, with one entry for IF multiplexing (UniProt Q6FHJ7; HPA tissue IHC).
Which retrieval conditions should I try first for weak SFRP4 staining?
Use heat-mediated antigen retrieval in EDTA at pH 8.0 for paraffin sections (datasheet PB9888). The selected tissue IHC image used that retrieval before overnight incubation at 4°C with 1 μg/ml primary antibody (caption PB9888). If staining remains weak, compare retrieval duration on adjacent sections while keeping antibody concentration and detection conditions constant (standard IHC practice). Include a known positive section and a no-primary control in each run to distinguish inadequate retrieval from detection background (HPA: high in endometrial stromal fibroblasts; standard IHC practice). Avoid judging success solely by glandular staining because the reported tissue pattern is selective (HPA tissue IHC).
How should I troubleshoot fixation-related loss of SFRP4 staining?
The selected image identifies a paraffin section but does not report its fixative, so target-specific fixation sensitivity is unknown (caption PB9888). Record fixative, fixation duration and processing history for each case, and compare similarly processed sections before changing antibody conditions (standard IHC practice). Start with heat retrieval in EDTA at pH 8.0, the condition documented for this antibody, and retain a positive tissue control in the same run (datasheet PB9888; HPA: high in endometrial stromal fibroblasts). If signal differs between batches, test retrieval and detection conditions on paired sections; do not attribute the difference to fixation without that comparison (standard IHC practice).
Where should SFRP4 staining appear in an interpretable section?
Assess staining by cell type and compartment because SFRP4 is secreted and has no transmembrane segment (UniProt Q6FHJ7 topology). Selective cytoplasmic staining is reported in stromal cells of endometrium and fallopian tube, with staining in a subset of endometrial glandular cells (HPA tissue IHC). Cytoplasmic signal in ovarian tumor cells is also annotated, so intracellular staining alone does not disqualify a result (UniProt Q6FHJ7 subcellular). Compare adjacent morphology and a no-primary control before calling diffuse extracellular color specific; secreted protein can complicate assignment of signal to its producing cell (UniProt Q6FHJ7 subcellular; standard IHC practice). Score stromal and epithelial compartments separately (standard IHC practice).
Could epitope location explain inconsistent SFRP4 IHC staining?
Check the antibody's stated immunogen or epitope before assigning a failed stain to a protein variant; this record lists 0 isoforms and provides no antibody epitope (UniProt Q6FHJ7; caption PB9888). The 1–18 signal peptide is removed from the annotated 19–346 secreted chain (UniProt Q6FHJ7 processing). Five annotated glycosylation sites and the FZ and NTR domains may matter when evaluating epitope accessibility, but this payload does not establish an effect on this antibody (UniProt Q6FHJ7). Compare retrieval conditions and include a positive control before interpreting absent staining as loss of SFRP4 expression (datasheet PB9888; HPA: high in endometrial stromal fibroblasts; standard IHC practice).
How can I assess SFRP4 in a multiplex IF experiment?
Pair SFRP4 with a marker identifying stromal fibroblasts, an expected positive cell population in endometrium (HPA: high in endometrial stromal fibroblasts). Choose spectrally separated fluorophores and inspect unstained tissue in each channel before selecting the SFRP4 channel, since tissue autofluorescence can mimic weak signal (standard IF practice). Because SFRP4 is secreted and lacks a transmembrane segment, compare nonpermeabilized sections with gently permeabilized sections if the antibody epitope is unknown; permeabilization may be needed to assess the reported cytoplasmic pattern (UniProt Q6FHJ7 topology; HPA tissue IHC; standard IF practice). Validate the IF signal with single-stain and no-primary controls; the provided evidence does not document IF images for this antibody (HPA subcellular; caption PB9888).
What should I change when SFRP4 DAB staining is widespread?
First compare the stained section with a no-primary control and inspect whether color follows tissue edges, folds or damaged areas (standard IHC practice). For peroxidase detection, apply a peroxidase block and verify washing and secondary antibody conditions before increasing primary antibody dilution (standard IHC practice). The selected image used 10% goat serum blocking, 1 μg/ml primary antibody and a biotinylated secondary for 30 minutes at 37°C, followed by SABC and DAB (caption PB9888). Because SFRP4 is secreted, diffuse staining alone cannot identify the producing cells; compare it with the reported stromal pattern and section morphology (UniProt Q6FHJ7 subcellular; HPA tissue IHC).
How should I quantify SFRP4 across tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define stromal and glandular regions before scoring because their reported staining differs in endometrium (HPA tissue IHC). For cellular DAB staining, report percent positive cells and an intensity-weighted H-score on a 0–300 scale, with the scoring rule held constant across sections (standard IHC practice). For extracellular or diffuse signal, report positive area or optical density normalized to the measured tissue area in mm², and keep it separate from cell-based scores (UniProt Q6FHJ7 subcellular; standard IHC practice). Normalize comparisons to the same anatomical compartment and processing batch, and review a positive control for run-to-run staining differences (HPA tissue IHC; standard IHC practice).
How can I distinguish true SFRP4 staining from artefact?
A convincing result should follow identifiable cells and be reproducible across sections, with selective endometrial stromal staining providing a documented reference pattern (HPA tissue IHC; standard IHC practice). Interpret cytoplasmic staining in context: stromal staining is reported by tissue IHC, and ovarian tumor cell cytoplasmic localization is separately annotated (HPA tissue IHC; UniProt Q6FHJ7 subcellular). Treat predominantly nuclear staining, edge-only color, necrotic areas or signal also present in a no-primary control as reasons to investigate artefact (UniProt Q6FHJ7 topology; standard IHC practice). Check endogenous peroxidase background with an appropriate control before assigning DAB color to SFRP4 (standard IHC practice).
Boster reagents
Best SFRP4 / Secreted frizzled-related protein 4 IHC Antibodies
PB9888 has real IHC data from a human endometrial carcinoma paraffin section (catalog IHC image). M03147-1 lists IHC and ICC/IF for human, mouse and rat (catalog applications/reactivity).
Real IHC data
Anti-SFRP4 Antibody ®
Cat # PB9888
The rendered card is PB9888, with IHC staining shown in a human endometrial carcinoma paraffin section (catalog IHC image). Its caption reports heat retrieval in EDTA at pH 8.0 and primary antibody at 1 μg/ml; the fixative is unreported (catalog IHC image).
Which to pick: Choose PB9888 for human paraffin-section IHC because its own caption documents staining under those conditions (catalog IHC image). Choose M03147-1 for IF/ICC or mouse/rat IHC because it lists those applications and species and is monoclonal clone 20S67 (catalog applications/reactivity/clone). No IF image is supplied for M03147-1 (catalog IF image alts).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q6FHJ7 (SFRP4_HUMAN, Secreted frizzled-related protein 4).
- Human Protein Atlas. SFRP4 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. SFRP4 subcellular location (ICC-IF): Secreted.
- Human Protein Atlas. SFRP4 antibody validation summary (2 antibodies).
- SFRP4 gene expression is increased in aggressive prostate cancer. Scientific reports 2017 — PMC5660209.
- Overexpression of miR-135b-5p promotes unfavorable clinical characteristics and poor prognosis via the repression of SFRP4 in pancreatic cancer. Oncotarget 2017 — PMC5617497.
- A Role for Progesterone-Regulated sFRP4 Expression in Uterine Leiomyomas. The Journal of clinical endocrinology and metabolism 2017 — PMC5587057.
- Human epicardial adipose tissue-derived and circulating secreted frizzled-related protein 4 (SFRP4) levels are increased in patients with coronary artery disease. Cardiovascular diabetology 2017 — PMC5644066.
- PubMed PMID:10211996 — UniProt-cited evidence.
- PubMed PMID:12952927 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for SFRP4 (Secreted frizzled-related protein 4). Expected localisation Cytoplasmic staining in stromal and some glandular cells (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet PB9888). Validated IHC antibody: PB9888 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Endometrium (Stromal fibroblasts); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human endometrial carcinoma tissue; fixative not specified (datasheet PB9888); 2. Fixation: Image fixative and duration unreported (datasheet PB9888); 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 PB9888); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet PB9888); 8. Primary antibody: Rabbit anti-SFRP4, 0.5-1μg/ml (datasheet PB9888); 9. Primary incubation: Overnight at 4 °C (datasheet PB9888). Watch for: Fixation: Keep fixation conditions consistent across sections. (standard IHC practice; not target-specific); Caveat: Secreted SFRP4 may stain away from RNA-positive cells (HPA tissue IHC); Isoform / epitope: No isoforms; signal 1–18 cleaved; no membrane epitope split (UniProt); Regulation: Ovarian tumor expression rises with stage (UniProt). Evidence: UniProt Q6FHJ7, HPA tissue IHC · Enhanced, HPA ICC-IF · Secreted, Datasheet PB9888, PMC5660209, PMC5617497. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/SFRP4/immunohistochemistry-ihc-guide.