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FGF19 / Fibroblast growth factor 19 · IHC design guide
Design Immunohistochemistry for FGF19
Plan FGF19 chromogenic IHC on paraffin sections using the catalog antibody’s human IHC evidence (datasheet). Compare cytoplasmic staining and extracellular deposits with the tissue profile, allowing for differences between RNA and protein location in this secreted protein (HPA tissue IHC; UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
FGF19 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 | Extracellular deposits and cytoplasm (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic staining and extracellular deposits across tissues (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Caudate+4 more · see all | |
| Negative control | Bone marrow+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific) | |
| Caveat | Secretion can separate protein staining from RNA expression (UniProt; HPA tissue IHC) | |
| Regulation | Expression control not specified (UniProt) | |
| Isoform / epitope | No isoforms annotated; mature chain 25–216, with no cytoplasmic tail (UniProt) |
Section 1
Recommended FGF19 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is followed by three published FGF19 IHC protocols for prostate, nasopharyngeal, and liver samples (PMC3630260; PMC10899426; PMC6054564).
| Sample | Tissue sections; selected-image fixative not specified (standard IHC workflow) |
| Fixation | Image fixative and duration unreported (datasheet PA1476); 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 citrate buffer, pH 6.0, 20 min at 95–98 °C (standard rule: cytoplasmic / membrane 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 anti-FGF19, 0.5-1μg/ml (datasheet PA1476) |
| 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 | FGF19-positive staining in glial cells of caudate (HPA tissue IHC: High). HPA tissue profile: Extracellular deposits and cytoplasmic expression in all tissues, including gallbladder. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 HIER at 95–98 °C for 20 min (page retrieval); Tris-EDTA pH 9.0 is a published alternative (PMC3630260).
Section 2
What Is the Expected FGF19 Staining Pattern?
FGF19 is secreted and has no transmembrane segment (UniProt O95750 topology). In tissue IHC, expect cytoplasmic staining and extracellular deposits, including in gallbladder (HPA tissue IHC: Approved). Gallbladder and duodenal glandular cells, cerebellar Purkinje cells, caudate glial cells, kidney tubule cells, and small-intestinal glandular cells have high reported staining (HPA tissue IHC). HPA notes that its tissue pattern awaits external verification (HPA reliability description).
| Cytoplasmic staining in gallbladder glandular cells, with extracellular deposits (HPA tissue IHC). | This fits the reported high gallbladder signal and the distribution of a secreted protein (HPA tissue IHC; UniProt O95750: secreted). Compare cell-associated signal with deposits so that extracellular material is not scored as a new positive cell population (standard IHC interpretation). |
| A strong, exclusively nuclear or sharply membrane-confined pattern (HPA tissue IHC: expected cytoplasmic and extracellular pattern). | This does not match the reported tissue pattern or a protein without a transmembrane segment (HPA tissue IHC; UniProt O95750 topology). Check staining specificity and morphology before calling those cells FGF19 positive (standard IHC practice). |
| Signal in liver cholangiocytes or bone-marrow hematopoietic cells (HPA tissue IHC: not detected in these cell populations). | Treat an unexpected positive result as a specificity or endogenous-detection concern; inspect matched negative controls and the staining distribution (standard IHC practice). The HPA finding applies to the named cell populations, not every cell in either tissue (HPA tissue IHC). |
| Uniform haze across tissue and surrounding space, with little cell-to-cell distinction (standard IHC interpretation). | Diffuse background can obscure the cytoplasmic and extracellular pattern reported for FGF19 (HPA tissue IHC). Check a negative control and review blocking, washing, antibody concentration, and detection conditions (standard IHC practice). |
| No staining in gallbladder glandular cells or another reported high-staining population (HPA tissue IHC). | A failed positive control leaves a negative study sample uninterpretable (standard IHC practice). Check tissue preservation and morphology, primary-antibody application, retrieval, detection reagents, and counterstain before inferring absent FGF19 (standard IHC practice). |
💡Expected FGF19 appearanceCall a result positive when high cytoplasmic staining in a reported positive cell population accompanies plausible extracellular deposits; isolated strong nuclear staining is discordant (HPA tissue IHC; UniProt O95750: secreted).
| Secretion and topology (UniProt O95750) | FGF19 has a signal peptide at residues 1–24, a mature chain at 25–216, and no transmembrane segment (UniProt O95750). Interpret deposits alongside cytoplasmic staining; a membrane-only pattern needs a specificity check (HPA tissue IHC; standard IHC practice). |
| Tissue and cell selection (HPA tissue IHC) | Gallbladder, duodenum, and small-intestinal glandular cells are reported high, as are Purkinje cells, caudate glial cells, and kidney tubule cells (HPA tissue IHC). Appendix glandular and bronchial respiratory epithelial cells are medium; their weaker expected staining can complicate control assessment (HPA tissue IHC; standard IHC interpretation). |
| RNA versus protein (HPA tissue IHC) | Gallbladder RNA is tissue enriched, while HPA reports extracellular deposits and cytoplasmic protein staining across tissues (HPA tissue IHC). Because FGF19 is secreted, RNA location and protein location may differ; avoid assigning a deposit to its producing cell from IHC alone (HPA reliability description; UniProt O95750). |
| Strength of validation (HPA tissue IHC; HPA antibodies) | HPA labels its tissue profile Approved and says external verification is pending (HPA reliability description). Antibody HPA036082 is IHC Approved, with no ICC validation listed; these labels do not make an unexpected compartment or cell type automatically specific (HPA antibodies; standard IHC interpretation). |
| IF/ICC Q&A (HPA subcellular; HPA antibodies) | Q: What IF/ICC pattern is established? A: HPA summarizes FGF19 as secreted but supplies no main subcellular location, ICC-IF images, or ICC validation for HPA036082 (HPA subcellular; HPA antibodies). Treat an IF/ICC compartment call as unverified here (HPA subcellular). |
| Situation | Likely cause | Next action |
|---|---|---|
| Reported high-staining gallbladder glandular cells appear negative (HPA tissue IHC). | An assay failure or an unsuitable section can produce an uninformative negative result (standard IHC practice). | Check morphology, primary-antibody application, retrieval, detection reagents, and a positive-control section before interpreting sample negatives (standard IHC practice). |
| The slide shows strong nuclear or membrane-only staining (HPA tissue IHC: cytoplasmic and extracellular pattern). | The compartment conflicts with the observed tissue profile and with the lack of a transmembrane segment (HPA tissue IHC; UniProt O95750 topology). | Inspect morphology and controls, then reassess antibody specificity and detection conditions before assigning FGF19 positivity (standard IHC practice). |
| Liver cholangiocytes stain strongly (HPA tissue IHC: not detected). | Cross-reactivity or endogenous detection activity is possible when a reported negative cell population stains (HPA tissue IHC; standard IHC interpretation). | Compare a no-primary control and a reported positive population on the same staining run; restrict conclusions to identifiable cell types (standard IHC practice; HPA tissue IHC). |
| Broad haze obscures cells and extracellular deposits (standard IHC interpretation). | Excess nonspecific staining or detection background can blur the reported FGF19 pattern (standard IHC practice; HPA tissue IHC). | Review negative controls, blocking, washing, antibody concentration, and detection development; judge the result only after cell boundaries are readable (standard IHC practice). |
| Extracellular material stains while nearby cells appear weak (HPA tissue IHC: extracellular deposits and cytoplasmic expression). | A secreted protein can be seen away from its producing cell; signal location alone does not establish cellular origin (UniProt O95750: secreted; HPA reliability description). | Record deposits separately from cell-associated staining and use cell morphology when scoring named populations (standard IHC practice; HPA tissue IHC). |
| A weak or negative sample disagrees with gallbladder RNA enrichment (HPA tissue IHC). | RNA location need not match protein location for secreted FGF19, and HPA's tissue pattern awaits external verification (HPA reliability description). | Compare the sample with a reported high-staining cell population and assay controls; report the observed IHC result without treating RNA enrichment as proof of protein staining (HPA tissue IHC; standard IHC practice). |
Experiment evidence
IHC & IF images showing FGF19 staining
PA1476 · IHCAnti-FGF19 antibody, PA1476, IHC(P) IHC(P): Human Gallbladder Cancer Tissue
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000162344-FGF19/tissue/cerebral+cortex#imid_9590848
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000162344-FGF19/tissue/colon#imid_9584790
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000162344-FGF19/tissue/liver#imid_9584791
HPA · GallbladderHuman Protein Atlas IHC, Gallbladder. Source: https://www.proteinatlas.org/ENSG00000162344-FGF19/tissue/gallbladder#imid_9584767
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for FGF19 IHC & IF
🧪Run gallbladder first; its glandular cells should stain (HPA: High in gallbladder glandular cells). Use liver cholangiocytes as the negative tissue (HPA: Not detected in liver cholangiocytes), and assess non-glandular cells on the gallbladder slide as candidate internal negatives against the no-primary control (HPA: gallbladder signal annotated in glandular cells).
Positive control tissue: Caudate (Glial cells, HPA High)
Negative control tissue: Bone marrow (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for FGF19; derive a cell-line control from the positive tissue's cell type (Glial cells) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only control, a host-species- and clonality-matched isotype control, and a knockout specimen or immunizing-peptide block as a biological specificity control (standard IHC practice). For chromogenic gallbladder IHC, block endogenous peroxidase and check whether bile pigment could be mistaken for stain; block endogenous biotin if using avidin–biotin detection (standard IHC practice).
⚠️Feasibility: A target-specific fixation window is unreported, and the fixative is unreported in the selected PA1476 IHC-P caption (selected SKU PA1476 caption). Antigen-retrieval dependence is unreported; compare retrieval conditions on paired paraffin sections (standard IHC practice). Frozen sections and IF are not established as easier in the supplied evidence; interpret diffuse or extracellular signal cautiously because FGF19 is secreted (UniProt O95750: Secreted).
HPA tissue IHC evidence for FGF19
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Secreted protein, tissue location of RNA and protein is expected to differ. Pending external verification.). 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 |
|---|---|---|---|---|
| Caudate | Glial cells | High | Protein (IHC) | HPA → |
| Cerebellum | Purkinje cells | High | Protein (IHC) | HPA → |
| Duodenum | Glandular cells | High | Protein (IHC) | HPA → |
| Gallbladder | Glandular cells | High | Protein (IHC) | HPA → |
| Kidney | Cells in tubules | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Liver | Cholangiocytes | Not detected | Protein (IHC) | HPA → |
| Lymph node | Germinal center cells | Not detected | Protein (IHC) | HPA → |
| Oral mucosa | Squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
| Ovary | Ovarian stroma cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced FGF19 IHC Tips
Use matched controls and compartment-aware scoring to troubleshoot FGF19 staining in paraffin sections (UniProt O95750; HPA tissue IHC profile).
How should I adjust retrieval if FGF19 staining is weak in paraffin sections?
Start with citrate buffer at pH 6.0, heated to 95–98 °C for 20 min (page retrieval setting). Compare a known positive gallbladder section and a matched test section in the same staining run; gallbladder glandular cells show high staining in the reference profile (HPA: gallbladder glandular cells, High). If staining remains weak, trial a different retrieval buffer or heating duration on serial sections while holding antibody concentration and detection conditions constant (standard IHC practice). Record cytoplasmic and extracellular signal separately, since both are reported and an apparent gain in one compartment need not represent improved detection in the other (HPA: tissue IHC profile).
Could fixation explain inconsistent FGF19 staining across paraffin blocks?
Target-specific fixation sensitivity is unknown from the supplied evidence, and the PA1476 tissue-IHC caption does not state a fixative (PA1476 tissue-IHC caption). Record fixative, fixation duration in hours, processing history, and section age for each block before comparing staining intensity (standard IHC practice). Stain 2 serial sections from each block in a shared run, using the same citrate pH 6.0, 20 min retrieval and detection settings to limit procedural variation (page retrieval setting; standard IHC practice). If blocks still differ, report the difference as associated with block preparation until matched controls establish a cause; neither the tissue pattern nor the protein record establishes a fixation effect (HPA: tissue IHC profile; UniProt O95750).
Should FGF19 stain cytoplasm, extracellular material, or cell membranes?
Score cytoplasmic staining and extracellular deposits as distinct patterns, because both are described across tissues, including gallbladder (HPA: tissue IHC profile). FGF19 is secreted and has no transmembrane segment, so a sharp, exclusively membrane-bound pattern needs additional validation before assignment to FGF19 (UniProt O95750: subcellular location and topology). Use the 25–216 mature-chain annotation to guide interpretation of antibody epitope information, while avoiding claims about an epitope that has not been mapped here (UniProt O95750: processing). Compare staining with local morphology and a matched negative control; a gallbladder glandular signal has reference support, but extracellular signal cannot by itself identify the producing cell (HPA: gallbladder glandular cells, High; HPA: secreted-protein reliability note).
How do processing and epitope location affect FGF19 IHC interpretation?
The supplied record lists a 216-residue precursor, signal peptide at residues 1–24, mature chain at 25–216, and no annotated isoforms (UniProt O95750: processing and isoforms). Check whether the antibody epitope lies within the mature chain or signal peptide before treating extracellular staining as detection of secreted FGF19; the epitope position is not supplied here (UniProt O95750: processing; antibody evidence supplied). No glycosylation sites or modified residues are annotated, so these annotations provide no basis for choosing a target-specific retrieval adjustment (UniProt O95750: PTM annotations). If staining changes across retrieval conditions, compare serial sections with identical dilution and detection, then document the compartment affected rather than assigning the change to an unverified isoform or modification (standard IHC practice; UniProt O95750: isoforms).
How should I plan a follow-up IF experiment for FGF19?
For a separate IF experiment, multiplex FGF19 with a validated glandular-cell marker and inspect gallbladder glandular cells, which have high reference IHC staining (HPA: gallbladder glandular cells, High). Choose a fluorophore in a channel with low measured tissue autofluorescence, and include single-color and unstained controls before interpreting overlap (standard IF practice). Because FGF19 is secreted and lacks a transmembrane segment, test permeabilised sections for intracellular signal and nonpermeabilised sections for accessible extracellular signal; the antibody epitope is unspecified, so neither condition is guaranteed to work (UniProt O95750: location and topology; standard IF practice). Keep IF findings separate from the paraffin-section chromogenic result, since the supplied PA1476 caption documents tissue IHC only (PA1476 tissue-IHC caption).
What should I check when FGF19 staining appears diffuse or widespread?
First compare the stained section with a no-primary control, because detection chemistry and tissue components can produce signal independent of primary-antibody binding (standard IHC practice). For chromogenic detection, check that the peroxidase block was applied before DAB and compare matched sections using the same antibody dilution and development time (standard IHC practice). Diffuse extracellular staining is plausible for a secreted protein, and the reference profile describes extracellular deposits across tissues; do not classify every diffuse region as background solely from its shape (UniProt O95750: secreted; HPA: tissue IHC profile). Conversely, map signal around tissue edges, folds, and necrotic areas separately, then confirm any proposed cellular pattern against morphology and a reference-positive area (standard IHC practice; HPA: gallbladder glandular cells, High).
How can I quantify FGF19 staining without mixing cellular and extracellular signals? ⚠ ANSWER MARKED FOR VERIFICATION
Define glandular-cell and extracellular regions before scoring, because the reference profile includes both cytoplasmic expression and extracellular deposits (HPA: tissue IHC profile). For cells, record the percentage positive and an H-score using intensity grades 0–3; normalise the count to the number of eligible cells in the annotated region (standard IHC scoring practice). For deposits, report positive area or deposit density per mm² of evaluable tissue, excluding folds and necrosis by a stated rule (standard IHC image-analysis practice). Keep acquisition, DAB development, and thresholds consistent across slides, and report the cellular and extracellular measures separately because secreted FGF19 may be found away from its source cells (standard IHC practice; HPA: secreted-protein reliability note).
Which findings support genuine FGF19 staining rather than an artefact?
Look for reproducible cytoplasmic or extracellular staining in intact tissue, with high gallbladder glandular-cell staining as one reference pattern (HPA: tissue IHC profile; HPA: gallbladder glandular cells, High). A purely sharp membrane pattern warrants review because FGF19 is secreted and has no transmembrane segment, although morphology alone cannot establish specificity (UniProt O95750: location and topology; standard IHC practice). Compare signal at section edges and necrotic regions with intact central tissue, and check the no-primary control for endogenous detection signal (standard IHC practice). Interpret a negative result with the relevant cell type and control in view: HPA reports liver cholangiocytes as not detected, while gallbladder glandular cells are High, and secreted-protein RNA and protein locations may differ (HPA: liver cholangiocytes, Not detected; HPA: gallbladder glandular cells, High; HPA: reliability note).
Boster reagents
Best FGF19 / Fibroblast growth factor 19 IHC Antibodies
The catalog contains one human-reactive anti-FGF19 antibody with an IHC(P) image from human gallbladder cancer tissue (catalog: reactivity; PA1476 image caption). No IF image is supplied (catalog: IF images).
Real IHC data
Anti-Fibroblast growth factor 19 FGF19 Antibody ®
Cat # PA1476
PA1476 is listed for human IHC (catalog: applications and reactivity). Its IHC(P) image shows human gallbladder cancer tissue (PA1476 image caption).
Which to pick: Choose PA1476 for paraffin-section tissue IHC because its own image caption documents IHC(P) in human gallbladder cancer tissue; the fixative is unreported (PA1476 image caption). No SKU is documented for IF/ICC: PA1476 lists IHC and WB, with no IF image or dilution (catalog: applications, IF images and IF dilution). No cross-species option is documented because PA1476 lists human reactivity only; its host is rabbit, and its clone is unreported (catalog: reactivity, host and clone).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O95750 (FGF19_HUMAN, Fibroblast growth factor 19).
- Human Protein Atlas. FGF19 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. FGF19 subcellular location (ICC-IF): Secreted.
- Human Protein Atlas. FGF19 antibody validation summary (1 antibodies).
- The impact of FGF19/FGFR4 signaling inhibition in antitumor activity of multi-kinase inhibitors in hepatocellular carcinoma. Scientific reports 2021 — PMC7935880.
- Endocrine fibroblast growth factor FGF19 promotes prostate cancer progression. Cancer research 2013 — PMC3630260.
- FGF19 promotes nasopharyngeal carcinoma progression by inducing angiogenesis via inhibiting TRIM21-mediated ANXA2 ubiquitination. Cellular oncology (Dordrecht, Netherlands) 2024 — PMC10899426.
- Dysregulation of serum bile acids and FGF19 in alcoholic hepatitis. Journal of hepatology 2018 — PMC6054564.
- PubMed PMID:9931477 — UniProt-cited evidence.
- PubMed PMID:10525310 — UniProt-cited evidence.
- PubMed PMID:12975309 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for FGF19 (Fibroblast growth factor 19). Expected localisation Extracellular deposits and cytoplasm (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: PA1476 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Caudate (Glial cells); negative Bone marrow. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Tissue sections; selected-image fixative not specified (standard IHC workflow); 2. Fixation: Image fixative and duration unreported (datasheet PA1476); 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 citrate buffer, pH 6.0 , 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 anti-FGF19, 0.5-1μg/ml (datasheet PA1476); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific); Caveat: Secretion can separate protein staining from RNA expression (UniProt; HPA tissue IHC); Isoform / epitope: No isoforms annotated; mature chain 25–216 , with no cytoplasmic tail (UniProt); Regulation: Expression control not specified (UniProt). Evidence: UniProt O95750, HPA tissue IHC · Approved, HPA ICC-IF · Secreted, Datasheet PA1476, PMC3630260, PMC10899426. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/FGF19/immunohistochemistry-ihc-guide.