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FAH / Fumarylacetoacetase · IHC design guide
Design Immunohistochemistry for FAH
Use hepatocytes and kidney proximal tubules as high-staining reference cells for FAH in paraffin-section IHC (HPA tissue IHC). The catalog antibody has an IHC dilution range of 2–5 μg/ml (datasheet A02072-1), and the expected liver and kidney pattern is cytoplasmic (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
FAH 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 in liver and kidney (HPA tissue IHC) | |
| Staining pattern | Hepatocytes and proximal tubules stain cytoplasm (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A02072-1) | |
| Positive control | Cerebellum+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 samples (standard IHC practice; not target-specific) | |
| Caveat | High nuclear staining in Bergmann glia is also reported (HPA tissue IHC) | |
| Regulation | Liver-enhanced expression (HPA tissue RNA) | |
| Isoform / epitope | 2 isoforms; epitope coverage is unspecified (UniProt) |
Section 1
Recommended FAH IHC & IF Protocols
The catalog antibody’s IHC-P protocol is accompanied by four published FAH immunohistochemistry protocols for liver or liver and kidney sections (PMC5957080; PMC4561890; PMC4096906; PMC3786690).
| Sample | Paraffin-embedded human liver cancer tissue; fixative not specified (datasheet A02072-1) |
| Fixation | Image fixative and duration unreported (datasheet A02072-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: EDTA pH 8.0 (datasheet A02072-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A02072-1) |
| Primary antibody | Rabbit anti-FAH, 2-5 μg/ml (datasheet A02072-1) |
| Primary incubation | Overnight at 4 °C (datasheet A02072-1) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A02072-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | FAH-positive staining in bergmann glia - nucleus of cerebellum (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in the liver and kidney. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet: A02072-1); follow each published protocol’s stated retrieval conditions when reproducing it (PMC5957080; PMC4096906).
Section 2
What Is the Expected FAH Staining Pattern?
FAH should show predominantly cytoplasmic staining in hepatocytes and kidney proximal tubules (HPA tissue IHC: High in both). Liver and kidney are its main expression sites (UniProt P16930 tissue specificity). FAH has no annotated transmembrane segment, while UniProt assigns no subcellular location (UniProt P16930 topology and subcellular record). HPA rates its tissue IHC evidence Enhanced, with medium consistency between staining and RNA data (HPA tissue IHC reliability).
| Strong cytoplasmic stain in hepatocytes and proximal tubule cell bodies. | This matches the principal positive pattern (HPA tissue IHC: High in hepatocytes and proximal tubules; cytoplasmic profile). Compare the signal with tissue architecture and a matched negative control before scoring it as specific staining (general IHC practice). |
| Predominantly nuclear stain in liver or kidney, with little cytoplasmic signal. | Investigate a compartment mismatch: HPA describes cytoplasmic tissue staining, although it also reports nuclear Bergmann glia staining and additional nucleoplasmic localization by ICC-IF (HPA tissue IHC; HPA subcellular). Nuclear signal alone therefore does not establish either specificity or artefact; check the cell type and controls. |
| Strong stain in a cell type recorded as undetected, such as adipocytes. | Treat this as unexpected for that cell type (HPA tissue IHC: adipocytes Not detected). Compare with the no-primary control and the staining in known-positive tissue; persistent staining may reflect antibody cross-reactivity, while control staining may reflect endogenous detection activity (general IHC practice). |
| Diffuse stain across cells and extracellular spaces, obscuring cell boundaries. | This does not reproduce HPA's cell-associated cytoplasmic liver and kidney profile (HPA tissue IHC). Assess background with a no-primary control and review blocking, washes, and detection conditions (general IHC practice); the appearance alone cannot identify which step caused it. |
| No signal in hepatocytes or kidney proximal tubules. | A negative result in these reference-positive cells needs technical review before biological interpretation (HPA tissue IHC: High in both). Confirm tissue integrity and assay controls, then review retrieval, antibody dilution, and detection conditions as general IHC variables; no FAH-specific retrieval condition is supplied. |
💡Expected FAH appearanceCall positive when hepatocytes or proximal tubule cell bodies show clear, predominantly cytoplasmic staining, expected to be High by HPA; diffuse background or isolated staining in an HPA-undetected cell type is a suspect positive requiring controls (HPA tissue IHC; general IHC practice).
| Tissue and cell selection | Use liver hepatocytes or kidney proximal tubules to judge whether the assay can reveal the expected pattern (HPA tissue IHC: High). HPA also reports Medium staining in several other cell types and Low staining in listed glandular cells, so signal strength should be interpreted by cell type (HPA tissue IHC). |
| Antibody evidence | HPA lists HPA041370 and HPA044093 as IHC Enhanced (HPA antibodies). This supports the reported tissue pattern, while the tissue profile's stated RNA agreement is medium; retain slide-level controls when interpreting an unexpected distribution (HPA tissue IHC reliability; general IHC practice). |
| Compartment and IF/ICC Q&A | What should IF/ICC show? Mainly cytosol, with additional nucleoplasm (HPA subcellular). In tissue IHC, HPA describes cytoplasmic liver and kidney staining but also High nuclear staining in Bergmann glia (HPA tissue IHC). These observations are context-specific; no IF/ICC protocol is supplied here. |
| Isoforms and epitope coverage | UniProt lists two FAH isoforms (UniProt P16930 isoforms). The supplied records give no antibody epitope or isoform-specific staining result, so the observed IHC pattern cannot be assigned to either isoform from these data alone. |
| Fixation sensitivity | Target-specific fixation effects are not established by the supplied assay evidence. Verify with a matched IHC source before attributing a result to fixation. |
| Situation | Likely cause | Next action |
|---|---|---|
| Positive liver or kidney section is blank. | The result conflicts with HPA's High staining in hepatocytes and proximal tubules; the cause cannot be assigned from the blank slide alone (HPA tissue IHC). | Check tissue preservation, a working detection control, primary antibody use, and chromogen development; then optimize retrieval and dilution as general IHC practice. No FAH-specific condition is supplied. |
| Only weak, hard-to-score stain appears in expected-positive cells. | A weak result differs from the HPA High reference pattern, although slide conditions and scoring can affect its visibility (HPA tissue IHC; general IHC practice). | Compare hepatocytes or proximal tubules with a matched negative control; review retrieval, dilution, incubation, and detection settings as general IHC practice without assuming a FAH-specific fixation effect. |
| Nuclear staining dominates in liver or kidney. | That distribution differs from HPA's cytoplasmic tissue profile there; HPA's Bergmann glia and ICC-IF observations show that nuclear FAH-associated signal can occur in other contexts (HPA tissue IHC; HPA subcellular). | Identify the stained cell type, inspect the cytoplasmic signal, and compare controls before calling the nuclear stain artefactual or specific (general IHC practice). |
| Adipocytes or another HPA-undetected cell type stain strongly. | The cell-specific result conflicts with HPA's Not detected entry and may reflect cross-reactivity or detection background (HPA tissue IHC; general IHC practice). | Review morphology alongside a positive reference tissue and no-primary control; if the no-primary slide stains, investigate endogenous detection activity (general IHC practice). |
| Brown signal covers much of the section without a clear cellular pattern. | Widespread background can obscure the expected cytoplasmic, cell-associated result (HPA tissue IHC; general IHC practice). | Inspect a no-primary control, wash stringency, blocking, and chromogen development as general IHC checks; score FAH only where cell boundaries and the expected compartment remain interpretable. |
| Liver and kidney differ markedly in staining intensity. | HPA classifies hepatocytes and proximal tubules as High, but that category does not specify equal intensity on every section (HPA tissue IHC). | Compare the named cell populations rather than whole-section color, then check matched processing and assay controls before attributing the difference to FAH expression (general IHC practice). |
Experiment evidence
IHC & IF images showing FAH staining
A02072-1 · IHCIHC analysis of FAA/FAH using anti-FAA/FAH antibody (A02072-1). FAA/FAH was detected in a paraffin-embedded section of human liver cancer ti
A02072-1 · IHCIHC analysis of FAA/FAH using anti-FAA/FAH antibody (A02072-1). FAA/FAH was detected in a paraffin-embedded section of mouse liver tissue. H
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000103876-FAH/tissue/cerebral+cortex#imid_10645881
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000103876-FAH/tissue/colon#imid_13960993
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000103876-FAH/tissue/liver#imid_10645808
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000103876-FAH/tissue/kidney#imid_10645809
HPA · ICC-IF HELHuman Protein Atlas immunofluorescence, HEL, antibody HPA044093; green = FAH, blue = nucleus, red = microtubules.
HPA · ICC-IF HELHuman Protein Atlas immunofluorescence, HEL, antibody HPA044093; green = FAH, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for FAH IHC & IF
🧪Run liver first: hepatocytes should stain strongly (HPA: High in hepatocytes). Use adipose tissue as the negative comparator (HPA: Not detected in adipocytes); on the liver slide, compare hepatocyte staining with adjacent nonhepatocyte cells as an internal background reference, without assuming those cells are FAH-negative.
Positive control tissue: Cerebellum (Bergmann glia - nucleus, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show FAH in HEL, Hep-G2, U2OS, NIH 3T3, with annotated localisation: Cytosol (approved) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control, an isotype-matched rabbit IgG control (selected-SKU caption: rabbit primary), and FAH-knockout tissue as a biological negative control. For liver HRP–DAB staining (selected-SKU caption: HRP–DAB), quench endogenous peroxidase and check for pigment-related background.
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the fixative is unreported in the selected-SKU tissue-IHC caption. Heat retrieval in EDTA at pH 8.0 was used for the paraffin-section image (selected-SKU caption), but a retrieval dependency is unreported. There is insufficient supplied evidence to say frozen sections or tissue IF are easier; inspect liver pigment when interpreting DAB signal (selected-SKU caption: liver tissue and DAB detection).
HPA tissue IHC evidence for FAH
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Medium consistency between antibody staining and RNA expression data.). 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 |
|---|---|---|---|---|
| Cerebellum | Bergmann glia - nucleus | High | Protein (IHC) | HPA → |
| Kidney | Proximal tubules (cell body) | High | Protein (IHC) | HPA → |
| Liver | Hepatocytes | High | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Medium | Protein (IHC) | HPA → |
| Fallopian tube | Ciliated cells (tip of cilia) | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Bronchus | Basal cells | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
| Cerebral cortex | Endothelial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced FAH IHC Tips
Troubleshoot FAH staining in paraffin sections by checking retrieval, compartment, cell identity and controls before comparing staining intensity.
What retrieval should I use when FAH staining is weak in paraffin sections?
Start with heat-mediated retrieval in EDTA at pH 8.0 (datasheet A02072-1). The selected paraffin-section example used this retrieval before overnight primary incubation at 4°C, but its caption gives no retrieval heating time (datasheet A02072-1). If staining remains weak, vary heating duration on matched sections while holding the primary concentration at the reported 2 μg/ml, and include a no-primary control to detect retrieval-related background (datasheet A02072-1; standard IHC practice). Judge improvement by clearer staining in hepatocytes or kidney proximal tubules, while checking that section edges have not acquired diffuse colour (HPA tissue IHC; standard IHC practice).
How should I troubleshoot apparent loss of FAH staining after fixation?
Target-specific sensitivity of FAH staining to fixation is unknown from the supplied evidence (selected IHC caption: fixative not stated). The product example identifies a paraffin-embedded section but does not identify its fixative, so its staining cannot establish performance after a particular fixation schedule (datasheet A02072-1). Record the fixative, fixation interval and processing history for each specimen, then compare matched sections using the documented EDTA pH 8.0 retrieval and 2 μg/ml primary concentration (datasheet A02072-1; standard IHC practice). Include a known positive liver or kidney section in the same run to distinguish a specimen problem from run failure (HPA tissue IHC; standard IHC practice).
How should I assess FAH staining that appears nuclear or membranous?
Prioritise cytoplasmic staining in hepatocytes and kidney proximal tubules when reading paraffin sections (HPA tissue IHC). FAH is mainly cytosolic, with an additional nucleoplasmic location reported by cell imaging, so limited nuclear signal can be assessed alongside the cytoplasmic pattern (HPA subcellular). A sharp continuous membrane rim deserves scrutiny because the FAH record lists no transmembrane segment (UniProt P16930 topology). Compare adjacent cells and a no-primary control, and check whether DAB colour follows section edges or damaged areas rather than cell bodies (standard IHC practice). Record nuclear and cytoplasmic scores separately instead of folding an isolated nuclear signal into a general positive score (standard IHC practice).
Could FAH isoforms or epitope accessibility explain discordant IHC staining?
FAH has 2 listed isoforms, but the supplied antibody caption does not identify its epitope or establish isoform selectivity (UniProt P16930 isoforms; datasheet A02072-1). Its listed modified residues include phosphoserine at positions 92 and 309 and phosphotyrosine at 395; their effects on this antibody’s tissue staining are unknown (UniProt P16930 modified residues; datasheet A02072-1). Review any available epitope documentation before attributing a negative area to isoform expression, and compare it with matched positive liver or kidney sections (UniProt P16930 tissue specificity; standard IHC practice). Keep retrieval at EDTA pH 8.0 during that comparison so a protocol change does not confound the result (datasheet A02072-1; standard IHC practice).
How can I use IF to check an ambiguous FAH IHC pattern?
On a separately validated IF preparation, pair FAH with a validated hepatocyte or proximal-tubule marker to test whether the signal belongs to an expected positive cell type (HPA tissue IHC; standard IF practice). Choose a fluorophore channel after inspecting unstained tissue for autofluorescence, and include single-stain controls when assessing overlap (standard IF practice). FAH is mainly cytosolic, has an additional nucleoplasmic location, and has no listed transmembrane segment; permeabilise cells to access intracellular epitopes while checking that extraction has not erased the cytosolic signal (HPA subcellular; UniProt P16930 topology; standard IF practice). The paraffin IHC caption supplies no IF fixation or permeabilisation condition, so optimise those conditions within the IF assay (datasheet A02072-1; standard IF practice).
What should I check when DAB background obscures FAH-positive cells?
The selected paraffin-section example used 10% goat serum blocking, 2 μg/ml primary antibody overnight at 4°C, and peroxidase-based DAB detection (datasheet A02072-1). Run no-primary and detection-only controls to identify secondary-reagent or endogenous-peroxidase colour, and apply a peroxidase block as a general chromogenic IHC step (standard IHC practice). If diffuse colour persists, compare shorter primary incubation or lower primary concentration against the reported condition on adjacent sections, keeping DAB development consistent (datasheet A02072-1; standard IHC practice). Preserve hepatocyte or proximal-tubule cell-body staining while reducing signal in extracellular space, section folds and edges (HPA tissue IHC; standard IHC practice).
How should I quantify heterogeneous FAH staining across tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION
Score FAH in a defined cell population, such as hepatocytes or kidney proximal tubules, because both show high protein staining in the supplied tissue profile (HPA tissue IHC). For chromogenic sections, record the percentage of positive target cells and an intensity-based H-score, with the intensity scale and threshold fixed before comparing groups (standard IHC practice). Normalise positive-cell counts to the total number of evaluable target cells, or area measurements to evaluable tissue area in mm², and exclude folds and necrosis by a consistent rule (standard IHC practice). Report cytoplasmic and nuclear staining separately because the reported locations differ in prominence (HPA subcellular; standard IHC practice).
How can I distinguish true FAH positivity from staining artefact?
Give greatest weight to cell-body staining in hepatocytes or kidney proximal tubules, which are high in the supplied tissue profile, and assess the pattern against expected cytosolic enrichment (HPA tissue IHC; HPA subcellular). Treat an isolated membrane rim cautiously because FAH has no listed transmembrane segment; evaluate nuclear colour separately because an additional nucleoplasmic location is reported (UniProt P16930 topology; HPA subcellular). Compare questionable areas with intact neighbouring tissue and no-primary controls, looking for edge staining, necrosis-associated colour or endogenous-peroxidase signal (standard IHC practice). A positive control confirms that the run can detect FAH, while morphology and controls determine whether a particular stained area is interpretable (standard IHC practice).
Boster reagents
Best FAH / Fumarylacetoacetase IHC Antibodies
The catalog antibody has IHC data from paraffin sections of human liver cancer tissue and mouse and rat liver (catalog IHC captions). No IF data are supplied (catalog payload).
Real IHC data
Anti-FAA/FAH Antibody ®
Cat # A02072-1
A02072-1 is the only SKU listed and is validated for IHC in human, mouse and rat (catalog applications and reactivity). Its IHC captions show paraffin sections of human liver cancer tissue, mouse liver and rat liver (catalog IHC captions).
Which to pick: Choose A02072-1 for paraffin-section IHC; its captions document staining at 2 μg/ml after heat retrieval in EDTA at pH 8.0 (A02072-1 IHC captions). It is also the cross-species choice for human, mouse and rat IHC (catalog reactivity and IHC captions). No IF/ICC-validated SKU is listed (catalog applications and IF image alts); the fixative used for the pictured paraffin sections is unreported (A02072-1 IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P16930 (FAAA_HUMAN, Fumarylacetoacetase).
- Human Protein Atlas. FAH tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. FAH subcellular location (ICC-IF): Mainly localized to the cytosol. In addition localized to the nucleoplasm..
- Human Protein Atlas. FAH antibody validation summary (2 antibodies).
- Noninvasive 3-dimensional imaging of liver regeneration in a mouse model of hereditary tyrosinemia type 1 using the sodium iodide symporter gene. Liver transplantation : official publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society 2015 — PMC5957080.
- Natural Killer Cells-Produced IFN-γ Improves Bone Marrow-Derived Hepatocytes Regeneration in Murine Liver Failure Model. Scientific reports 2015 — PMC4561890.
- Fumarylacetoacetate hydrolase deficient pigs are a novel large animal model of metabolic liver disease. Stem cell research 2014 — PMC4096906.
- Therapeutic liver reconstitution with murine cells isolated long after death. Gastroenterology 2010 — PMC3786690.
- PubMed PMID:1998338 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:17974005 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for FAH (Fumarylacetoacetase). Expected localisation Cytoplasmic in liver and kidney (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A02072-1). Validated IHC antibody: A02072-1 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Cerebellum (Bergmann glia - nucleus); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human liver cancer tissue; fixative not specified (datasheet A02072-1); 2. Fixation: Image fixative and duration unreported (datasheet A02072-1); 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: EDTA pH 8.0 (datasheet A02072-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A02072-1); 8. Primary antibody: Rabbit anti-FAH, 2-5 μg/ml (datasheet A02072-1); 9. Primary incubation: Overnight at 4 °C (datasheet A02072-1). Watch for: Fixation: Keep fixation consistent across samples (standard IHC practice; not target-specific); Caveat: High nuclear staining in Bergmann glia is also reported (HPA tissue IHC); Isoform / epitope: 2 isoforms; epitope coverage is unspecified (UniProt); Regulation: Liver-enhanced expression (HPA tissue RNA). Evidence: UniProt P16930, HPA tissue IHC · Enhanced, HPA ICC-IF · Mainly localized to the cytosol. In addition localized to the…, Datasheet A02072-1, PMC5957080, PMC4561890. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/FAH/immunohistochemistry-ihc-guide.