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HAO1 / 2-Hydroxyacid oxidase 1 · IHC design guide
Design Immunohistochemistry for HAO1
Plan chromogenic HAO1 IHC in paraffin sections using the IHC-validated antibody (datasheet A09159-2). Interpret granular hepatocyte cytoplasmic staining (HPA tissue IHC) in light of the protein’s peroxisomal matrix location (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
HAO1 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 | Granular hepatocyte cytoplasm (HPA tissue IHC); peroxisomal matrix expected (UniProt) | |
| Staining pattern | Hepatocytes show granular cytoplasmic staining (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A09159-2) | |
| Positive control | Liver+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 consistent across sections. (standard IHC practice; not target-specific) | |
| Caveat | Presumed off-target staining was observed and disregarded (HPA tissue IHC) | |
| Regulation | Liver-enriched expression (HPA tissue IHC) | |
| Isoform / epitope | No annotated isoforms; one chain spanning 1–370 (UniProt) |
Section 1
Recommended HAO1 IHC & IF Protocols
The catalog antibody protocol is paired with one published HAO1 IHC protocol using breast cancer tissue microarrays (PMC11545845).
| Sample | Paraffin-embedded mouse liver tissue; fixative not specified (datasheet A09159-2) |
| Fixation | Image fixative and duration unreported (datasheet A09159-2); 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 A09159-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A09159-2) |
| Primary antibody | Rabbit anti-HAO1, 2-5 μg/ml (datasheet A09159-2) |
| Primary incubation | Overnight at 4 °C (datasheet A09159-2) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A09159-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | HAO1-positive staining in hepatocytes of liver (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression with a granular pattern in liver. No signal in the no-primary control. |
💡Decision noteStart with EDTA pH 8.0 heat retrieval for the catalog antibody (datasheet A09159-2); consider citrate pH 6.0 when adapting the published protocol (PMC11545845).
Section 2
What Is the Expected HAO1 Staining Pattern?
In paraffin-section IHC, expect strong granular cytoplasmic HAO1 staining in hepatocytes (HPA: high in hepatocytes; granular cytoplasmic liver profile). This fits its peroxisome-matrix location and lack of a transmembrane segment (UniProt Q9UJM8: subcellular location and topology). HPA rates the tissue IHC evidence Enhanced, while noting that presumed off-target staining was observed and disregarded (HPA: tissue IHC reliability).
| Hepatocytes show strong cytoplasmic granules, with cell outlines and nuclei available for comparison. | This is the expected positive pattern in liver (HPA: high in hepatocytes; granular cytoplasmic liver profile). Granules are consistent with peroxisome-matrix localisation (UniProt Q9UJM8: subcellular location); the IHC pattern alone does not prove each granule is a peroxisome. |
| Signal is predominantly nuclear or traces the plasma membrane instead of appearing as cytoplasmic granules. | Treat that distribution as discordant with the reported pattern (HPA: granular cytoplasmic liver profile; UniProt Q9UJM8: peroxisome matrix, no transmembrane segment). Check detection controls and repeat the localisation assessment before assigning it to HAO1. |
| Strong staining appears in a cell population reported as HAO1-negative, such as adipocytes in adipose tissue. | Investigate cross-reactivity or endogenous detection activity rather than counting it as a confirmed positive (HPA: adipocytes not detected; HPA: presumed off-target staining observed and disregarded). Keratinocytes require separate interpretation because HPA reports medium staining in skin (HPA: keratinocytes, Medium). |
| Chromogen spreads across the section or stains many unrelated structures without a clear cell pattern. | Diffuse background cannot establish HAO1 localisation. Compare a no-primary control, inspect blocking and washes, and judge specific staining against the expected hepatocyte granules (standard IHC practice; HPA: granular cytoplasmic liver profile). |
| A liver section has no convincing hepatocyte signal despite otherwise interpretable tissue morphology. | This conflicts with the expected positive control (HPA: hepatocytes, High; UniProt Q9UJM8: highly expressed in liver). First assess the run's controls and detection steps; a single negative section does not establish absent HAO1 expression. |
💡Expected HAO1 appearanceCall a result positive when hepatocytes show high granular cytoplasmic staining (HPA: hepatocytes, High; granular liver profile), consistent with peroxisome-matrix HAO1 (UniProt Q9UJM8: subcellular location); dominant nuclear, membrane-like or indiscriminate background signal is discordant with that pattern (HPA: liver profile; UniProt Q9UJM8: no transmembrane segment).
| Subcellular location | HAO1 is assigned to the peroxisome matrix (UniProt Q9UJM8: subcellular location), and liver IHC shows cytoplasmic granules (HPA: tissue IHC profile). Use both observations to judge localisation; routine chromogenic IHC does not identify individual organelles on its own (standard IHC interpretation). |
| Tissue and cell distribution | Liver hepatocytes are a strong positive reference, while skin keratinocytes have medium staining (HPA: positive tissue IHC). Adipocytes and several listed cell populations are not detected (HPA: negative tissue IHC). Interpret unexpected staining against the specific cell type, not a blanket rule for all nonliver tissue. |
| Antibody evidence | HPA049552 and HPA072442 each have Enhanced IHC status (HPA: antibody validation). HPA's overall tissue reliability is also Enhanced, with presumed off-target staining observed and disregarded (HPA: tissue IHC reliability). Validation supports use of the reported pattern but does not make every stained structure target-specific. |
| Topology and processing | The protein has no transmembrane segment, no signal peptide, no propeptide and one annotated chain spanning residues 1–370 (UniProt Q9UJM8: topology and processing). These annotations support a nonmembranous interpretation; they supply no target-specific retrieval or fixation setting. |
| IF/ICC Q&A: what localisation is reported? | HPA reports supported vesicle localisation in ICC-IF and lists U-251MG images (HPA: subcellular ICC-IF). UniProt assigns HAO1 to the peroxisome matrix (UniProt Q9UJM8: subcellular location). Use the IF/ICC guide for its own design; the vesicle label does not change the granular cytoplasmic liver IHC expectation (HPA: tissue IHC profile). |
| Retrieval and fixation evidence | No HAO1-specific fixation sensitivity or antigen-retrieval condition is supplied by UniProt or HPA here. If a run fails, evaluate retrieval as a general paraffin-IHC workflow variable (standard IHC practice); do not infer that a particular fixation condition changes HAO1 staining. |
| Situation | Likely cause | Next action |
|---|---|---|
| Hepatocyte signal is absent or weak in the positive liver section. | Possible run failure or insufficient assay sensitivity; the expected liver signal is high (HPA: hepatocytes, High). The supplied sources do not identify an HAO1-specific fixation or retrieval failure mode. | Verify section integrity, primary and detection reagents, chromogen development and run controls; then optimize retrieval and antibody conditions as general IHC practice. Recheck for granular cytoplasmic hepatocyte staining (HPA: liver profile). |
| Most cells show broad brown staining, including a no-primary control. | Endogenous detection activity or reagent background is plausible when staining persists without primary antibody (standard chromogenic IHC practice). That result cannot be assigned to HAO1. | Check the detection-only control, endogenous-enzyme blocking, reagent compatibility and washes (standard IHC practice). Reassess specificity only after background is reduced and the expected liver pattern is visible (HPA: liver profile). |
| The primary-stained section is hazy, but the no-primary control is clean. | Nonspecific primary-antibody binding or insufficient washing is plausible (standard IHC practice). HPA also records presumed off-target staining in its tissue assessment (HPA: reliability description). | Review blocking, washes and primary-antibody concentration using the assay's validated range (standard IHC practice). Compare hepatocytes with a reported negative cell population before scoring faint diffuse signal as positive (HPA: positive and negative tissue IHC). |
| A crisp nuclear or membrane-like pattern dominates the liver section. | The compartment conflicts with granular cytoplasmic liver staining and peroxisome-matrix localisation (HPA: liver profile; UniProt Q9UJM8: subcellular location and topology). | Inspect morphology and controls, then compare the same cell types with an independently validated IHC antibody where available (HPA: HPA049552 and HPA072442, Enhanced IHC). Do not score the discordant compartment as the expected HAO1 pattern. |
| Adipocytes in adipose tissue stain strongly alongside hepatocytes. | That cell-type result conflicts with HPA's not-detected adipocyte observation; cross-reactivity or detection background needs investigation (HPA: adipocytes, Not detected; reliability description). | Check no-primary and tissue controls, compare staining patterns across sections, and reassess the primary antibody if the signal persists (standard IHC practice). Keep hepatocyte and adipocyte scores separate (HPA: cell-specific tissue IHC). |
| Keratinocytes stain in a section used as a presumed negative control. | Skin keratinocytes are not a clean negative reference: HPA reports medium staining (HPA: keratinocytes, Medium). | Choose a reported not-detected cell population, such as adipocytes in adipose tissue, for a biological negative comparison (HPA: adipocytes, Not detected). Interpret its staining with a no-primary control and the positive liver pattern (standard IHC practice; HPA: liver profile). |
Experiment evidence
IHC & IF images showing HAO1 staining
A09159-2 · IHCIHC analysis of HAO1 using anti-HAO1 antibody (A09159-2). HAO1 was detected in a paraffin-embedded section of mouse liver tissue. Heat media
A09159-2 · IHCIHC analysis of HAO1 using anti-HAO1 antibody (A09159-2). HAO1 was detected in a paraffin-embedded section of mouse liver tissue. Heat media
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000101323-HAO1/tissue/cerebral+cortex#imid_20901711
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000101323-HAO1/tissue/colon#imid_20901637
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000101323-HAO1/tissue/liver#imid_20901646
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000101323-HAO1/tissue/kidney#imid_20901647
HPA · ICC-IF U-251MGHuman Protein Atlas immunofluorescence, U-251MG, antibody HPA072442; green = HAO1, blue = nucleus, red = microtubules.
HPA · ICC-IF U-251MGHuman Protein Atlas immunofluorescence, U-251MG, antibody HPA072442; green = HAO1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for HAO1 IHC & IF
🧪Run liver first: hepatocytes should stain (HPA: High in hepatocytes). Use adipose tissue as the negative tissue, with adipocytes expected to show no detectable staining (HPA: Not detected in adipocytes); compare non-hepatocyte areas on the liver slide with background, without assuming those cells are validated negatives.
Positive control tissue: Liver (Hepatocytes, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show HAO1 in U-251MG, with annotated localisation: Vesicles (supported) (HPA subcellular).
Technical controls: Include a no-primary (secondary-only) slide, a concentration-matched rabbit IgG isotype control, and HAO1 knockout tissue or a validated peptide-block control (caption: rabbit anti-HAO1 antibody; standard IHC practice). Quench endogenous peroxidase in liver before HRP/DAB detection (caption: HRP/DAB; standard IHC practice).
⚠️Feasibility: A target-specific fixation window and fixation effect are unreported, and the selected paraffin-section caption does not state a fixative (caption: fixative not stated). The reported mouse-liver IHC used heat retrieval in EDTA at pH 8.0, so retrieval is a documented step, but its necessity has not been established by a comparison (caption: EDTA heat retrieval). No supplied comparison establishes whether frozen sections or IF are easier; for IF, check liver autofluorescence with an unstained control (standard IF practice).
HPA tissue IHC evidence for HAO1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — High consistency between antibody staining and RNA expression data. Presumed off target binding observed and disregarded.). 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 |
|---|---|---|---|---|
| Liver | Hepatocytes | High | Protein (IHC) | HPA → |
| Skin | Keratinocytes | 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 HAO1 IHC Tips
Troubleshoot HAO1 staining in paraffin sections by checking retrieval, granular cytoplasmic localisation, and cell specific controls before interpreting chromogenic signal.
How should I retrieve HAO1 in paraffin sections when staining is weak?
Start with heat mediated retrieval in EDTA at pH 8.0 for paraffin sections (datasheet A09159-2). The selected antibody stained mouse liver after that retrieval, followed by 10% goat serum blocking and 2 μg/ml primary antibody overnight at 4°C (datasheet A09159-2). If staining remains weak, check whether sections were fully deparaffinised and whether the retrieval bath maintained its intended temperature throughout the run (standard IHC practice). Compare any later retrieval adjustment on adjacent sections with the same detection conditions and a liver control, so increased background is not mistaken for recovered HAO1 (HPA: high in hepatocytes; standard IHC practice).
Could fixation explain weak or uneven HAO1 staining in my paraffin sections?
Target specific fixation sensitivity is unknown: the selected mouse liver caption identifies a paraffin section but does not state its fixative (datasheet A09159-2). Record the actual fixative and processing history for each specimen, then compare affected sections with a consistently processed liver control under the same EDTA pH 8.0 retrieval conditions (datasheet A09159-2; standard IHC practice). Uneven fixation or processing can produce uneven antigen access in paraffin sections, so inspect morphology and section integrity alongside staining (standard IHC practice). Do not assign a particular fixation effect to HAO1 from its liver expression, peroxisomal location, or reported modified residues alone (HPA: liver expression; UniProt Q9UJM8: peroxisome matrix and modified residues).
What staining pattern should I expect for HAO1 in liver IHC?
Expect granular cytoplasmic staining in liver, particularly in hepatocytes (HPA: granular cytoplasmic liver pattern and high hepatocyte staining). This is consistent with HAO1 residing in the peroxisome matrix, although chromogenic IHC cannot establish organelle identity from granules alone (UniProt Q9UJM8: peroxisome matrix; standard IHC interpretation). Review staining at the same magnification in the test and liver control sections, and score cytoplasmic signal separately from nuclear or diffuse extracellular colour (HPA: granular cytoplasmic liver pattern; standard IHC practice). If the dominant pattern is nuclear or confined to tissue edges, revisit retrieval, blocking, and detection before treating it as HAO1 (UniProt Q9UJM8: peroxisome matrix; standard IHC practice).
How should epitope uncertainty affect interpretation of HAO1 IHC?
The record lists 0 isoforms, a single 1–370 chain, and no transmembrane segment for HAO1 (UniProt Q9UJM8). Its reported modifications include succinyllysine at 184 and phosphoserines at 194 and 230, but the supplied evidence does not map this antibody's epitope (UniProt Q9UJM8; datasheet A09159-2). Therefore, do not explain a staining difference as isoform selection or modification dependent masking without direct epitope evidence (UniProt Q9UJM8; standard IHC interpretation). Keep retrieval and detection matched across sections, and use the documented liver staining pattern as a plausibility check rather than proof that every positive granule contains HAO1 (HPA: granular liver staining; standard IHC practice).
How can I check a granular HAO1 pattern by multiplex IF?
Use a validated hepatocyte marker alongside HAO1 when checking the cell type associated with liver signal (HPA: high HAO1 staining in hepatocytes; standard IF practice). Choose spectrally separated fluorophores and inspect an unstained liver section for autofluorescence before assigning weak puncta to either channel (standard IF practice). HAO1 is in the peroxisome matrix and has no transmembrane segment, so an intracellular epitope requires permeabilisation across cellular and peroxisomal membranes for IF access (UniProt Q9UJM8: matrix localisation and topology; standard IF practice). Compare each single stain with the multiplex image, and treat overlap as supportive spatial evidence rather than proof of molecular interaction (standard IF interpretation).
How do I distinguish HAO1 signal from chromogenic background?
The selected liver IHC used 10% goat serum blocking, a peroxidase conjugated secondary, and DAB development (datasheet A09159-2). Include a no primary control, check endogenous peroxidase blocking, and compare DAB development between test and control sections before attributing widespread brown colour to HAO1 (standard chromogenic IHC practice). HPA reports presumed off target binding that was disregarded when assessing its tissue staining, so a positive stain alone is insufficient to establish specificity (HPA: Enhanced reliability description). Prioritise granular cytoplasmic signal in hepatocytes; diffuse background, stained debris, and edge concentrated colour warrant a repeat with matched processing (HPA: liver pattern and hepatocyte staining; standard IHC practice).
How should I quantify HAO1 staining across liver sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the hepatocyte compartment before scoring, since HPA reports high hepatocyte staining and a granular cytoplasmic liver pattern (HPA: tissue IHC). For a chromogenic readout, record the percentage of positive hepatocytes and staining intensity, or calculate an H-score from intensity categories using the same thresholds for every section (standard IHC scoring practice). Normalise counts to the number of evaluable hepatocytes, or report positive cell density per mm² of viable tissue if area is the denominator (standard histology quantification practice). Exclude folds, necrosis, and tissue edges by a prespecified rule, and keep illumination and colour analysis settings fixed across slides (standard IHC quantification practice).
When should I doubt a positive HAO1 IHC result?
A credible liver result shows granular cytoplasmic staining in hepatocytes, consistent with HPA tissue observations and peroxisome matrix localisation (HPA: liver pattern and high hepatocyte staining; UniProt Q9UJM8). Question predominant nuclear, extracellular, or edge restricted colour, and inspect necrotic areas before calling them positive cells (UniProt Q9UJM8: matrix localisation; standard IHC interpretation). Compare with a no primary control because endogenous peroxidase and nonspecific detection can contribute DAB colour (standard chromogenic IHC practice). HPA also lists medium staining in skin keratinocytes, so staining outside liver should be judged against the documented cell type and pattern rather than dismissed solely by tissue name (HPA: medium in keratinocytes; standard IHC interpretation).
Boster reagents
Best HAO1 / 2-Hydroxyacid oxidase 1 IHC Antibodies
The catalog antibody A09159-2 has IHC images from paraffin-embedded human and mouse liver sections (catalog image captions). No IF image or IF dilution is supplied (catalog payload).
Real IHC data
Anti-HAO1 Antibody ®
Cat # A09159-2
A09159-2 is the sole SKU that will render; its IHC images show paraffin-embedded human and mouse liver sections (catalog image captions). Its listed applications include IHC, and its listed reactivity is human, mouse and rat (catalog applications and reactivity).
Which to pick: Choose A09159-2 for paraffin-section IHC; its own images show human and mouse liver sections, with the fixative unreported (A09159-2 image captions). No IF/ICC application or IF image is supplied for A09159-2, so this payload does not support an IF/ICC pick (catalog applications and image fields). For work across species, A09159-2 lists human, mouse and rat reactivity, while the supplied IHC images cover human and mouse only; clonality is unreported (catalog reactivity, image captions and clone field).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9UJM8 (HAOX1_HUMAN, 2-Hydroxyacid oxidase 1).
- Human Protein Atlas. HAO1 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. HAO1 subcellular location (ICC-IF): Localized to vesicles..
- Human Protein Atlas. HAO1 antibody validation summary (2 antibodies).
- Hydroxyacid Oxidase 1, a Glutamine Metabolism-Associated Protein, Predicts Poor Patient Outcome in Luminal Breast Cancer. International journal of molecular sciences 2024 — PMC11545845.
- HAO1-mediated oxalate metabolism promotes lung pre-metastatic niche formation by inducing neutrophil extracellular traps. Oncogene 2022 — PMC9287177.
- PubMed PMID:10978532 — UniProt-cited evidence.
- PubMed PMID:10777549 — UniProt-cited evidence.
- PubMed PMID:11780052 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for HAO1 (2-Hydroxyacid oxidase 1). Expected localisation Granular hepatocyte cytoplasm (HPA tissue IHC); peroxisomal matrix expected (UniProt). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A09159-2). Validated IHC antibody: A09159-2 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Liver (Hepatocytes); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded mouse liver tissue; fixative not specified (datasheet A09159-2); 2. Fixation: Image fixative and duration unreported (datasheet A09159-2); 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 A09159-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A09159-2); 8. Primary antibody: Rabbit anti-HAO1, 2-5 μg/ml (datasheet A09159-2); 9. Primary incubation: Overnight at 4 °C (datasheet A09159-2). Watch for: Fixation: Keep fixation consistent across sections. (standard IHC practice; not target-specific); Caveat: Presumed off-target staining was observed and disregarded (HPA tissue IHC); Isoform / epitope: No annotated isoforms; one chain spanning 1–370 (UniProt); Regulation: Liver-enriched expression (HPA tissue IHC). Evidence: UniProt Q9UJM8, HPA tissue IHC · Enhanced, HPA ICC-IF · vesicles., Datasheet A09159-2, PMC11545845. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/HAO1/immunohistochemistry-ihc-guide.