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STEAP1 / STEAP1 protein · IHC design guide
Design Immunohistochemistry for STEAP1
Plan chromogenic STEAP1 IHC on paraffin sections using the catalog antibody at 2.5 μg/mL (datasheet). Compare the observed cytoplasmic pattern with the reported tissue profile, while treating HPA staining as uncertain because presumed off-target binding awaits external verification (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
STEAP1 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 tissue (HPA tissue IHC); cell membrane and endosome membrane (UniProt) | |
| Staining pattern | Cytoplasmic in brain cells, pneumocytes and some prostate glandular cells (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| 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 sections (standard IHC practice; not target-specific) | |
| Caveat | Presumed off-target binding; external verification pending (HPA tissue IHC) | |
| Regulation | Highly expressed in prostate tumors (UniProt) | |
| Isoform / epitope | No annotated isoforms; extracellular vs cytoplasmic epitope affects access (UniProt) |
Section 1
Recommended STEAP1 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is accompanied by four published STEAP1 tissue IHC protocols (PMC4849046; PMC12710653; PMC9968870; PMC9643485).
| Sample | Tissue sections; selected-image fixative not specified (standard IHC workflow) |
| Fixation | Image fixative and duration unreported (datasheet A07506); 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-STEAP1, 2.5 μg/mL (datasheet A07506) |
| 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 | STEAP1-positive staining in cells in granular layer of cerebellum (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in brain, pneumocytes and subset of prostate glandular cells. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 retrieval at 95–98 °C for 20 min (page retrieval rule); published pressure-cooker conditions provide alternatives (PMC12710653; PMC9968870).
Section 2
What Is the Expected STEAP1 Staining Pattern?
STEAP1 is a six-pass protein assigned to the cell membrane and endosome membrane (UniProt Q9UHE8 topology and subcellular location). In paraffin-section IHC, HPA describes cytoplasmic staining in brain cells, pneumocytes and a subset of prostate glandular cells (HPA tissue IHC). Treat that distribution as provisional: HPA rates its tissue staining Uncertain because presumed off-target binding was observed and disregarded, with external verification pending (HPA tissue IHC).
| A subset of prostate glandular cells shows cytoplasmic staining of moderate intensity. | This matches the reported prostate pattern (HPA tissue IHC: Medium in glandular cells). A membrane-associated or punctate component is biologically plausible from STEAP1's cell membrane and endosome locations, but HPA's observed IHC profile is cytoplasmic and Uncertain (UniProt Q9UHE8 subcellular location; HPA tissue IHC). |
| Alveolar cells or the listed neuronal populations show stronger cytoplasmic staining. | High staining is reported in lung alveolar cells, hippocampal neurons and cerebellar granular-layer cells (HPA tissue IHC). These are provisional comparison patterns, not independently verified positive controls, because the tissue IHC reliability is Uncertain (HPA tissue IHC). |
| Strong nuclear staining dominates, with little staining in the expected cytoplasmic or membrane-associated pattern. | Nuclear dominance does not fit the reported cell membrane and endosome locations or HPA's cytoplasmic IHC profile (UniProt Q9UHE8 subcellular location; HPA tissue IHC). Examine the negative control and staining conditions before interpreting it as STEAP1. |
| Prominent staining appears in bronchial respiratory epithelial cells or appendix glandular cells. | HPA reports STEAP1 as Not detected in those specific cell populations (HPA tissue IHC). Consider nonspecific antibody binding or endogenous detection activity; HPA's Uncertain reliability means an unexpected signal needs independent confirmation, not an automatic exclusion (HPA tissue IHC; general IHC practice). |
| Diffuse color covers tissue and spaces between cells, obscuring cell boundaries. | A widespread deposit cannot be assigned confidently to HPA's reported cell populations (HPA tissue IHC). Review the negative control, detection background, washes and blocking before scoring; diffuse background alone does not establish STEAP1 expression (general IHC practice). |
💡Expected STEAP1 appearanceCall a result provisionally positive when staining is cell-associated and predominantly cytoplasmic in the reported cells, such as moderately stained prostate glandular cells; strong nuclear-only or widespread acellular color is suspect (HPA tissue IHC: Medium in prostate glandular cells, reliability Uncertain; UniProt Q9UHE8 subcellular location).
| Membrane topology and compartment | STEAP1 has 6 transmembrane segments and is assigned to cell and endosome membranes (UniProt Q9UHE8 topology and subcellular location). HPA describes the tissue IHC appearance as cytoplasmic; do not require a sharp surface-only outline to recognize its reported pattern (HPA tissue IHC). |
| Tissue and cell selection | HPA reports Medium staining in prostate glandular cells and High staining in lung alveolar cells, hippocampal neurons and cerebellar granular-layer cells (HPA tissue IHC). Compare the named cell populations rather than whole-section color; all these IHC observations carry HPA's Uncertain reliability (HPA tissue IHC). |
| Antibody-validation limit | The listed antibody, HPA030985, has an Uncertain IHC status, and the tissue profile is pending external verification (HPA antibodies; HPA tissue IHC). Reproducible location and cell-type agreement strengthen an interpretation, but these records alone do not establish IHC specificity. |
| Protein processing and target form | The supplied UniProt record lists one chain spanning residues 1–339, with no signal peptide, propeptide, glycosylation sites or isoforms (UniProt Q9UHE8 processing, glycosylation and isoforms). These annotations give no basis for assigning a distinct staining pattern to a shed or alternative form. |
| IF/ICC: what pattern can be expected? | A membrane-associated signal is consistent with UniProt's cell membrane and endosome assignments, and HPA summarizes its subcellular location as Membrane (UniProt Q9UHE8 subcellular location; HPA subcellular). HPA supplies no ICC-IF image cell lines or main-location detail here, so this record cannot establish an IF cell-type pattern (HPA subcellular). |
| Situation | Likely cause | Next action |
|---|---|---|
| No staining in prostate glandular cells. | The reported prostate signal is only Medium and present in a subset of glandular cells; absence in one field may reflect cell selection or assay sensitivity (HPA tissue IHC). | Check that the relevant glands are present, review a negative control, and optimize the catalog antibody's documented IHC-P conditions if available; record any departure from those conditions (general IHC practice). |
| No staining in a proposed high-signal comparison tissue. | HPA reports High staining in specific alveolar or neuronal cell populations, but rates the tissue pattern Uncertain (HPA tissue IHC). A negative result alone cannot identify the failed step. | Confirm the named cells are present and inspect the detection control. Reassess antigen retrieval and primary-antibody conditions against the antibody's IHC-P instructions, without assuming a STEAP1-specific fixation effect (general IHC practice). |
| Nuclear staining dominates. | The compartment conflicts with the reported cytoplasmic IHC profile and UniProt's membrane assignments (HPA tissue IHC; UniProt Q9UHE8 subcellular location). | Compare with a no-primary control and review antibody dilution and detection background. Score nuclear-only signal separately until an independent method supports its identity (general IHC practice). |
| Many unexpected cell types stain. | Broad staining may reflect cross-reactivity or endogenous detection activity (general IHC practice). HPA also reports presumed off-target binding and Uncertain tissue reliability (HPA tissue IHC). | Check controls and the cell-specific HPA comparisons, including Not detected bronchial respiratory epithelial and appendix glandular cells (HPA tissue IHC). Confirm unexpected staining with an independent approach before assigning it to STEAP1. |
| Diffuse brown background obscures cellular staining. | Nonspecific binding, insufficient washing or endogenous enzyme activity can produce diffuse chromogenic background (general IHC practice). The appearance cannot be matched reliably to HPA's named positive cells. | Inspect no-primary and detection controls, then review blocking, washes and endogenous-activity blocking appropriate to the chromogen system (general IHC practice). Re-score only cell-associated signal after background is controlled. |
| Results vary between sections or staining runs. | Differences in retrieval, antibody concentration, detection or cell composition can change IHC appearance (general IHC practice); the supplied records do not establish STEAP1-specific fixation sensitivity. | Run comparable sections and controls together, document retrieval and antibody conditions, and score the same named cell population each time (general IHC practice; HPA tissue IHC). Keep the HPA Uncertain designation in the interpretation (HPA tissue IHC). |
Experiment evidence
IHC & IF images showing STEAP1 staining
A07506 · IHCImmunohistochemistry of STEAP1 in human spleen tissue with STEAP1 antibody at 2.5 μg/mL.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000164647-STEAP1/tissue/cerebral+cortex#imid_15213506
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000164647-STEAP1/tissue/colon#imid_15213448
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000164647-STEAP1/tissue/liver#imid_15213441
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000164647-STEAP1/tissue/kidney#imid_15213450
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for STEAP1 IHC & IF
🧪Run cerebellum first: cells in the granular layer should stain (HPA: High in cerebellar granular-layer cells). Use adipose tissue as the negative tissue; adipocytes should remain unstained (HPA: Not detected in adipocytes).
Positive control tissue: Cerebellum (Cells in granular layer, 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 STEAP1; derive a cell-line control from the positive tissue's cell type (Cells in granular layer) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary (secondary-only) control, a host-matched irrelevant monoclonal IgG or nonimmune polyclonal IgG control as appropriate, and STEAP1-knockout tissue or validated peptide competition (standard IHC practice). For chromogenic cerebellar IHC, quench endogenous peroxidase and compare background with the no-primary slide (standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the A07506 spleen IHC caption does not state a fixative (selected IHC caption). Retrieval dependence is unreported; compare retrieval conditions during paraffin-section optimization (standard IHC practice). The supplied evidence does not establish that frozen sections or IF are easier; in the densely packed cerebellar granular layer, assess staining cell by cell against the no-primary section (standard histology and IHC practice).
HPA tissue IHC evidence for STEAP1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Uncertain — Presumed off target binding observed and disregarded. 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 |
|---|---|---|---|---|
| Cerebellum | Cells in granular layer | High | Protein (IHC) | HPA → |
| Hippocampus | Neuronal cells | High | Protein (IHC) | HPA → |
| Lung | Alveolar cells | High | Protein (IHC) | HPA → |
| Cerebral cortex | Neuronal cells | Medium | Protein (IHC) | HPA → |
| Prostate | Glandular cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced STEAP1 IHC Tips
Troubleshoot STEAP1 staining in paraffin sections using membrane and endosome localisation, the selected antibody image, and cautious interpretation of tissue patterns.
How should I retrieve STEAP1 in paraffin sections when staining is weak?
Start with citrate buffer at pH 6.0, heated to 95–98 °C for 20 min (page retrieval rule). Cool sections consistently before antibody incubation, and keep the chromogenic detection steps identical across test sections so retrieval is the variable being assessed (standard IHC practice). STEAP1 has six transmembrane segments and localises to cell and endosome membranes, making compartment specific staining a useful check alongside signal intensity (UniProt Q9UHE8 topology and localisation). If staining remains weak, test a different retrieval buffer or pH on adjacent sections, then compare signal with background and a no primary control (standard IHC practice).
How can I assess whether fixation is limiting STEAP1 staining?
STEAP1 specific sensitivity to fixation is unknown from the supplied evidence, and the selected tissue image does not state its fixative (A07506 caption). For paraffin IHC, record fixative, fixation duration, block age, and processing history before comparing sections, because these variables can change antigen accessibility (standard IHC practice). Apply the same citrate pH 6.0, 95–98 °C, 20 min retrieval and the same antibody detection conditions to sections from each block (page retrieval rule; standard IHC practice). Judge any suspected fixation effect against tissue preservation, background, and compartment appropriate staining, rather than attributing a weak result to fixation from a single section (standard IHC practice; UniProt Q9UHE8 localisation).
Where should convincing STEAP1 chromogenic staining appear?
STEAP1 is annotated at the cell membrane and endosome membrane, with six transmembrane segments (UniProt Q9UHE8 localisation and topology). In chromogenic sections, assess membrane outlining and intracellular punctate staining in morphologically identified cells, while recognising that section thickness and chromogen deposition can obscure fine membrane boundaries (UniProt Q9UHE8 localisation; standard IHC practice). HPA describes cytoplasmic staining in brain cells, pneumocytes, and a subset of prostate glandular cells, but rates its tissue IHC reliability uncertain because presumed off target binding was observed (HPA tissue IHC). Compare the distribution with a no primary control and consistent counterstaining before assigning diffuse cytoplasmic signal to STEAP1 (standard IHC practice).
What should I check if STEAP1 staining depends strongly on antibody choice?
The supplied record lists 0 isoforms and 0 glycosylation sites, so neither an annotated isoform switch nor an annotated glycosylation site explains a staining difference here (UniProt Q9UHE8 record). STEAP1 contains six transmembrane segments; compare each antibody’s disclosed immunogen with the protein sequence and predicted membrane topology before interpreting discordant patterns (UniProt Q9UHE8 topology; standard IHC practice). An epitope within a membrane embedded region may be less accessible in a processed section, but accessibility for any particular antibody remains unestablished without its epitope information (standard IHC practice). Titrate antibodies on adjacent sections under matched retrieval and detection conditions, and require plausible localisation with controlled background (UniProt Q9UHE8 localisation; standard IHC practice).
How can IF help assess a questionable STEAP1 IHC pattern?
Use IF as a separate validation experiment: pair STEAP1 with a marker for the expected cell type, such as a glandular cell marker when examining prostate glandular cells (HPA tissue IHC; standard IF practice). Select spectrally separated fluorophores and place the weaker signal in a channel with low tissue autofluorescence, checking unstained tissue and single stain controls first (standard IF practice). Because STEAP1 occupies cell and endosome membranes, choose permeabilisation according to whether the antibody recognises an extracellular or intracellular epitope, and verify that choice against the antibody’s epitope information (UniProt Q9UHE8 localisation and topology; standard IF practice). Compare cellular overlap and compartment distribution with the chromogenic pattern while keeping the HPA tissue IHC uncertainty in view (HPA tissue IHC; standard IF practice).
What controls help distinguish STEAP1 signal from chromogenic background?
Run a no primary control through the same secondary reagent, peroxidase block, chromogen, and counterstain steps to locate detection background (standard IHC practice). Check for endogenous peroxidase activity before interpreting DAB deposits, and compare antibody titrations against the selected antibody’s spleen image concentration of 2.5 µg/mL as an image reference, not a universal working concentration (standard IHC practice; A07506 caption). The HPA tissue IHC assessment reports presumed off target binding and uncertain reliability, so visually strong staining alone does not establish specificity (HPA tissue IHC). Inspect folds, section edges, and damaged tissue separately from intact cells, then retain conditions that preserve plausible membrane or endosome associated staining with low control signal (standard IHC practice; UniProt Q9UHE8 localisation).
How should I quantify STEAP1 staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the eligible cell population and compartment before scoring, using the same morphology rules and chromogen threshold across sections (standard IHC practice; UniProt Q9UHE8 localisation). Report the percentage of positive cells with an intensity based H-score, or measure positive cell density per mm² of viable tissue when cell counts are the comparison of interest (standard IHC practice). Normalise the numerator to the counted eligible cells or measured viable tissue area, and exclude necrosis, folds, and blank space from that denominator (standard IHC practice). Score membrane associated and cytoplasmic patterns separately, and label HPA tissue patterns as uncertain supporting context rather than a scoring standard (UniProt Q9UHE8 localisation; HPA tissue IHC).
When is a positive STEAP1 IHC result credible?
A credible result shows reproducible staining in morphologically identified cells, with membrane associated or plausible endosome associated distribution and little signal in the no primary control (UniProt Q9UHE8 localisation; standard IHC practice). Evaluate cell identity explicitly: HPA reports staining in prostate glandular cells, pneumocytes, and brain cells, while warning that its tissue IHC reliability is uncertain because presumed off target binding was observed (HPA tissue IHC). Treat isolated nuclear staining, edge concentrated deposits, necrotic material, or residual endogenous enzyme signal as reasons to investigate an artefact before scoring (UniProt Q9UHE8 localisation; standard IHC practice). Confirm the pattern across intact regions and adjacent sections under matched retrieval and detection conditions before drawing a tissue level conclusion (standard IHC practice).
Boster reagents
Best STEAP1 / STEAP1 protein IHC Antibodies
One anti-STEAP1 antibody has a human spleen IHC figure; its catalog lists human, mouse and rat reactivity, with no IF/ICC data (A07506 image caption; catalog: applications/reactivity).
Real IHC data
Anti-Metalloreductase STEAP1 STEAP1 Antibody
Cat # A07506
A07506 is listed for IHC-P and for human, mouse and rat reactivity (catalog: A07506 applications/reactivity). Its own figure shows human spleen IHC at 2.5 μg/mL; no IF/ICC figure is provided (A07506 image caption; catalog: IF images).
Which to pick: Choose A07506 for paraffin-section tissue IHC: IHC-P is listed, and its own figure shows human spleen staining at 2.5 μg/mL (catalog: A07506 applications; A07506 image caption). The figure does not report a fixative, and no clone is specified (A07506 image caption; catalog: clone). For IF/ICC, no validated SKU is listed; for cross-species work, A07506 lists human, mouse and rat reactivity, but its reported IHC validation is in human samples only (catalog: A07506 applications/reactivity; datasheet: human IHC validation).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9UHE8 (STEA1_HUMAN, STEAP1 protein).
- Human Protein Atlas. STEAP1 tissue IHC expression (reliability: Uncertain).
- Human Protein Atlas. STEAP1 subcellular location (ICC-IF): Membrane.
- Human Protein Atlas. STEAP1 antibody validation summary (1 antibodies).
- The Prognostic Role of STEAP1 Expression Determined via Immunohistochemistry Staining in Predicting Prognosis of Primary Colorectal Cancer: A Survival Analysis. International journal of molecular sciences 2016 — PMC4849046.
- Armoring STEAP1 CAR T cells with IL-18 potentiates antitumor activity in Ewing sarcoma. bioRxiv : the preprint server for biology 2025 — PMC12710653.
- Prognostic Significance of Iron Metabolism Related Genes in Human Lung Adenocarcinoma. Cancer management and research 2023 — PMC9968870.
- EFEMP1 binds to STEAP1 to promote osteosarcoma proliferation and invasion via the Wnt/β-catenin and TGF-β/Smad2/3 signal pathways. Journal of bone oncology 2022 — PMC9643485.
- PubMed PMID:10588738 — UniProt-cited evidence.
- PubMed PMID:12853948 — UniProt-cited evidence.
- PubMed PMID:12690205 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for STEAP1 (STEAP1 protein). Expected localisation Cytoplasmic in tissue (HPA tissue IHC); cell membrane and endosome membrane (UniProt). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A07506 at 2.5 μg/mL (the product's own IHC validation image is shown). Controls (HPA): positive Cerebellum (Cells in granular layer); negative Adipose tissue. 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 A07506); 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-STEAP1, 2.5 μg/mL (datasheet A07506); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Caveat: Presumed off-target binding; external verification pending (HPA tissue IHC); Isoform / epitope: No annotated isoforms; extracellular vs cytoplasmic epitope affects access (UniProt); Regulation: Highly expressed in prostate tumors (UniProt). Evidence: UniProt Q9UHE8, HPA tissue IHC · Uncertain, HPA ICC-IF · Membrane, Datasheet A07506, PMC4849046, PMC12710653. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/STEAP1/immunohistochemistry-ihc-guide.