This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
CYP1A1 / Cytochrome P450 1A1 · IHC design guide
Design Immunohistochemistry for CYP1A1
Plan chromogenic CYP1A1 IHC in paraffin sections using the catalog antibody’s IHC-P conditions (datasheet PB9544). Compare cytoplasmic staining with tissue controls and interpret results in light of the uncertain tissue-IHC reliability (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
CYP1A1 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 tissue stain (HPA tissue IHC); ER and mitochondrial localization (UniProt) | |
| Staining pattern | General cytoplasmic staining, including glandular cells (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6 HIER, heat-mediated (datasheet PB9544) | |
| Positive control | Adrenal gland+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 paraffin sections (standard IHC practice; not target-specific) | |
| Caveat | Tissue staining has very low agreement with RNA data (HPA tissue IHC) | |
| Regulation | Expression regulation is not specified (UniProt) | |
| Isoform / epitope | 3 isoforms; epitope coverage needs validation (UniProt) |
Section 1
Recommended CYP1A1 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is followed by published protocols for fish tissues, mouse lung, and human skin (PMC11544920; PMC4201582; PMC8082009).
| Sample | Paraffin-embedded Mouse Kidney tissue; fixative not specified (datasheet PB9544) |
| Fixation | Image fixative and duration unreported (datasheet PB9544); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Citrate pH 6, 20 min (datasheet PB9544) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet PB9544) |
| Primary antibody | Rabbit anti-CYP1A1, 0.5-1μg/ml (datasheet PB9544) |
| Primary incubation | Overnight at 4 °C (datasheet PB9544) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet PB9544) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | CYP1A1-positive staining in glandular cells of adrenal gland (HPA tissue IHC: Medium). HPA tissue profile: General cytoplasmic expression. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated citrate retrieval at pH 6, as specified for the catalog antibody (datasheet PB9544).
Section 2
What Is the Expected CYP1A1 Staining Pattern?
CYP1A1 is annotated at endoplasmic reticulum, microsomal and mitochondrial inner membranes, and in cytoplasm; UniProt annotates no transmembrane segment (UniProt P04798: subcellular location and topology). In paraffin-section IHC, expect predominantly cytoplasmic staining in selected epithelial and glandular cells (HPA: general cytoplasmic profile). Treat that expectation cautiously: the tissue IHC result is Uncertain because antibody staining has very low consistency with RNA expression and awaits external verification (HPA: tissue IHC reliability).
| Cytoplasmic stain in bronchial respiratory epithelium or glandular cells of appendix, colon or duodenum. | This matches cell types reported at Medium intensity (HPA: tissue IHC). Assess the cells and compartment together; a matching pattern supports interpretation but does not establish antibody specificity because the IHC reliability is Uncertain (HPA: reliability). |
| Predominantly nuclear stain, with little cytoplasmic signal. | A nucleus-dominant pattern conflicts with the reported general cytoplasmic IHC profile and UniProt localization (HPA: tissue IHC; UniProt P04798: subcellular location). Review counterstain, detection background and antibody controls before scoring it as CYP1A1 (general IHC practice). |
| Strong stain in adipocytes or skeletal-muscle myocytes while candidate positive cells remain weak. | Those cell types are reported Not detected (HPA: adipose tissue and skeletal muscle IHC). Consider cross-reactivity or endogenous detection activity; the slide alone cannot distinguish them (general IHC practice). |
| Diffuse chromogen across cells, stroma and slide background without cell boundaries. | This is less interpretable than the reported cellular cytoplasmic profile (HPA: tissue IHC). Check background in a no-primary control and review blocking, washing and detection conditions before assigning a tissue score (general IHC practice). |
| No stain in bronchial respiratory epithelium or reported Medium glandular cells. | The absence differs from the sampled HPA observations (HPA: bronchus, appendix, colon and duodenum IHC). Review section quality, retrieval and reagent performance with controls; the Uncertain HPA reliability means these tissues are candidate comparators, not guaranteed positives (HPA: reliability; general IHC practice). |
💡Expected CYP1A1 appearanceCall a plausible positive when selected respiratory epithelial or glandular cells show cytoplasmic staining near the reported Medium level; isolated nuclear stain or widespread cell-independent color warrants review (HPA: tissue IHC; UniProt P04798: subcellular location; general IHC practice).
| Compartment and topology | UniProt places CYP1A1 at endoplasmic reticulum, microsomal and mitochondrial inner membranes and in cytoplasm, without an annotated transmembrane segment (UniProt P04798: subcellular location and topology). Routine chromogenic IHC may not resolve those structures separately (general IHC practice). |
| Tissue evidence and validation | HPA reports Medium staining in specified epithelial and glandular cells, but rates tissue IHC Uncertain; the listed antibody, CAB018654, is also IHC Uncertain (HPA: tissue IHC and antibody validation). Use patterns as provisional comparators. |
| Isoforms and epitope coverage | Three isoforms are listed (UniProt P04798: isoforms 1–3). Their relative staining cannot be inferred without antibody epitope information; avoid assigning a difference in intensity to a particular isoform (general IHC interpretation). |
| IF/ICC Q: What localization can guide image review? | A: Membrane-associated or cytoplasmic signal is plausible (UniProt P04798: subcellular location; HPA: general cytoplasmic tissue profile). HPA summarizes subcellular localization as Membrane but supplies no ICC-IF images or main location, and the listed antibody has no ICC validation status (HPA: subcellular and antibody records). |
| Situation | Likely cause | Next action |
|---|---|---|
| Weak or absent stain in a candidate positive section. | The section may have a workflow or reagent problem; HPA's Medium observations are uncertain comparators (HPA: tissue IHC reliability; general IHC practice). | Review tissue preservation, retrieval conditions, antibody incubation and detection controls; compare with another reported Medium cell population when available (HPA: tissue IHC; general IHC practice). |
| Nucleus dominates the signal. | That compartment differs from the HPA cytoplasmic profile and UniProt locations (HPA: tissue IHC; UniProt P04798: subcellular location). | Check nuclear counterstain and a no-primary control; reassess localization before recording a positive cell score (general IHC practice). |
| Adipocytes, myocytes or fibroblasts stain prominently. | HPA reports these cells as Not detected in adipose tissue, skeletal muscle and soft tissue, respectively (HPA: tissue IHC). | Compare cellular stain with no-primary and detection controls; investigate nonspecific binding or endogenous detection activity before interpreting it as CYP1A1 (general IHC practice). |
| Background obscures the cytoplasmic pattern. | Noncellular color can reflect nonspecific binding or detection background (general IHC practice). | Inspect a no-primary control, then review blocking, wash steps and detection conditions using the same tissue and scoring criteria (general IHC practice). |
| Two reported Medium tissues stain differently. | HPA tissue staining has very low consistency with RNA expression, so apparent tissue agreement is uncertain (HPA: tissue IHC reliability). | Record the cell type, compartment and intensity for each section; repeat with suitable controls before treating the difference as biological (general IHC practice). |
| IF/ICC signal disagrees with the paraffin-section IHC pattern. | The HPA subcellular entry has no ICC-IF images or main location, and CAB018654 has no ICC validation status (HPA: subcellular and antibody records). | Interpret IF/ICC on its separate guide page; compare compartments cautiously with UniProt locations and do not use this IHC pattern alone to validate an IF result (UniProt P04798: subcellular location; general IHC/IF practice). |
Experiment evidence
IHC & IF images showing CYP1A1 staining
PB9544 · IHCIHC analysis of CYP1A1 using anti-CYP1A1 antibody (PB9544). CYP1A1 was detected in frozen section of Human Placenta Tissue. The tissue secti
PB9544 · IHCIHC analysis of CYP1A1 using anti-CYP1A1 antibody (PB9544). CYP1A1 was detected in paraffin-embedded section of Mouse Kidney Tissue. Heat me
PB9544 · IFIF analysis of CYP1A1 using anti-CYP1A1 antibody (PB9544). CYP1A1 was detected in immunocytochemical section of Caco-2 cells. Enzyme antigen
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000140465-CYP1A1/tissue/cerebral+cortex#imid_4805308
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000140465-CYP1A1/tissue/colon#imid_4805226
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000140465-CYP1A1/tissue/liver#imid_4805227
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000140465-CYP1A1/tissue/kidney#imid_4805220
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for CYP1A1 IHC & IF
🧪Run bronchus first: respiratory epithelial cells should stain at the HPA Medium level (HPA: Bronchus, respiratory epithelial cells, Medium). Use adipose tissue as the negative comparator, where adipocytes are not detected (HPA: Adipose tissue, adipocytes, Not detected); on the bronchus slide, assess cells without epithelial labeling as an internal background reference rather than assuming every neighboring cell is negative.
Positive control tissue: Adrenal gland (Glandular cells, HPA Medium)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for CYP1A1; derive a cell-line control from the positive tissue's cell type (Glandular cells) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only control and a rabbit immunoglobulin-class-matched isotype control at the primary antibody concentration (caption: rabbit anti-CYP1A1 antibody); use CYP1A1 knockout material or a cognate-peptide block, if available, to test target specificity (standard IHC practice). Check endogenous peroxidase and biotin background because the supplied detection uses a biotinylated secondary, streptavidin–biotin complex and DAB (caption: PB9544 detection).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected paraffin-section caption does not state the fixative (caption: fixative not stated). The caption provides a practical IHC retrieval starting point of citrate buffer at pH 6 for 20 minutes, but does not establish that retrieval is required across preparations (caption: PB9544). There is no supplied basis to call frozen sections or IF easier; assess chromogenic background in bronchus with the detection controls before scoring epithelial staining (caption: biotin–DAB detection; HPA: Bronchus, respiratory epithelial cells, Medium).
HPA tissue IHC evidence for CYP1A1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Uncertain — Very low consistency between antibody staining and RNA expression data. 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 |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | Medium | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Medium | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Medium | Protein (IHC) | HPA → |
| Cerebellum | Purkinje cells | Medium | Protein (IHC) | HPA → |
| Colon | 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 → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
| Skeletal muscle | Myocytes | Not detected | Protein (IHC) | HPA → |
| Smooth muscle | Smooth muscle cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced CYP1A1 IHC Tips
Troubleshoot CYP1A1 chromogenic IHC in paraffin sections by checking retrieval, staining distribution, controls, and scoring before interpreting biological differences.
How should I adjust retrieval when CYP1A1 staining is weak in paraffin sections?
Start with heat-mediated citrate retrieval at pH 6 for 20 minutes in paraffin sections (datasheet PB9544: mouse kidney IHC caption). The caption used 1 μg/mL primary antibody overnight at 4°C; keep that reference setup while comparing retrieval with a matched section processed without retrieval (datasheet PB9544; standard IHC practice). If staining remains weak, test a longer heating period or an alternative buffer on serial sections, recording signal, background, and tissue integrity before adopting the change (standard IHC practice). The caption does not report a fixative, so its retrieval result cannot establish performance across fixation conditions (datasheet PB9544).
Could fixation explain inconsistent CYP1A1 staining between paraffin specimens?
Target-specific fixation sensitivity is unknown: the selected paraffin-section caption does not state a fixative, and no CYP1A1 fixation comparison is supplied (datasheet PB9544). Record each specimen’s fixative, time to fixation, fixation duration, and processing history, then compare sections processed together with the same retrieval and detection reagents (standard IHC practice). When fixation histories differ, compare tissue morphology and staining in matched cell populations before attributing intensity differences to CYP1A1 abundance (standard IHC practice). Do not infer fixation tolerance from reported tissue staining patterns or CYP1A1 topology; neither measures the effect of a fixative on this antibody (HPA: tissue IHC profile; UniProt P04798 topology).
Where should CYP1A1 signal appear, and when is its distribution suspicious?
Assess CYP1A1 primarily as a cytoplasmic or membrane-associated signal, with possible endoplasmic reticulum, microsomal, and mitochondrial distributions (UniProt P04798 localisation; HPA: general cytoplasmic expression). The record reports no transmembrane segment, so a sharp outline of the cell surface alone deserves scrutiny rather than automatic acceptance as target staining (UniProt P04798 topology; standard IHC practice). Compare the pattern with cellular morphology on the counterstained section and with a no-primary control, especially where pigment or edge staining complicates reading (standard IHC practice). Treat HPA staining as supporting context only because its tissue IHC reliability is rated uncertain (HPA: reliability Uncertain).
How can I distinguish epitope masking from isoform-dependent CYP1A1 staining?
CYP1A1 has 3 listed isoforms, but the supplied record does not map this antibody’s epitope to any of them (UniProt P04798: isoforms; datasheet PB9544: epitope not stated). A glycosylation site is annotated at residue 67; without an epitope map, do not assign weak staining to glycosylation or assume equal recognition of every isoform (UniProt P04798: glycosylation; standard IHC interpretation). Compare serial sections across retrieval conditions while holding antibody concentration and detection constant, then check whether morphology and background change alongside signal (standard IHC practice). For an isoform-specific conclusion, obtain epitope or sequence evidence and orthogonal validation rather than relying on chromogenic intensity alone (standard IHC practice).
How should an IF follow-up test a CYP1A1 IHC pattern?
Use IF as a separate validation experiment and multiplex CYP1A1 with a validated marker for the cell population being assessed; respiratory epithelial cells are one reported context for CYP1A1 staining (HPA: bronchus respiratory epithelial cells, Medium; standard IF practice). Choose spectrally separated fluorophores, favoring a far-red CYP1A1 channel when tissue autofluorescence obscures shorter wavelengths, and include single-label and no-primary controls (standard IF practice). CYP1A1 has reported endoplasmic reticulum and mitochondrial membrane localisation, but the antibody epitope’s membrane-facing side is not supplied (UniProt P04798 localisation; datasheet PB9544: epitope not stated). Titrate permeabilisation against morphology and marker retention rather than presuming that the paraffin IHC retrieval conditions transfer to IF (standard IF practice).
What should I check when DAB obscures CYP1A1 staining?
First compare a no-primary section with the test section to separate detection-system staining from primary-dependent signal (standard IHC practice). The selected caption used a biotinylated secondary, streptavidin-biotin complex, and DAB; evaluate endogenous biotin and include a peroxidase block as general controls for that chromogenic workflow (datasheet PB9544; standard IHC practice). If diffuse color persists, review serum blocking, washing, antibody concentration, and development time on matched sections before increasing contrast or changing the score threshold (standard IHC practice). Read suspicious deposits against the counterstain and tissue morphology, because folds, edges, and pigment can imitate localized signal (standard IHC practice).
How should I score CYP1A1 IHC across specimens with different cell composition? ⚠ ANSWER MARKED FOR VERIFICATION
Define the compartment and cell population before scoring, then apply identical illumination, DAB development, and positivity thresholds across specimens (standard IHC practice). For cellular staining, report the percentage of positive cells and an H-score from 0–300, calculated from the percentages at intensity scores 0–3; document the scoring rubric (standard IHC practice). Normalize each result to the number of evaluable cells in the specified population, or report positive-cell density per mm² of viable annotated tissue when area is the denominator (standard IHC practice). Keep cell types separate because variable tissue composition can change an aggregate score without a change within the cells of interest (standard IHC practice).
When does a positive CYP1A1 stain support a biological conclusion?
A credible positive should recur in comparable cells and show a plausible cytoplasmic or membrane-associated distribution, rather than only a nuclear or cell-edge pattern (UniProt P04798 localisation; HPA: general cytoplasmic expression; standard IHC practice). Inspect tissue edges, folds, necrotic regions, and the no-primary control before accepting focal DAB as CYP1A1; endogenous peroxidase can also produce chromogenic background (standard IHC practice). Cell identity matters: respiratory epithelial staining has been reported, whereas some other listed cell populations were not detected in the HPA tissue survey (HPA: tissue IHC profile). Because that survey is rated uncertain, confirm a consequential pattern with independent biological evidence before interpreting differences as CYP1A1 regulation (HPA: reliability Uncertain; standard IHC practice).
Boster reagents
Best CYP1A1 / Cytochrome P450 1A1 IHC Antibodies
PB9544 has real IHC images from human, mouse and rat tissue sections, plus IF data from Caco-2 cells (catalog image captions).
Real IHC data
Anti-Cytochrome P450 1A1/CYP1A1 Antibody ®
Cat # PB9544
PB9544 is listed for IHC and IF/ICC in human, mouse and rat (catalog applications and reactivity). Its IHC images show human mammary cancer, mouse kidney and rat kidney paraffin sections and a human placenta frozen section; its IF image shows Caco-2 cells (catalog image captions).
Which to pick: Choose PB9544 for paraffin-section IHC: its own captions show staining in human mammary cancer, mouse kidney and rat kidney after citrate retrieval (PB9544 IHC image captions). For IF/ICC, PB9544 has a Caco-2 cell image and a listed starting concentration of 2 μg/mL (PB9544 IF image caption; catalog dilution). PB9544 is listed as human, mouse and rat reactive and has a rabbit host; clonality and the fixative used for its paraffin sections are unreported (catalog reactivity and host; PB9544 IHC image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P04798 (CP1A1_HUMAN, Cytochrome P450 1A1).
- Human Protein Atlas. CYP1A1 tissue IHC expression (reliability: Uncertain).
- Human Protein Atlas. CYP1A1 subcellular location (ICC-IF): Membrane.
- Human Protein Atlas. CYP1A1 antibody validation summary (1 antibodies).
- Systemic effects of arctic pollutants in beluga whales indicated by CYP1A1 expression. Environmental health perspectives 2005 — PMC1310924.
- Pathological Changes and CYP1A1 Expression as Biomarkers of Pollution in Sarpa Salpa and Diplodus Sargus. Animals : an open access journal from MDPI 2024 — PMC11544920.
- Sex-specific differences in hyperoxic lung injury in mice: implications for acute and chronic lung disease in humans. Toxicology and applied pharmacology 2013 — PMC4201582.
- Aryl Hydrocarbon Receptor and Autophagy-Related Protein Microtubule-Associated Protein Light Chain 3 Expression in Psoriasis. Annals of dermatology 2021 — PMC8082009.
- PubMed PMID:2989797 — UniProt-cited evidence.
- PubMed PMID:3838385 — UniProt-cited evidence.
- PubMed PMID:3019683 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for CYP1A1 (Cytochrome P450 1A1). Expected localisation Cytoplasmic tissue stain (HPA tissue IHC); ER and mitochondrial localization (UniProt). Antigen retrieval: Citrate pH 6 HIER, heat-mediated (datasheet PB9544). Validated IHC antibody: PB9544 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded Mouse Kidney tissue; fixative not specified (datasheet PB9544); 2. Fixation: Image fixative and duration unreported (datasheet PB9544); 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: Citrate pH 6 , 20 min (datasheet PB9544); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet PB9544); 8. Primary antibody: Rabbit anti-CYP1A1, 0.5-1μg/ml (datasheet PB9544); 9. Primary incubation: Overnight at 4 °C (datasheet PB9544). Watch for: Fixation: Keep fixation consistent across paraffin sections (standard IHC practice; not target-specific); Caveat: Tissue staining has very low agreement with RNA data (HPA tissue IHC); Isoform / epitope: 3 isoforms; epitope coverage needs validation (UniProt); Regulation: Expression regulation is not specified (UniProt). Evidence: UniProt P04798, HPA tissue IHC · Uncertain, HPA ICC-IF · Membrane, Datasheet PB9544, PMC11544920, PMC4201582. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/CYP1A1/immunohistochemistry-ihc-guide.