This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
KRT8 / Keratin, type II cytoskeletal 8 · IHC design guide
Design Immunohistochemistry for KRT8
Plan chromogenic KRT8 IHC on paraffin sections using catalog antibody conditions (datasheet M01421-2). Compare cytoplasmic and membranous epithelial staining with cell-specific positive and negative tissue controls (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
KRT8 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 and membranous tissue staining (HPA tissue IHC) | |
| Staining pattern | Glandular epithelia show cytoplasmic and membranous staining (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet M01421-2) | |
| Positive control | Appendix+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 | Staining and RNA expression show medium consistency (HPA tissue IHC) | |
| Regulation | Intestine/stomach tissue-enhanced RNA (HPA tissue RNA) | |
| Isoform / epitope | 2 isoforms; antibody epitope coverage is unspecified (UniProt; catalog datasheets) |
Section 1
Recommended KRT8 IHC & IF Protocols
The catalog antibody protocol uses EDTA pH 8.0 retrieval (datasheet: M01421-2). One published paraffin-section KRT8 protocol provides an additional starting point (PMC5855799).
| Sample | Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet M01421-2) |
| Fixation | Image fixative and duration unreported (datasheet M01421-2); 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 M01421-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet M01421-2) |
| Primary antibody | Rabbit monoclonal (clone CIG-11) anti-KRT8, 1:50 (datasheet M01421-2) |
| Primary incubation | Overnight at 4 °C (datasheet M01421-2) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet M01421-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | KRT8-positive staining in endocrine cells of appendix (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic and membranous expression in most glandular epithelia, renal tubules and pneumocytes. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet: M01421-2); evaluate the published pressure-cooker retrieval if optimizing staining (PMC5855799).
Section 2
What Is the Expected KRT8 Staining Pattern?
KRT8 is an intracellular intermediate filament protein with no transmembrane segment (UniProt P05787). In paraffin section IHC, expect cytoplasmic and sometimes membranous staining in glandular epithelia, renal tubules and pneumocytes (HPA tissue IHC). HPA rates its tissue staining reliability Enhanced, while reporting medium consistency between antibody staining and RNA expression (HPA tissue IHC).
| Cytoplasmic staining in breast glandular cells or bronchial respiratory epithelial cells. | This fits the reported high staining in those cell types (HPA tissue IHC). A filamentous pattern is biologically plausible because KRT8 contributes to the epithelial intermediate filament network (UniProt P05787). |
| Membranous staining accompanies epithelial cytoplasmic staining. | This can fit the HPA tissue profile, which describes cytoplasmic and membranous expression (HPA tissue IHC). KRT8 has no transmembrane segment, so a membrane-associated appearance does not establish that it spans the membrane (UniProt P05787). |
| Strong nucleus-only staining, with little epithelial cytoplasmic signal. | Treat this as discordant with the usual tissue IHC profile and check controls and detection background (HPA tissue IHC; general IHC practice). UniProt also annotates nucleoplasm and nuclear matrix, so nuclear staining alone cannot prove an artefact (UniProt P05787). |
| Staining predominates in adipocytes or esophageal squamous epithelial cells. | Those cells are reported as not detected (HPA tissue IHC). Review morphology and controls; antibody cross-reactivity or endogenous detection activity are possible general IHC explanations, not established KRT8-specific causes (general IHC practice). |
| Diffuse color covers cells and surrounding tissue, or a known-positive section has no signal. | Neither appearance demonstrates the expected cell-restricted pattern (HPA tissue IHC). Diffuse color warrants background controls; absent signal in a reported high-staining cell type warrants a run and reagent check (general IHC practice). |
💡Expected KRT8 appearanceCall positive when glandular or respiratory epithelial cells show clear cytoplasmic, sometimes membranous staining, with high staining reported in the named example cells (HPA tissue IHC); diffuse tissue-wide color or signal confined to reported negative cell types is suspect (HPA tissue IHC; general IHC practice).
| Cell type and tissue context | HPA reports high staining in breast glandular and bronchial respiratory epithelial cells, but not detected in adipocytes or esophageal squamous epithelial cells (HPA tissue IHC). Score the named cells rather than assuming every cell in a section should stain (general IHC practice). |
| Filament organization and partner | KRT8 is a structural component of simple epithelial intermediate filaments and forms a heterodimer with KRT18 (UniProt P05787). This supports interpreting epithelial cytoplasmic structure in context; it does not make KRT18 staining a substitute for KRT8 detection (UniProt P05787; general IHC practice). |
| Antibody validation and limits | Three listed antibodies have Enhanced IHC validation (HPA antibodies). The tissue profile still reports medium consistency with RNA expression (HPA tissue IHC). These summaries support pattern comparison, but do not establish how a particular catalog antibody performs under your staining conditions (general IHC practice). |
| Isoforms, modifications and processing | UniProt lists two isoforms, modified residues, and a single chain spanning residues 1–483, with no signal peptide or propeptide (UniProt P05787). The supplied record gives no antibody epitope or isoform specificity, so it cannot predict epitope-dependent staining differences (UniProt P05787). |
| IF/ICC Q&A: What should fluorescence show? | HPA reports supported localization to intermediate filaments in ICC-IF (HPA subcellular). That observation can inform compartment interpretation, while this page’s positive tissue calls come from paraffin section IHC (HPA tissue IHC). |
| Situation | Likely cause | Next action |
|---|---|---|
| No color in breast glandular cells or bronchial respiratory epithelial cells. | These are reported high-staining cells (HPA tissue IHC); an empty control may indicate a failed run (general IHC practice). | Check a known-positive section, antibody and detection reagents, and the counterstained section’s morphology (general IHC practice). |
| Color appears throughout the section, including cell-free areas. | Non-specific reagent deposition or incomplete washing can produce diffuse background (general IHC practice). | Review the negative reagent control, washing, blocking and detection steps before scoring cells (general IHC practice). |
| Reported negative cell types stain strongly. | Cross-reactivity or endogenous detection activity may contribute (general IHC practice); HPA reports adipocytes and esophageal squamous cells as not detected (HPA tissue IHC). | Verify cell identity and inspect an appropriate negative control and endogenous activity control (general IHC practice). |
| Signal appears only in nuclei. | This differs from HPA’s usual cytoplasmic and membranous tissue profile, although UniProt includes nuclear locations (HPA tissue IHC; UniProt P05787). | Check epithelial cytoplasm in a known-positive section and compare controls before assigning the nuclear signal to KRT8 (general IHC practice). |
| Signal is weak in an expected positive section. | The run may have limited sensitivity; no KRT8-specific fixation or retrieval effect is established by these sources (general IHC practice; HPA tissue IHC; UniProt P05787). | Check control performance and the validated IHC settings for the antibody in use; optimize retrieval only as a general assay step (general IHC practice). |
| Staining varies among sections or cell populations. | KRT8 distribution depends on the cell type sampled, and HPA reports medium antibody–RNA consistency for its tissue profile (HPA tissue IHC). | Compare matched cell types and section quality, then score localization and intensity within those cells (general IHC practice). |
Experiment evidence
IHC & IF images showing KRT8 staining
M01421-2 · IHCIHC analysis of KRT8 using anti-KRT8 antibody (M01421-2). KRT8 was detected in a paraffin-embedded section of human lung cancer tissue. Heat
M01421-2 · IHCIHC analysis of KRT8 using anti-KRT8 antibody (M01421-2). KRT8 was detected in a paraffin-embedded section of human lung cancer tissue. Heat
M01421-2 · IFImmunofluorescent analysis using the Antibody at 1:150 dilution.
M01421-3 · IHCIHC analysis of Cytokeratin 8 using anti-Cytokeratin 8 antibody (M01421-3). Cytokeratin 8 was detected in paraffin-embedded section of human
M01421-3 · IFIF analysis of Cytokeratin 8 using anti-Cytokeratin 8 antibody (M01421-3). Cytokeratin 8 was detected in immunocytochemical section of U20S
PA1240 · IHCIHC analysis of ITGB3 using anti-ITGB3 antibody (PA1240). ITGB3 was detected in a paraffin-embedded section of human intestinal cancer tissu
M01421-6 · IHCHuman colon carcinoma was stained with anti-Cytokeratin 8 rabbit antibody
M01421-6 · IHCMouse stomach was stained with anti-Cytokeratin 8 rabbit antibody
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000170421-KRT8/tissue/cerebral+cortex#imid_14439408
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000170421-KRT8/tissue/colon#imid_14444502
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000170421-KRT8/tissue/liver#imid_14444511
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000170421-KRT8/tissue/kidney#imid_14444512
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB000131; green = KRT8, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB000131; green = KRT8, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for KRT8 IHC & IF
🧪Run breast first: glandular cells should stain strongly (HPA: High in breast glandular cells). Use adipose tissue as the negative: adipocytes should lack detectable staining (HPA: Not detected in adipocytes); on the breast slide, morphologically identified stromal cells should remain largely unstained relative to glandular cells (UniProt P05787: KRT8 is a simple epithelial intermediate filament protein).
Positive control tissue: Appendix (Endocrine cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show KRT8 in A-431, U-251MG, U2OS, CACO-2, MCF-7, with annotated localisation: Intermediate filaments (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control and a rabbit isotype control matched to the primary antibody’s immunoglobulin class and clonality when known (selected-SKU caption: rabbit anti-KRT8 antibody). Use a KRT8 knockout sample, if available, as a biological specificity control; quench endogenous peroxidase in breast sections before HRP/DAB detection (selected-SKU caption: HRP/DAB detection).
⚠️Feasibility: The selected-SKU paraffin-section example uses heat retrieval in EDTA at pH 8.0, so assess retrieval with the chosen specimen preparation (selected-SKU caption: EDTA heat retrieval). A target-specific fixation window or fixation effect is unreported, and the exact selected-SKU caption does not state a fixative (selected-SKU caption: fixative unreported). The supplied evidence does not establish that frozen sections or IF are easier; for chromogenic breast IHC, distinguish glandular staining from background in adjacent stroma (HPA: High in breast glandular cells; UniProt P05787: simple epithelial intermediate filaments).
HPA tissue IHC evidence for KRT8
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 |
|---|---|---|---|---|
| Appendix | Endocrine cells | High | Protein (IHC) | HPA → |
| Breast | Glandular cells | High | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | High | Protein (IHC) | HPA → |
| Cervix | Glandular cells | High | Protein (IHC) | HPA → |
| Colon | Endocrine cells | High | 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 → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
| Cerebellum | Cells in granular layer | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced KRT8 IHC Tips
Troubleshoot KRT8 chromogenic IHC in paraffin sections using the catalog antibody’s tissue image and known intermediate filament localisation.
What retrieval should I try when KRT8 staining is weak in paraffin sections?
Start with heat-mediated EDTA at pH 8.0 for KRT8 IHC in paraffin sections (datasheet M01421-2). The catalog antibody stained a paraffin-embedded human lung cancer section after this retrieval and 1:50 primary incubation overnight at 4°C (datasheet M01421-2). If the control remains weak, adjust heating and cooling consistently across matched sections before trying another buffer as a fallback (standard IHC practice). Assess whether cytoplasmic filament staining improves without loss of tissue morphology; KRT8 is an intermediate filament protein (UniProt P05787; HPA subcellular). Keep a no-primary control alongside each retrieval condition to check nonspecific detection (standard IHC practice).
How should I troubleshoot variable KRT8 staining between paraffin blocks?
Record each block’s fixative, fixation duration, processing history and section age before comparing staining (standard IHC practice). The selected image establishes paraffin embedding but does not report its fixative, so target-specific fixation sensitivity for this antibody is unknown (datasheet M01421-2). Run matched sections from each block in the same batch with EDTA at pH 8.0 and the same primary incubation (datasheet M01421-2; standard IHC practice). Compare staining in preserved epithelial structures and review morphology before changing retrieval or antibody concentration (HPA tissue IHC; standard IHC practice). Do not assign block-to-block differences to a KRT8-specific fixation effect without controlled evidence (standard IHC practice).
Where should convincing KRT8 signal appear in a tissue section?
Expect predominantly cytoplasmic staining associated with the intermediate filament network in epithelial cells (UniProt P05787; HPA subcellular). Tissue IHC also reports cytoplasmic and membranous expression in most glandular epithelia, renal tubules and pneumocytes (HPA tissue IHC). Check whether the signal follows intact cell boundaries and cytoplasm rather than forming a uniform deposit over nuclei, lumens or damaged edges (standard IHC practice). UniProt additionally lists nucleoplasm and nuclear matrix locations, so isolated nuclear DAB staining needs corroboration before interpretation (UniProt P05787; standard IHC practice). Compare the suspected pattern with section morphology, a known positive area and a no-primary control on the same run (standard IHC practice).
Can this staining distinguish KRT8 isoforms or a modified epitope?
Do not score the two KRT8 isoforms separately unless the antibody’s mapped epitope and isoform reactivity are documented (UniProt P05787; standard IHC practice). KRT8 has 2 listed isoforms and an intermediate filament rod spanning residues 91–402, but the supplied tissue image does not map this antibody’s epitope (UniProt P05787; datasheet M01421-2). The record lists numerous modified residues, including phosphoserines near the amino terminus, without establishing their effect on this antibody’s tissue staining (UniProt P05787). If staining changes after retrieval, compare matched sections and controls before attributing the difference to isoform abundance or modification (standard IHC practice). Report the result as KRT8 immunoreactivity unless specificity evidence supports a narrower claim (standard IHC practice).
How can IF help evaluate an ambiguous KRT8 IHC pattern?
For a separate IF assessment, multiplex KRT8 with KRT18 to identify cells bearing its expected type I keratin partner (UniProt P05787). Choose spectrally separated fluorophores and place the weaker signal in a red or far-red channel if tissue autofluorescence obscures shorter wavelengths (standard IF practice). KRT8 has no transmembrane segment and is primarily associated with cytoplasmic intermediate filaments, so permeabilisation should provide access to its intracellular epitope (UniProt P05787; HPA subcellular). Titrate permeabilisation against filament preservation, since the antibody epitope and IF-specific conditions are not supplied here (standard IF practice). Include single-stain, no-primary and autofluorescence controls before comparing IF localisation with DAB staining (standard IF practice).
What should I change when DAB background obscures KRT8-positive cells?
First inspect no-primary and secondary-only controls to separate detection background from primary-antibody staining (standard IHC practice). The selected tissue image used 10% goat serum blocking, 1:50 primary overnight at 4°C, and peroxidase-conjugated secondary for 30 minutes at 37°C (datasheet M01421-2). If diffuse staining persists, titrate the primary, review wash stringency and apply an appropriate endogenous peroxidase block before DAB development (standard chromogenic IHC practice). Assess whether background lies in tissue folds, damaged edges or extracellular material rather than epithelial cytoplasm (standard IHC practice; HPA tissue IHC). Keep development conditions identical across comparison sections so differences remain interpretable (standard IHC practice).
How should I quantify KRT8 staining across tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the tissue compartment and eligible intact cells before scoring, because KRT8 staining varies by cell type (HPA tissue IHC; standard IHC practice). Report the percentage of positive epithelial cells and an H-score calculated as 1 × % weak + 2 × % moderate + 3 × % strong where ordinal intensity scoring is appropriate (standard IHC practice). For spatial counts, report positive cells per mm² of viable, annotated tissue (standard IHC practice). Normalise comparisons to the same cell population, sampled area, staining batch and image settings, excluding necrosis and folds (standard IHC practice). State the positivity threshold and whether membranous-adjacent cytoplasmic staining was counted (HPA tissue IHC; standard IHC practice).
How can I distinguish true KRT8 staining from artefact?
Give greatest weight to staining in intact epithelial cytoplasm with a plausible filamentous or cytoplasmic pattern (UniProt P05787; HPA subcellular; standard IHC practice). The tissue atlas reports high staining in breast glandular cells and bronchial respiratory epithelial cells, while adipocytes and esophageal squamous epithelial cells are listed as not detected (HPA tissue IHC). Unexpected staining in those negative cell populations needs independent confirmation rather than automatic biological interpretation (HPA tissue IHC; standard IHC practice). Treat edge-restricted deposits, necrotic regions and no-primary DAB signal as possible artefacts, including endogenous enzyme activity (standard IHC practice). Review morphology and repeat with an appropriate peroxidase block and matched controls before calling an unusual compartment positive (standard IHC practice).
Boster reagents
Best KRT8 / Keratin, type II cytoskeletal 8 IHC Antibodies
Anti-KRT8 entries include human paraffin-section IHC and human tissue IF images; catalog reactivity spans human, mouse and rat (M01421-2/3 IHC captions; M01421-3 IF caption and catalog).
Real IHC data
Anti-Cytokeratin 8 KRT8 Rabbit Monoclonal Antibody
Cat # M01421-2
Real IHC data
Anti-Cytokeratin 8 KRT8 Antibody ® (monoclonal, 3G9)
Cat # M01421-3
Real IHC data
Anti-Cytokeratin 8/KRT8 Antibody ®
Cat # PA1240
Real IHC data
Anti-Cytokeratin 8 Rabbit Monoclonal Antibody
Cat # M01421-6
M01421-2 shows human lung cancer paraffin-section IHC, and M01421-3 shows human rectal cancer paraffin-section IHC (respective image captions). M01421-6 shows human colon carcinoma staining, while PA1240’s IHC caption identifies its target as ITGB3, so that image does not establish KRT8 staining (respective image captions).
Which to pick: For tissue IHC, M01421-2 has a rabbit monoclonal antibody and an IHC caption documenting paraffin sections, EDTA pH 8 retrieval and 1:50 dilution; the fixative is unreported (M01421-2 catalog and IHC caption). For IF/ICC, M01421-3 lists both applications and has tissue IF images; its own IHC caption documents paraffin sections and EDTA pH 8 retrieval, with fixative unreported (M01421-3 catalog, IF captions and IHC caption). For human, mouse and rat coverage, M01421-6 lists IHC and IF for a rabbit monoclonal antibody, but its human colon carcinoma IHC caption does not report section processing or fixative (M01421-6 catalog and IHC caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P05787 (K2C8_HUMAN, Keratin, type II cytoskeletal 8).
- Human Protein Atlas. KRT8 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. KRT8 subcellular location (ICC-IF): Localized to the intermediate filaments..
- Human Protein Atlas. KRT8 antibody validation summary (3 antibodies).
- Cytokeratin-8 in Anaplastic Thyroid Carcinoma: More Than a Simple Structural Cytoskeletal Protein. International journal of molecular sciences 2018 — PMC5855799.
- Merkel Cell Polyomavirus T Antigens Induce Merkel Cell-Like Differentiation in GLI1-Expressing Epithelial Cells. Cancers 2020 — PMC7409360.
- An Airway Protection Program Revealed by Sweeping Genetic Control of Vagal Afferents. Cell 2020 — PMC7197391.
- High KRT8 Expression Independently Predicts Poor Prognosis for Lung Adenocarcinoma Patients. Genes 2019 — PMC6360019.
- PubMed PMID:1691124 — UniProt-cited evidence.
- PubMed PMID:1692965 — UniProt-cited evidence.
- PubMed PMID:1705144 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for KRT8 (Keratin, type II cytoskeletal 8). Expected localisation Cytoplasmic and membranous tissue staining (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet M01421-2). Validated IHC antibody: M01421-2 at 1:50 (the product's own IHC validation image is shown). Controls (HPA): positive Appendix (Endocrine cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet M01421-2); 2. Fixation: Image fixative and duration unreported (datasheet M01421-2); 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 M01421-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet M01421-2); 8. Primary antibody: Rabbit monoclonal (clone CIG-11) anti-KRT8, 1:50 (datasheet M01421-2); 9. Primary incubation: Overnight at 4 °C (datasheet M01421-2). Watch for: Fixation: Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific); Caveat: Staining and RNA expression show medium consistency (HPA tissue IHC); Isoform / epitope: 2 isoforms; antibody epitope coverage is unspecified (UniProt; catalog datasheets); Regulation: Intestine/stomach tissue-enhanced RNA (HPA tissue RNA). Evidence: UniProt P05787, HPA tissue IHC · Enhanced, HPA ICC-IF · intermediate filaments., Datasheet M01421-2, PMC5855799. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/KRT8/immunohistochemistry-ihc-guide.