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PTK7 / Inactive tyrosine-protein kinase 7 · IHC design guide
Design Immunohistochemistry for PTK7
Plan PTK7 chromogenic IHC in paraffin sections using cytoplasmic tissue staining as the reference pattern (HPA tissue IHC). Endometrial stromal cells show high staining, while adipocytes are not detected (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
PTK7 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 signal (HPA tissue IHC); membrane and junctional location (UniProt) | |
| Staining pattern | Cytoplasmic staining in several tissues, high in endometrial stroma (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Endometrium+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 | A secreted variant may complicate tissue RNA–protein agreement (HPA tissue IHC) | |
| Regulation | Expression varies by tissue (HPA tissue IHC) | |
| Isoform / epitope | 6 isoforms; map the epitope to the extracellular or cytoplasmic region (UniProt) |
Section 1
Recommended PTK7 IHC & IF Protocols
The catalog antibody IHC-P protocol is followed by 3 published PTK7 IHC workflows for breast, lung, and pancreatic tissue (PMC11430626; PMC4084668; PMC10323888).
| Sample | Paraffin-embedded tissue sections; fixative not specified (datasheet A02957; sample unspecified) |
| Fixation | Image fixative and duration unreported (datasheet A02957); 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 | Mouse monoclonal (clone 4F9) anti-PTK7, 1:200-1:1000 (datasheet A02957) |
| 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 | PTK7-positive staining in cells in endometrial stroma of endometrium (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in several tissues. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 HIER at 95–98 °C for 20 min (page retrieval rule); use pepsin or CC1 when following the corresponding published workflow (PMC4084668; PMC10323888).
Section 2
What Is the Expected PTK7 Staining Pattern?
PTK7 is a transmembrane protein with an extracellular region and cytoplasmic tail (UniProt Q13308 topology). Expect staining at cell borders, with possible cytoplasmic staining: HPA reports cytoplasmic expression across several tissues and rates its tissue IHC profile Approved despite low agreement with RNA data (HPA tissue IHC). The strongest listed signal is in endometrial stromal cells; several epithelial and neuronal cell types show medium staining (HPA tissue IHC).
| Cell-border staining in endometrial stromal cells, with possible cytoplasmic signal. | This fits PTK7 membrane localization (UniProt Q13308 subcellular location) and HPA's High endometrial stromal IHC signal and broader cytoplasmic profile (HPA tissue IHC). Assess the stained cells and compartment together; border staining alone does not establish antibody specificity. |
| A strong nuclear-only pattern, without convincing cell-border or cytoplasmic staining. | Nuclear-only staining does not match the reported cell membrane and cell-junction localization (UniProt Q13308 subcellular location) or HPA's cytoplasmic tissue profile (HPA tissue IHC). Treat it as a possible artefact and check controls and detection conditions before scoring it as PTK7. |
| Strong staining in adipocytes or cardiomyocytes. | HPA lists PTK7 as Not detected in adipocytes and cardiomyocytes (HPA tissue IHC). Check whether the signal tracks those cells or tissue edges and whether a no-primary control also stains. Cross-reactivity or endogenous detection activity is plausible, but the slide alone cannot distinguish them. |
| Diffuse color across cells, stroma, and blank areas, obscuring cell borders. | That distribution is difficult to reconcile with a cell-associated PTK7 call (UniProt Q13308 subcellular location; HPA tissue IHC). In chromogenic IHC, background can arise from detection reagents or insufficient blocking or washing (general IHC practice). Compare a no-primary control and judge signal only where cell identity remains clear. |
| No convincing staining in an endometrial stromal positive-control section. | HPA reports High staining in endometrial stromal cells (HPA tissue IHC), so absence warrants a technical check. Confirm that the expected cells are present, then review antibody dilution, retrieval and detection controls (general IHC practice). An HPA tissue pattern does not guarantee every specimen will stain. |
💡Expected PTK7 appearanceA convincing positive is cell-associated staining in the expected cells, potentially outlining membranes and showing cytoplasmic signal; endometrial stromal cells are listed as High (UniProt Q13308 subcellular location; HPA tissue IHC). Strong nuclear-only or acellular diffuse color is suspect (general IHC interpretation).
| Membrane topology and observed tissue compartment | PTK7 has an extracellular region at residues 31–704, a transmembrane segment at 705–725, and a cytoplasmic region at 726–1070 (UniProt Q13308 topology). HPA describes tissue IHC staining as cytoplasmic (HPA tissue IHC). Score visible compartment and cell type; do not require a perfect membrane outline in every positive cell. |
| Cell and tissue selection | HPA lists endometrial stromal cells as High; breast glandular, bronchial respiratory epithelial, and kidney tubular cells as Medium (HPA tissue IHC). Use a listed cell population to assess a positive control. HPA reports adipocytes and cardiomyocytes as Not detected, useful context for interpreting unexpected staining (HPA tissue IHC). |
| Variant and validation limits | UniProt lists 6 PTK7 isoforms (UniProt Q13308 isoforms). HPA notes that at least one protein variant is secreted and that RNA and protein locations may differ (HPA tissue IHC reliability description). HPA rates the tissue profile Approved with low RNA–staining consistency and lists HPA003222 IHC as Approved (HPA tissue IHC; HPA antibodies). Interpret discordance cautiously. |
| IF/ICC Q: What localization is expected? | A: HPA reports mainly plasma membrane and cytosol, with additional vesicles; its plasma-membrane assignment is Supported, cytosol Uncertain, and vesicles Approved (HPA subcellular ICC-IF). UniProt also places PTK7 at cell junctions and the leading edge of migrating cells (UniProt Q13308 subcellular location). These IF observations are context, not an IHC staining requirement. |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected endometrial stromal signal is absent. | The expected cells may be missing, or the IHC workflow may have failed; HPA lists these cells as High (HPA tissue IHC). | Verify stromal cells on the section. Check the IHC-validated antibody's specified dilution and retrieval procedure, then confirm detection with an appropriate positive control (general IHC practice). |
| Only nuclei appear positive. | This conflicts with PTK7 cell membrane and junction localization and HPA's cytoplasmic tissue profile (UniProt Q13308 subcellular location; HPA tissue IHC). | Review the no-primary control and staining distribution. Reassess antigen retrieval and detection conditions using the antibody's IHC procedure before assigning a PTK7 score (general IHC practice). |
| Adipocytes or cardiomyocytes stain strongly. | HPA lists these cells as Not detected; unexpected signal may reflect cross-reactivity or endogenous detection activity (HPA tissue IHC; general IHC practice). | Compare a no-primary control and inspect the cell identity. If background persists, review blocking and the detection system; if only the primary-stained slide is positive, reconsider antibody specificity (general IHC practice). |
| Diffuse chromogen obscures cell boundaries. | Nonspecific background can obscure a cell-associated pattern (general IHC practice); PTK7 is reported at the membrane and junctions, while HPA also observes cytoplasmic tissue staining (UniProt Q13308 subcellular location; HPA tissue IHC). | Inspect no-primary and positive-control sections. Review blocking, washing, primary dilution and detection development according to the IHC workflow (general IHC practice). |
| Cytoplasmic staining is present, but membrane outlines are faint. | HPA's tissue IHC profile is cytoplasmic, while UniProt assigns PTK7 to the membrane (HPA tissue IHC; UniProt Q13308 subcellular location). | Record the observed compartment and cell type. Compare a listed positive tissue and controls before judging the result; do not reject cytoplasmic staining solely because borders are faint (HPA tissue IHC; general IHC interpretation). |
| Protein staining disagrees with RNA abundance. | HPA reports low staining–RNA consistency and says a secreted protein variant can complicate agreement between RNA and protein location (HPA tissue IHC reliability description). | Score the observed IHC pattern and document the mismatch. Check antibody controls and tissue cell composition; avoid treating RNA abundance alone as proof of a positive or negative IHC result (HPA tissue IHC; general IHC interpretation). |
Experiment evidence
IHC & IF images showing PTK7 staining
A02957 · IHCImmunohistochemistry analysis of paraffin-embedded lung cancer tissues with DAB staining using CCK-4 Monoclonal Antibody.
A02957-1 · IHCImmunohistochemistry of PTK7 in human colon tissue with PTK7 antibody at 2.5 μg/mL.
A02957-1 · IFImmunofluorescence of PTK7 in Human Colon cells with PTK7 antibody at 20 μg/mL.
A02957-2 · IHCFormalin-fixed and paraffin-embedded human cancer tissue reacted with the primary antibody, which was peroxidase-conjugated to the secondary
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000112655-PTK7/tissue/cerebral+cortex#imid_1189856
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000112655-PTK7/tissue/colon#imid_1189774
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000112655-PTK7/tissue/liver#imid_1189775
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000112655-PTK7/tissue/kidney#imid_1189792
HPA · ICC-IF Rh30Human Protein Atlas immunofluorescence, Rh30, antibody HPA003222; green = PTK7, blue = nucleus, red = microtubules.
HPA · ICC-IF Rh30Human Protein Atlas immunofluorescence, Rh30, antibody HPA003222; green = PTK7, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for PTK7 IHC & IF
🧪Run endometrium first: cells in the endometrial stroma should stain (HPA: High). Run adipose tissue as a negative comparator because adipocytes are not detected (HPA: Not detected); on the endometrial slide, assess background in neighboring cells without visible staining, without assuming they are PTK7-negative.
Positive control tissue: Endometrium (Cells in endometrial stroma, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show PTK7 in Rh30, SH-SY5Y, U2OS, with annotated localisation: Plasma membrane (supported), Cytosol (uncertain) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control and an isotype control matched to the primary antibody’s host species and clonality; PTK7-knockout tissue, if available, provides a biological negative. For chromogenic staining of endometrium, quench endogenous peroxidase and check blood-rich areas for residual DAB background (standard IHC practice).
⚠️Feasibility: A target-specific fixation window and retrieval dependency are unreported in the supplied evidence; the selected A02957 paraffin-section caption also leaves the fixative unreported (A02957 caption). No supplied comparison establishes whether frozen-section IHC or IF is easier than paraffin IHC. In endometrial sections, blood-associated endogenous peroxidase can complicate DAB interpretation (standard IHC practice).
HPA tissue IHC evidence for PTK7
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Low consistency between antibody staining and RNA expression data. At least one protein variant secreted, tissue location of RNA and protein might differ and correlation is complex.). 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 |
|---|---|---|---|---|
| Endometrium | Cells in endometrial stroma | High | Protein (IHC) | HPA → |
| Breast | Glandular cells | Medium | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Medium | Protein (IHC) | HPA → |
| Caudate | Neuronal cells | Medium | Protein (IHC) | HPA → |
| Cerebellum | Purkinje 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 → |
| Heart muscle | Cardiomyocytes | Not detected | Protein (IHC) | HPA → |
| Parathyroid gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced PTK7 IHC Tips
These questions address PTK7 staining in paraffin sections with chromogenic detection; the IF question covers a separate assay.
What retrieval should I start with for PTK7 in paraffin sections?
Start with citrate buffer at pH 6.0, heated to 95–98 °C for 20 min (page retrieval setting). Keep section thickness, heating, cooling, and antibody conditions matched across the first comparison so retrieval is the variable under test (standard IHC practice). If staining is weak, compare a second section using EDTA at pH 9.0 as a fallback, while checking that tissue structure remains intact (standard IHC practice). Score signal separately at cell borders and in cytoplasm: PTK7 is a membrane protein, while tissue IHC also reports cytoplasmic staining (UniProt Q13308 topology; HPA tissue IHC profile).
How should I evaluate whether fixation is affecting PTK7 staining?
Target-specific fixation sensitivity is unknown: the A02957 image shows DAB staining in paraffin-embedded lung cancer tissue, but its caption does not state the fixative (A02957 tissue-IHC caption). Record the actual fixative, time before fixation, fixation duration, and tissue thickness for every specimen before comparing staining (standard IHC practice). If fixation varies, stain matched sections together with the same citrate pH 6.0, 20 min retrieval and detection run (page retrieval setting; standard IHC practice). Compare staining with preserved morphology and a reference section processed in the same run; do not assign a PTK7-specific fixation effect from tissue patterns alone (standard IHC practice).
Where should PTK7 staining appear, and how should I assess cytoplasmic signal?
Assess membranous staining at cell borders first: PTK7 has an extracellular region at residues 31–704 and a transmembrane segment at 705–725 (UniProt Q13308 topology). Junctional or leading-edge enrichment can also fit its reported distribution, provided the relevant structures are identifiable in the section (UniProt Q13308 subcellular annotation). Do not automatically reject cytoplasmic DAB staining, because tissue IHC reports cytoplasmic expression and cell imaging reports a supported plasma-membrane location with uncertain cytosol and approved vesicles (HPA tissue IHC profile; HPA subcellular). Score border and cytoplasmic staining separately, then compare each pattern with cell morphology and controls on the same slide (standard IHC practice).
How can epitope position change the PTK7 staining I interpret?
First confirm the antibody's documented immunogen or epitope before assigning a stained compartment to a PTK7 molecular form (standard IHC practice). PTK7 has 6 listed isoforms, an extracellular region at residues 31–704, and a cytoplasmic region at 726–1070 (UniProt Q13308 isoforms and topology). Those coordinates indicate which side of the membrane a mapped epitope occupies, but they do not establish which isoforms the catalog antibody detects (UniProt Q13308 topology; standard IHC practice). Because HPA notes that at least one protein variant is secreted, evaluate extracellular-looking deposits separately and avoid identifying a specific variant from DAB localisation alone (HPA tissue IHC reliability description).
How should I check PTK7 localisation in a separate IF experiment?
For the separate IF assay, multiplex PTK7 with a marker for the cell type being assessed and compare signal within those marked cells (standard IF practice). Choose fluorophores after inspecting unstained tissue for autofluorescence, using a spectrally distinct channel where background is lower and including single-label controls (standard IF practice). If the antibody epitope is extracellular, test staining without permeabilisation; if it is cytoplasmic, test a permeabilised condition, since PTK7 spans residues 705–725 (UniProt Q13308 topology; standard IF practice). Examine borders, cytosol, and puncta separately: HPA supports plasma-membrane localisation, labels cytosol uncertain, and approves vesicular localisation (HPA subcellular).
How can I distinguish PTK7 signal from chromogenic background?
Include a no-primary control and assess diffuse DAB colour, precipitate, and staining outside intact cells before calling a section positive (standard IHC practice). Use an endogenous peroxidase block before enzyme-based detection, and check whether changing blocking or wash conditions reduces nonspecific signal (standard chromogenic IHC practice). PTK7 is reported at the cell membrane and junctions, while tissue IHC also describes cytoplasmic staining, so neither compartment alone establishes specificity (UniProt Q13308 subcellular annotation; HPA tissue IHC profile). Compare candidate-positive cells with the no-primary section and a concurrently stained reference tissue; record edge staining and damaged areas separately (standard IHC practice).
How should I quantify heterogeneous PTK7 DAB staining? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and analysis area before scoring, then report the percentage of positive cells and an H-score from 0–300 where intensity is reproducibly graded (standard IHC scoring practice). Score membranous and cytoplasmic compartments separately because PTK7 is a membrane protein and tissue IHC also reports cytoplasmic expression (UniProt Q13308 topology; HPA tissue IHC profile). Normalize counts to the number of eligible cells, or report positive-cell density per mm² of viable assessed tissue when cell counting is impractical (standard IHC practice). Keep thresholds, imaging settings, and exclusion criteria fixed across sections, and report the no-primary background alongside the measured signal (standard IHC practice).
What evidence makes a PTK7-positive IHC result convincing?
A convincing result identifies stained, intact cells and records whether DAB is membranous, junctional, or cytoplasmic, rather than relying on overall section colour (UniProt Q13308 subcellular annotation; HPA tissue IHC profile; standard IHC practice). Compare the cell type with reference observations: HPA reports high staining in endometrial stromal cells and no detection in adipocytes, but rates its tissue IHC Approved with low RNA–protein consistency (HPA tissue IHC). Treat staining limited to cut edges, necrotic regions, or no-primary controls as suspect, and check endogenous enzyme background (standard chromogenic IHC practice). Confirm unexpected compartments or cell populations with independent antibody or orthogonal evidence before interpreting biological differences (standard IHC practice).
Boster reagents
Best PTK7 / Inactive tyrosine-protein kinase 7 IHC Antibodies
The catalog shows PTK7 IHC images from human lung cancer, colon tissue, and cancer tissue, plus an IF image from human colon cells (catalog image captions).
Real IHC data
Anti-CCK-4 PTK7 Monoclonal Antibody
Cat # A02957
Real IHC data
Anti-PTK7 Antibody
Cat # A02957-1
Real IHC data
Anti-CCK4 (PTK7) Antibody (N-term)
Cat # A02957-2
A02957 shows IHC in human lung cancer paraffin sections; IF is listed for human samples, but no IF image is supplied (catalog image caption; catalog applications/reactivity). A02957-1 shows IHC in human colon tissue and IF in human colon cells; A02957-2 shows IHC in formalin-fixed, paraffin-embedded human breast carcinoma and hepatocarcinoma (catalog image captions).
Which to pick: For tissue IHC, choose A02957-2 when documented paraffin-section paraffin-embedded examples matter (catalog image caption); A02957 shows paraffin-section IHC, but its caption does not report the fixative (catalog image caption). For IF/ICC, choose A02957-1 because its catalog includes IF and shows staining in human colon cells (catalog applications and IF image caption). A02957-1 is also the cross-species candidate because its stated reactivity includes human, mouse, and rat, though its supplied IHC image shows human colon tissue only and does not report the fixative (catalog reactivity and IHC image caption). The selected A02957 tissue-IHC caption documents paraffin sections, but does not specify the fixative (selected-SKU IHC image A02957).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q13308 (PTK7_HUMAN, Inactive tyrosine-protein kinase 7).
- Human Protein Atlas. PTK7 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. PTK7 subcellular location (ICC-IF): Mainly localized to the plasma membrane and cytosol. In addition localized to vesicles..
- Human Protein Atlas. PTK7 antibody validation summary (1 antibodies).
- Protein Tyrosine Kinase 7 (PTK7) in Breast Cancer: A Retrospective Analysis of Tumour Expression and Association with Clinical Outcome. Cancers 2024 — PMC11430626.
- A meta-analysis of lung cancer gene expression identifies PTK7 as a survival gene in lung adenocarcinoma. Cancer research 2014 — PMC4084668.
- SALL4-related gene signature defines a specific stromal subset of pancreatic ductal adenocarcinoma with poor prognostic features. Molecular oncology 2023 — PMC10323888.
- PTK7, a Catalytically Inactive Receptor Tyrosine Kinase, Increases Oncogenic Phenotypes in Xenograft Tumors of Esophageal Squamous Cell Carcinoma KYSE-30 Cells. International journal of molecular sciences 2022 — PMC8876147.
- PubMed PMID:7478540 — UniProt-cited evidence.
- PubMed PMID:8882711 — UniProt-cited evidence.
- PubMed PMID:12427550 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for PTK7 (Inactive tyrosine-protein kinase 7). Expected localisation Cytoplasmic tissue signal (HPA tissue IHC); membrane and junctional location (UniProt). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A02957 at 1:200-1:1000 (the product's own IHC validation image is shown). Controls (HPA): positive Endometrium (Cells in endometrial stroma); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded tissue sections; fixative not specified (datasheet A02957; sample unspecified); 2. Fixation: Image fixative and duration unreported (datasheet A02957); 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: Mouse monoclonal (clone 4F9) anti-PTK7, 1:200-1:1000 (datasheet A02957); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections. (standard IHC practice; not target-specific); Caveat: A secreted variant may complicate tissue RNA–protein agreement (HPA tissue IHC); Isoform / epitope: 6 isoforms; map the epitope to the extracellular or cytoplasmic region (UniProt); Regulation: Expression varies by tissue (HPA tissue IHC). Evidence: UniProt Q13308, HPA tissue IHC · Approved, HPA ICC-IF · Mainly localized to the plasma membrane and cytosol. In addition…, Datasheet A02957, PMC11430626, PMC4084668. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/PTK7/immunohistochemistry-ihc-guide.