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PTN / Pleiotrophin · IHC design guide
Design Immunohistochemistry for PTN
Plan paraffin-section PTN IHC around cytoplasmic staining in cortical neurons, parathyroid glandular cells and pachytene spermatocytes (HPA tissue IHC). This guide covers fixation, antibody use, detection and scoring while accounting for PTN secretion and cell-surface binding (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
PTN 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 | Observed cytoplasmic staining (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic neurons, spermatocytes and endocrine cells (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A01368-2) | |
| Positive control | Cerebral cortex+3 more · see all | |
| Negative control | Adrenal gland+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 | Secreted PTN binds cell-surface proteoglycans (UniProt) | |
| Regulation | Expression induction is unspecified (UniProt) | |
| Isoform / epitope | No isoforms annotated; mature chain spans residues 33–168 (UniProt) |
Section 1
Recommended PTN IHC & IF Protocols
Compare the catalog antibody’s IHC-P protocol (datasheet A01368-2) with published PTN protocols for thyroid, pancreatic, and sheep tooth-socket sections (PMC4767803; PMC5467077; PMC10099163).
| Sample | Paraffin-embedded human glioma tissue; fixative not specified (datasheet A01368-2) |
| Fixation | Image fixative and duration unreported (datasheet A01368-2); 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 A01368-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A01368-2) |
| Primary antibody | Rabbit anti-PTN, 2-5 μg/ml (datasheet A01368-2) |
| Primary incubation | Overnight at 4 °C (datasheet A01368-2) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A01368-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | PTN-positive staining in neuronal cells of cerebral cortex (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in spermatocytes, neurons in cerebral cortex, and endocrine cells in parathyroid and pituitary gland. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 for the catalog antibody (datasheet A01368-2); compare published citrate retrieval on matched sections if staining needs optimization (PMC4767803; PMC10099163).
Section 2
What Is the Expected PTN Staining Pattern?
PTN is a secreted protein with no transmembrane segment (UniProt P21246 topology). In paraffin-section IHC, HPA reports cytoplasmic staining in cerebral cortex neurons, parathyroid glandular cells, pachytene spermatocytes, and anterior pituitary cells (HPA tissue IHC). HPA rates its tissue pattern Enhanced, while noting that a secreted protein’s RNA-producing cells and protein location may differ (HPA tissue IHC).
| Distinct cytoplasmic staining in cerebral cortex neurons, parathyroid glandular cells, or pachytene spermatocytes. | These are HPA High IHC examples and suitable reference patterns (HPA tissue IHC). Compare staining with the expected cell population and a matched negative control; intensity alone does not establish specificity (general IHC practice). |
| Predominantly nuclear staining, with little cytoplasmic signal in an HPA-positive cell population. | A nuclear-dominant pattern does not match HPA’s reported cytoplasmic tissue staining or its supported endoplasmic-reticulum ICC-IF location (HPA tissue IHC; HPA subcellular). Check nuclear counterstain, detection controls, and antibody specificity before calling it PTN (general IHC practice). |
| Strong staining in an HPA-listed undetected cell population, such as adrenal glandular cells or caudate glial cells. | That result differs from the specified HPA cell-level observations, though it does not prove universal absence of PTN in those tissues (HPA tissue IHC). Assess cross-reactivity and endogenous detection activity with appropriate controls (general IHC practice). |
| Diffuse chromogen across many cell types, including negative-control areas. | A widespread pattern obscures the cell-specific cytoplasmic observations reported by HPA (HPA tissue IHC). Review primary-omission and detection controls, blocking, washing, and development time to identify background (general IHC practice). |
| No staining in cerebral cortex neurons, parathyroid glandular cells, and pachytene spermatocytes. | These populations are reported High, so a blank run calls for an assay check before interpreting other sections as negative (HPA tissue IHC). Verify tissue identity, antibody IHC validation, reagent activity, retrieval conditions, and controls (general IHC practice). |
💡Expected PTN appearanceCall an IHC result positive when cytoplasmic staining is clear in HPA High cerebral cortex neurons, parathyroid glandular cells, or pachytene spermatocytes; isolated nuclear staining or uniform chromogen in HPA-undetected populations warrants control review (HPA tissue IHC; general IHC practice).
| Cell and tissue selection | HPA reports High staining in cortex neurons, parathyroid glandular cells, and pachytene spermatocytes; anterior pituitary cells are Medium (HPA tissue IHC). Select a named positive cell population for run assessment rather than treating every cell in that tissue as positive (general IHC practice). |
| Secretion and compartment | PTN has a signal peptide and is secreted, with no transmembrane segment (UniProt P21246). HPA describes cytoplasmic tissue staining and warns that RNA and protein locations may differ for secreted proteins (HPA tissue IHC). Extracellular signal therefore needs tissue and control context before assignment. |
| Processing and unknown epitope | UniProt annotates signal peptide residues 1–32 and mature PTN residues 33–168, with no propeptide or annotated isoform (UniProt P21246). The supplied sources give no antibody epitope, so they cannot establish which processed form an IHC stain detects or predict a retrieval condition. |
| Antibody evidence | CAB017685 has Enhanced IHC validation; HPA073913 has Approved ICC validation with no IHC status supplied (HPA antibodies). Use an IHC-validated antibody for the paraffin-section comparison and interpret each antibody within its listed application (HPA antibodies; general IHC practice). |
| IF/ICC comparison — Q: What location is reported? | A: HPA reports supported endoplasmic-reticulum localization from ICC-IF and lists AF22 images (HPA subcellular). This is an IF/ICC comparison point, while the paraffin IHC expectation comes from HPA’s cytoplasmic tissue observations (HPA tissue IHC). |
| Situation | Likely cause | Next action |
|---|---|---|
| The known-positive section is blank. | The result conflicts with HPA High staining in the specified cortex, parathyroid, or testis cell populations (HPA tissue IHC); the failed assay step is undetermined. | Confirm the named cells are present, check the IHC antibody and detection controls, then optimize retrieval and dilution as general paraffin-IHC variables (HPA antibodies; general IHC practice). |
| Only nuclei are strongly colored. | A nuclear-dominant pattern differs from HPA’s cytoplasmic tissue profile and supported endoplasmic-reticulum ICC-IF location (HPA tissue IHC; HPA subcellular). | Check the counterstain and primary-omission control; compare with an HPA High cell population before assigning the signal to PTN (HPA tissue IHC; general IHC practice). |
| Negative-control areas show broad brown staining. | The pattern may reflect endogenous enzyme activity, nonspecific detection, or excess chromogen development (general chromogenic IHC practice). | Run primary-omission and relevant enzyme-block controls, inspect washing and blocking, and adjust development time (general chromogenic IHC practice). |
| HPA-undetected glandular cells stain as strongly as the positive reference. | For example, adrenal glandular cells are Not detected, whereas parathyroid glandular cells are High in HPA’s specified observations (HPA tissue IHC). | Compare the cell populations side by side, inspect negative controls, and assess cross-reactivity before scoring that staining as PTN (HPA tissue IHC; general IHC practice). |
| Signal looks extracellular rather than cytoplasmic. | PTN is secreted, and HPA cautions that RNA and protein locations can differ; its reported tissue IHC profile is cytoplasmic in specified cells (UniProt P21246; HPA tissue IHC). | Record the extracellular distribution separately, verify cell-associated signal in an HPA High reference, and assess background controls before interpreting deposits (HPA tissue IHC; general IHC practice). |
| An ICC-positive antibody gives an uncertain paraffin-IHC pattern. | HPA073913 is Approved for ICC but has no IHC status supplied; CAB017685 has Enhanced IHC validation (HPA antibodies). | Use an IHC-validated antibody for the paraffin-section comparison, and judge the result against HPA’s named positive and undetected cell populations (HPA antibodies; HPA tissue IHC). |
Experiment evidence
IHC & IF images showing PTN staining
A01368-2 · IHCIHC analysis of PTN using anti-PTN antibody (A01368-2). PTN was detected in a paraffin-embedded section of human glioma tissue. Heat mediate
A01368-2 · IHCIHC analysis of PTN using anti-PTN antibody (A01368-2). PTN was detected in a paraffin-embedded section of mouse brain tissue. Heat mediated
M01368 · IHCIHC analysis of PTN using anti-PTN antibody (M01368). PTN was detected in a paraffin-embedded section of mouse brain tissue. Heat mediated a
M01368 · IHCIHC analysis of PTN using anti-PTN antibody (M01368). PTN was detected in a paraffin-embedded section of rat brain tissue. Heat mediated ant
PA1414 · IHCIHC analysis of PTN using anti-PTN antibody (PA1414). PTN was detected in a paraffin-embedded section of human glioma tissue. Heat mediated
PA1414 · IHCIHC analysis of PTN using anti-PTN antibody (PA1414). PTN was detected in a paraffin-embedded section of human brain tissue. Heat mediated a
HPA · Pituitary glandHuman Protein Atlas IHC, Pituitary gland. Source: https://www.proteinatlas.org/ENSG00000105894-PTN/tissue/pituitary+gland#imid_924
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000105894-PTN/tissue/cerebral+cortex#imid_20295561
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000105894-PTN/tissue/colon#imid_20296343
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000105894-PTN/tissue/liver#imid_20296360
HPA · ICC-IF AF22Human Protein Atlas immunofluorescence, AF22, antibody HPA073913; green = PTN, blue = nucleus, red = microtubules.
HPA · ICC-IF AF22Human Protein Atlas immunofluorescence, AF22, antibody HPA073913; green = PTN, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for PTN IHC & IF
🧪Run cerebral cortex first and look for PTN staining in neuronal cells (HPA: High in cerebral-cortex neuronal cells); use adrenal gland glandular cells as the tissue negative (HPA: Not detected in adrenal-gland glandular cells). On the positive slide, putative internal-negative cells should retain counterstain without specific DAB signal, but confirm their identity independently because the supplied HPA row establishes neuronal-cell positivity only (HPA: High in cerebral-cortex neuronal cells).
Positive control tissue: Cerebral cortex (Neuronal cells, HPA High)
Negative control tissue: Adrenal gland (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show PTN in AF22, with annotated localisation: Endoplasmic reticulum (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control, a matched nonimmune rabbit IgG isotype control of the corresponding clonality, and PTN knockout material where available as a biological negative (selected-SKU caption: rabbit anti-PTN antibody; standard IHC practice). Quench endogenous peroxidase and check cerebral-cortex pigment background before scoring DAB staining (standard chromogenic IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A01368-2 paraffin-section caption does not state the fixative (selected-SKU caption: fixative not stated). Start with heat retrieval in EDTA at pH 8.0 as documented for this antibody, while treating retrieval dependence as unestablished; no supplied evidence shows that frozen sections or tissue IF are easier (selected-SKU caption: heat-mediated EDTA retrieval; HPA: AF22 ICC-IF images). In cerebral cortex, secreted PTN bound near cell surfaces may produce pericellular staining, so interpret signal near neurons with the controls rather than assuming it originates inside those cells (UniProt P21246: secreted; binds cell-surface proteoglycans).
HPA tissue IHC evidence for PTN
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — High consistency between antibody staining and RNA expression data. Secreted protein, tissue location of RNA and protein is expected to differ.). 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 |
|---|---|---|---|---|
| Cerebral cortex | Neuronal cells | High | Protein (IHC) | HPA → |
| Parathyroid gland | Glandular cells | High | Protein (IHC) | HPA → |
| Testis | Pachytene spermatocytes | High | Protein (IHC) | HPA → |
| Pituitary gland | Cells in anterior | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced PTN IHC Tips
Troubleshoot PTN staining in paraffin sections by checking retrieval, cellular context and controls before comparing chromogenic signal across samples.
What retrieval should I start with for PTN in paraffin sections?
Start with heat-mediated retrieval in EDTA at pH 8.0 (datasheet A01368-2). The documented human glioma section was incubated with 2 μg/ml antibody overnight at 4°C, so use that condition as a reference when assessing retrieval (datasheet A01368-2). Compare a retrieval-treated section with an otherwise matched section lacking retrieval, keeping section thickness, antibody incubation and DAB development constant (standard IHC practice). If staining remains weak, adjust heating duration on adjacent sections and assess whether tissue morphology deteriorates (standard IHC practice). Record both signal and damage, because stronger chromogen alone does not establish specific PTN detection (standard IHC practice).
How should I troubleshoot weak staining when the section fixative is uncertain?
PTN-specific sensitivity to fixation is unknown from the supplied evidence; the selected paraffin-section caption does not state its fixative (datasheet A01368-2). Record the actual fixative and fixation duration for each specimen before comparing staining across blocks (standard IHC practice). Run sections from the same block together using EDTA at pH 8.0 and the documented 2 μg/ml primary-antibody condition (datasheet A01368-2). If signals differ between blocks, check tissue preservation and processing records, then repeat with matched retrieval and detection conditions (standard IHC practice). Treat any proposed fixation effect as a hypothesis until it is tested on comparably processed material (standard IHC practice).
Should PTN staining be intracellular, extracellular or both?
Assess intracellular and extracellular staining separately: PTN is secreted and has no transmembrane segment (UniProt P21246 topology), while supported IF localisation is endoplasmic reticulum (HPA subcellular). HPA tissue IHC reports cytoplasmic staining in cerebral cortical neurons, spermatocytes and endocrine cells in parathyroid and pituitary glands (HPA tissue IHC). Cell-associated signal is therefore plausible, but extracellular staining may reflect secreted PTN binding cell-surface proteoglycans (UniProt P21246 function). Compare localisation with tissue architecture and a no-primary control on adjacent sections (standard IHC practice). Do not assign every stained cell as the producer of extracellular PTN; its secreted location can differ from the location of its RNA (HPA tissue IHC).
Could PTN processing or epitope accessibility explain discordant staining?
Check the antibody's stated immunogen or epitope before interpreting discordance; the supplied caption does not identify it (datasheet A01368-2). PTN is a 168-residue precursor with a signal peptide at residues 1–32 and a mature chain at 33–168 (UniProt P21246 processing). No isoforms or glycosylation sites are annotated in this record, so neither provides an evidenced explanation for differing patterns here (UniProt P21246 record). PTN binds proteoglycan-associated heparan or chondroitin sulfate chains, which makes access to extracellular antigen a reasonable question to test, not a demonstrated masking mechanism in these sections (UniProt P21246 interactions). Compare matched sections under documented retrieval and antibody conditions before attributing differences to epitope accessibility (datasheet A01368-2; standard IHC practice).
How can I check PTN localisation by multiplex IF alongside chromogenic IHC?
Use a PTN IF channel alongside a validated marker for the expected cell type, such as neuronal cells when examining cerebral cortex (HPA tissue IHC; standard IF practice). Choose spectrally separated fluorophores and inspect an unstained section in each channel to identify tissue autofluorescence before assigning PTN signal (standard IF practice). If the antibody epitope is intracellular, optimise gentle permeabilisation; if it is extracellular, compare staining without permeabilisation so surface-associated signal is preserved (UniProt P21246 topology; standard IF practice). The epitope location for A01368-2 is not supplied, and HPA reports supported endoplasmic-reticulum localisation by ICC/IF (datasheet A01368-2; HPA subcellular). Validate the IF antibody and conditions independently of the documented paraffin-section chromogenic protocol (datasheet A01368-2; standard IF practice).
What should I change when DAB signal appears diffuse across the section?
First inspect a no-primary section to separate detection-system background from primary-antibody-dependent staining (standard IHC practice). For HRP and DAB detection, include an endogenous-peroxidase block and keep DAB development matched across sections (standard IHC practice); the documented PTN image used an HRP-linked secondary system and DAB (datasheet A01368-2). The documented section was blocked with 10% goat serum before incubation with 2 μg/ml rabbit primary antibody overnight at 4°C (datasheet A01368-2). If diffuse staining persists, review washing, antibody concentration and section edges using matched controls (standard IHC practice). Because PTN is secreted, diffuse extracellular signal warrants localisation checks rather than automatic rejection as background (UniProt P21246 subcellular).
How should I score PTN staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the compartment and cell population before scoring, because PTN is secreted and HPA also reports cytoplasmic tissue staining (UniProt P21246 subcellular; HPA tissue IHC). For cell-associated DAB signal, record the percentage of positive cells and intensity by category, or calculate an H-score using percentage in each intensity category (standard IHC practice). For extracellular signal, measure positive area or optical density per tissue area, reported per mm², with consistent image acquisition and thresholds (standard IHC practice). Normalise cell counts to evaluable cells and area measurements to viable, analyzable tissue; exclude folds and necrosis by a prespecified rule (standard IHC practice). Keep retrieval and DAB development matched across sections, including EDTA at pH 8.0 for the documented antibody workflow (datasheet A01368-2; standard IHC practice).
How do I distinguish credible PTN signal from staining artefact?
Check whether staining occupies plausible cell-associated or extracellular locations: PTN is secreted, and HPA reports cytoplasmic staining in specific cell populations (UniProt P21246 subcellular; HPA tissue IHC). HPA reports high staining in cerebral cortical neurons, parathyroid glandular cells and pachytene spermatocytes, providing tissue and cell context for comparison (HPA tissue IHC). Be cautious with isolated nuclear-only staining, section-edge enhancement or staining confined to necrotic regions; compare adjacent morphology and a no-primary control (UniProt P21246 topology; standard IHC practice). If signal persists without primary antibody, investigate endogenous peroxidase or detection reagents before assigning it to PTN (standard IHC practice). Interpret extracellular signal cautiously because secreted PTN can bind cell-surface proteoglycans and need not identify its producing cell (UniProt P21246 function; HPA tissue IHC).
Boster reagents
Best PTN / Pleiotrophin IHC Antibodies
The catalog antibodies have paraffin-section IHC images from human glioma, human brain, mouse brain, and rat brain (catalog image captions). No IF/ICC image or validation is supplied (catalog applications and image captions).
Real IHC data
Anti-PTN Antibody ®
Cat # A01368-2
Real IHC data
Anti-Pleiotrophin Rabbit Monoclonal Antibody
Cat # M01368
Real IHC data
Anti-Pleiotrophin/PTN Antibody ®
Cat # PA1414
A01368-2 has paraffin-section IHC images from human glioma, mouse brain, and rat brain; M01368 has images from mouse and rat brain (each SKU’s IHC image captions). PA1414 has paraffin-section IHC images from human glioma and human brain (PA1414 IHC image captions).
Which to pick: For tissue IHC, choose the rabbit monoclonal M01368 for mouse or rat brain sections, or A01368-2 and PA1414 for the pictured human tissues; each caption documents paraffin sections with EDTA retrieval at pH 8.0, while the fixative is unreported (catalog antibody details; each SKU’s IHC image captions). For cross-species IHC, A01368-2 has the broadest pictured coverage—human, mouse, and rat—and lists reactivity with all three (A01368-2 IHC image captions; catalog reactivity). No listed SKU is validated for IF/ICC, so select an IF/ICC-validated antibody for that application (catalog applications and IF image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P21246 (PTN_HUMAN, Pleiotrophin).
- Human Protein Atlas. PTN tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. PTN subcellular location (ICC-IF): Localized to the endoplasmic reticulum..
- Human Protein Atlas. PTN antibody validation summary (2 antibodies).
- Increased Pleiotrophin Concentrations in Papillary Thyroid Cancer. PloS one 2016 — PMC4767803.
- Pleiotrophin and N-syndecan promote perineural invasion and tumor progression in an orthotopic mouse model of pancreatic cancer. World journal of gastroenterology 2017 — PMC5467077.
- Pleiotrophin in Mammary Gland Development and Breast Cancer: A Comprehensive Review of the Evidence. Cells 2026 — PMC13204032.
- Expression of the pleiotrophin-midkine axis in a sheep tooth socket model of bone healing. Journal of periodontal research 2023 — PMC10099163.
- PubMed PMID:1701634 — UniProt-cited evidence.
- PubMed PMID:2270483 — UniProt-cited evidence.
- PubMed PMID:1768439 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for PTN (Pleiotrophin). Expected localisation Observed cytoplasmic staining (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A01368-2). Validated IHC antibody: A01368-2 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Cerebral cortex (Neuronal cells); negative Adrenal gland. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human glioma tissue; fixative not specified (datasheet A01368-2); 2. Fixation: Image fixative and duration unreported (datasheet A01368-2); 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 A01368-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A01368-2); 8. Primary antibody: Rabbit anti-PTN, 2-5 μg/ml (datasheet A01368-2); 9. Primary incubation: Overnight at 4 °C (datasheet A01368-2). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Caveat: Secreted PTN binds cell-surface proteoglycans (UniProt); Isoform / epitope: No isoforms annotated; mature chain spans residues 33–168 (UniProt); Regulation: Expression induction is unspecified (UniProt). Evidence: UniProt P21246, HPA tissue IHC · Enhanced, HPA ICC-IF · endoplasmic reticulum., Datasheet A01368-2, PMC4767803, PMC5467077. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/PTN/immunohistochemistry-ihc-guide.