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EI24 / Etoposide-induced protein 2.4 homolog · IHC design guide
Design Immunohistochemistry for EI24
Plan EI24 chromogenic IHC-P using the cytoplasmic pattern in most tissues and membranous staining in parathyroid glandular cells (HPA tissue IHC). The catalog antibody starts at 5 μg/mL in rat IHC; optimize it for human sections (datasheet: rat IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
EI24 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 | Mostly cytoplasmic; parathyroid membranous (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic in most tissues; membranous in parathyroid glandular cells (HPA tissue IHC) | |
| Antigen retrieval | Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen) | |
| Positive control | Parathyroid gland+4 more · see all | |
| Negative control | Adipose tissue+3 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 | Antibody staining has low consistency with RNA expression (HPA tissue IHC) | |
| Regulation | p53-mediated apoptosis role; staining induction unknown (UniProt) | |
| Isoform / epitope | 2 isoforms; epitope differences and membrane side unknown (UniProt) |
Section 1
Recommended EI24 IHC & IF Protocols
The catalog antibody's IHC-P protocol is accompanied by published EI24 IHC methods for breast, esophageal and pancreatic cancer specimens (PMC13489907; PMC7471874; PMC6189671; PMC5386697).
| Sample | Tissue sections; selected-image fixative not specified (standard IHC workflow) |
| Fixation | Image fixative and duration unreported (datasheet A06183); 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 Tris-EDTA buffer, pH 9.0, 20 min at 95–98 °C (standard rule: nuclear antigen) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% normal serum of the secondary host, 30 min, room temperature (standard) |
| Primary antibody | Rabbit anti-EI24, 5 μg/mL (datasheet A06183) |
| 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 | EI24-positive staining in glandular cells of parathyroid gland (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in most tissues. Membranous expression in parathyroid gland. No signal in the no-primary control. |
💡Decision noteStart with Tris-EDTA pH 9.0 retrieval at 95–98 °C for 20 min (page retrieval setting), then assess staining in the intended tissue.
Section 2
What Is the Expected EI24 Staining Pattern?
EI24 staining is predominantly cytoplasmic across most tissues, with membranous staining reported in parathyroid glandular cells (HPA tissue IHC). Expect strong staining in parathyroid glandular cells and elongated or late spermatids (HPA: High). EI24 has five transmembrane segments and is annotated at the endoplasmic reticulum and nuclear membranes and in the cytoplasm (UniProt O14681 topology and subcellular location). HPA rates its tissue IHC evidence Approved, while reporting low consistency with RNA expression (HPA tissue IHC).
| Strong glandular staining in parathyroid, with a membranous pattern (HPA: High; membranous expression). | This matches a documented positive tissue and compartment. Compare staining with the glandular cells on the same section; a strong signal alone is less informative if its cellular pattern is unclear (HPA tissue IHC). |
| Cytoplasmic staining in other tissues, or strong staining in elongated or late spermatids (HPA tissue IHC). | Cytoplasmic staining fits HPA's pattern across most tissues; the spermatids provide another reported strong positive population (HPA: High). Score identifiable cells and their compartment rather than treating all staining on the slide as equivalent. |
| Predominantly nuclear staining where the expected cytoplasmic or parathyroid membranous pattern is absent (HPA tissue IHC). | Treat this as a pattern mismatch requiring investigation, not confirmed EI24 localization. UniProt annotates the nuclear membrane, but that annotation does not establish diffuse nuclear IHC staining (UniProt O14681 subcellular location). |
| Strong signal in adipocytes, marrow hematopoietic cells, chondrocytes or splenic red-pulp cells (HPA: Not detected). | These are reported negative cell populations. Check morphology and controls for cross-reactivity or endogenous detection activity before calling the signal EI24; HPA's negative observations are reference patterns, not proof that every specimen must be blank. |
| Diffuse stain across cells and tissue spaces, or no signal in parathyroid glandular cells (HPA: High). | Diffuse stain obscures compartment and cell-type assessment and calls for a background check. An absent signal in a reported strong positive calls for review of the IHC workflow and control section before interpreting other negative areas. |
💡Expected EI24 appearanceCall a section positive when identifiable cells show mainly cytoplasmic staining, with strong signal in parathyroid glandular cells that may appear membranous or in elongated or late spermatids (HPA tissue IHC); widespread featureless stain or strong signal restricted to HPA-negative cell populations warrants review.
| Subcellular reference pattern | HPA reports mainly cytoplasmic tissue staining and membranous staining in parathyroid gland (HPA tissue IHC). UniProt lists cytoplasm and endoplasmic reticulum and nuclear membranes, with five transmembrane segments (UniProt O14681); these annotations do not predict a uniquely visible membrane outline in every section. |
| Tissue and cell selection | Parathyroid glandular cells and elongated or late spermatids are reported High; several other listed cell populations are Medium (HPA tissue IHC). Select and score the named cells within each tissue. A tissue name alone does not establish that every cell should stain. |
| Strength of HPA tissue evidence | The tissue IHC profile is Approved, with low consistency between antibody staining and RNA expression (HPA tissue IHC). Treat the documented protein staining as a useful visual reference, while checking unexpected results with appropriate controls rather than claiming RNA agreement. |
| Antibody-specific validation | HPA047165 and HPA051029 each have Approved IHC status; only HPA051029 has Supported ICC status (HPA antibodies). Those classifications apply to the listed antibodies. They do not establish that an unlisted antibody will reproduce either staining pattern. |
| Assay and preparation | HPA's ICC-IF summary places EI24 mainly in cytosol, with additional endoplasmic reticulum and Golgi localization (HPA subcellular ICC-IF). That cellular image reference can inform a localization question, but tissue IHC remains the reference for scoring a paraffin section; no ICC-IF protocol is specified here. |
| Protein forms and fixation evidence | UniProt lists two isoforms, no signal peptide or propeptide, and no annotated glycosylation sites (UniProt O14681). These facts do not identify the antibody epitope or establish differential staining. Target-specific fixation sensitivity is unreported in the supplied sources. |
| Situation | Likely cause | Next action |
|---|---|---|
| Parathyroid glandular cells lack the expected strong signal (HPA: High). | The reference positive has failed, or the sampled section does not show comparable glandular cells; the supplied sources do not identify an EI24-specific fixation cause. | Confirm cell morphology and the positive control, then review the antibody's IHC-P instructions and routine retrieval, dilution and detection steps. Record any optimization as assay-specific rather than an established EI24 fixation effect. |
| Signal is diffuse, with no readable cellular boundary or cytoplasmic distribution. | General IHC background can arise from nonspecific binding or the detection system; diffuse staining alone does not establish EI24 localization. | Compare with a no-primary control and inspect blocking, washing and chromogen development. Reassess the specimen only after cell outlines and the expected compartment can be distinguished. |
| Strong stain appears in a reported negative cell population (HPA: Not detected). | Cross-reactivity or endogenous detection activity is possible; a single discordant cell population cannot identify which mechanism is responsible. | Check a no-primary control and cell morphology. For an enzyme-based chromogen, review the relevant endogenous-enzyme blocking step; if signal persists, assess antibody specificity with an independent suitable control. |
| Staining is predominantly diffuse nuclear rather than cytoplasmic or parathyroid membranous (HPA tissue IHC). | The compartment differs from the tissue reference. UniProt's nuclear-membrane annotation does not by itself explain staining throughout the nucleus (UniProt O14681). | Inspect counterstain and optical focus to verify the compartment, then compare a known-positive section and detection controls before assigning the nuclear signal to EI24. |
| A parathyroid section shows staining, but glandular cells lack the expected membranous emphasis (HPA tissue IHC). | The observed pattern differs from HPA's parathyroid description; intensity alone cannot settle localization, and the sources do not establish a target-specific preparation cause. | Score glandular cells separately from adjacent tissue, check section quality and control staining, and document the actual compartment instead of forcing a positive-pattern call. |
| ICC-IF shows cytosol plus organelle signal, while the paraffin IHC section looks mainly cytoplasmic. | These are distinct assay readouts: HPA reports cytosol as the main ICC-IF location, with additional endoplasmic reticulum and Golgi signal (HPA subcellular ICC-IF). | Use the tissue IHC pattern to interpret the paraffin section and the ICC-IF record for its own localization question. Do not treat an ICC-IF organelle pattern as an IHC-P scoring requirement. |
Experiment evidence
IHC & IF images showing EI24 staining
A06183 · IHCImmunohistochemistry of EI24 in rat liver tissue with EI24 antibody at 5 μg/mL.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000149547-EI24/tissue/cerebral+cortex#imid_13141706
HPA · Parathyroid glandHuman Protein Atlas IHC, Parathyroid gland. Source: https://www.proteinatlas.org/ENSG00000149547-EI24/tissue/parathyroid+gland#imid_13141975
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000149547-EI24/tissue/colon#imid_13141936
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000149547-EI24/tissue/liver#imid_13141911
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA051029; green = EI24, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA051029; green = EI24, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for EI24 IHC & IF
🧪Run parathyroid gland first and require staining in its glandular cells (HPA: High in parathyroid glandular cells). Use adipose tissue as the negative tissue, with adipocytes lacking detectable staining (HPA: Not detected in adipocytes); assess other cells on the parathyroid slide for background, but the supplied HPA row does not establish an internal negative cell type (HPA: parathyroid glandular cells High).
Positive control tissue: Parathyroid gland (Glandular cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show EI24 in A-431, HEK293, U2OS, KOLF2.1J, with annotated localisation: Cytosol (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control; a host-species- and isotype-matched control for a monoclonal primary, or matched normal IgG for a polyclonal primary; and EI24 knockout material or a peptide-blocking control if the immunizing peptide is available (standard IHC practice). Quench endogenous peroxidase for chromogenic detection, and control endogenous biotin if using a biotin-based detection system (standard IHC practice).
⚠️Feasibility: An EI24-specific fixation window and antigen-retrieval dependence are unreported in the supplied evidence; optimize retrieval on paraffin sections using the positive and negative controls (standard IHC practice). The selected A06183 rat-liver IHC caption reports 5 μg/mL but does not report a fixative (selected SKU A06183 caption). These data do not establish whether frozen sections or IF/ICC would be easier, and they identify no parathyroid-specific artefact (HPA: parathyroid glandular cells High; HPA: ICC-IF subcellular images).
HPA tissue IHC evidence for EI24
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Low 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 |
|---|---|---|---|---|
| Parathyroid gland | Glandular cells | High | Protein (IHC) | HPA → |
| Testis | Elongated or late spermatids | High | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Medium | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Medium | Protein (IHC) | HPA → |
| Breast | 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 → |
| Soft tissue | Chondrocytes | Not detected | Protein (IHC) | HPA → |
| Spleen | Cells in red pulp | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced EI24 IHC Tips
Troubleshoot EI24 staining in paraffin sections by checking retrieval, tissue controls, compartment patterns and scoring before interpreting chromogenic signal.
What retrieval conditions should I start with for EI24 paraffin-section IHC?
Start with Tris-EDTA at pH 9.0 for heat-induced epitope retrieval at 95–98 °C for 20 min (page retrieval setting: nuclear-antigen rule). Let sections cool in retrieval buffer, then compare a known positive control across runs using the same heating vessel and detection conditions (standard IHC practice; HPA: high staining in parathyroid glandular cells). If staining is weak, test a different retrieval buffer on adjacent sections while keeping the antibody concentration and development time fixed (standard IHC practice). EI24 has 5 annotated transmembrane segments, so retrieval success should be judged by specific cellular staining rather than nuclear staining alone (UniProt O14681 topology; HPA tissue IHC: predominantly cytoplasmic expression).
How should I troubleshoot weak EI24 staining after fixation?
EI24-specific sensitivity to fixative type or fixation duration is unknown from the supplied evidence; the selected rat liver IHC caption does not state a fixative (A06183 tissue-IHC caption). Record fixation conditions for each block and compare matched sections processed with the same retrieval, antibody concentration and detection time (standard IHC practice). If signal varies across batches, include the same positive control in each run before attributing the difference to EI24 abundance (standard IHC practice; HPA: high staining in parathyroid glandular cells). Examine morphology and section edges for uneven processing, and change 1 preparation variable at a time (standard IHC practice).
Which EI24 staining pattern is plausible in chromogenic tissue sections?
Assess cytoplasmic staining first: tissue IHC reports cytoplasmic expression in most tissues and membranous expression in parathyroid gland (HPA tissue IHC). EI24 is also annotated at the endoplasmic reticulum membrane, nuclear membrane and in the cytoplasm, with 5 transmembrane segments (UniProt O14681 subcellular location and topology). A perinuclear or membrane-associated pattern can therefore warrant investigation, but chromogenic resolution alone cannot assign staining to a specific organelle (UniProt O14681 subcellular location; standard IHC practice). Compare cell type and compartment against a positive tissue control and a no-primary control before accepting an unexpected nuclear or diffuse pattern (HPA tissue IHC; standard IHC practice).
Could EI24 isoforms or epitope accessibility explain discordant IHC results?
EI24 has 2 annotated isoforms and 5 transmembrane segments, so confirm which sequence region the IHC-validated antibody recognizes before comparing staining across studies (UniProt O14681 isoforms and topology; standard IHC practice). The supplied evidence does not map this antibody’s epitope to an isoform or a membrane-facing region (supplied A06183 caption; UniProt O14681 record). Phosphorylation is annotated at residues 46, 47, 56 and 320, but its effect on this antibody’s IHC signal is unestablished (UniProt O14681 modified residues; supplied A06183 caption). If results disagree, compare antibody epitope documentation, retrieval conditions and matched positive controls before assigning an isoform-specific explanation (standard IHC practice).
How can IF help assess an ambiguous EI24 chromogenic pattern?
Use IF as a separate validation experiment and multiplex EI24 with a validated marker of the expected cell type, such as parathyroid glandular cells in a suitable specimen (HPA tissue IHC: high staining in parathyroid glandular cells; standard IF practice). Choose spectrally separated fluorophores after inspecting tissue autofluorescence, and include single-label and no-primary controls to check bleed-through and background (standard IF practice). EI24 has 5 transmembrane segments; select permeabilisation based on which side of the membrane contains the antibody epitope, if known (UniProt O14681 topology; standard IF practice). Compare the resulting compartment pattern with chromogenic IHC cautiously because the two detection methods resolve subcellular detail differently (standard IHC/IF practice).
What should I check when EI24 IHC has diffuse background?
Run a no-primary control alongside the tissue and inspect whether the same diffuse deposit remains (standard IHC practice). For peroxidase-based chromogenic detection, verify the endogenous peroxidase block and shorten DAB development if the control also darkens (standard IHC practice). If background appears only with primary antibody, titrate its concentration, strengthen appropriate protein blocking and check wash consistency on matched sections (standard IHC practice). The selected rat liver image used antibody at 5 µg/mL, but its caption supplies neither fixative nor background controls, so treat that concentration as a reported example rather than a universal optimum (A06183 tissue-IHC caption).
How should I quantify EI24 staining across tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring, then use an H-score from intensity and percentage of positive cells or report percentage positive cells separately (standard IHC scoring practice). For sparse populations, positive-cell density per mm² may be more informative than a whole-section average (standard IHC scoring practice). Normalize counts to the number of evaluable target cells or measured viable tissue area, and keep retrieval, imaging and threshold settings constant across samples (standard IHC scoring practice). Report compartments separately where relevant, because HPA describes predominantly cytoplasmic tissue staining but membranous staining in parathyroid gland (HPA tissue IHC).
When should an apparent EI24-positive signal be treated as artefact?
Treat a signal cautiously when it appears chiefly at section edges, in necrotic areas or in the no-primary control; these patterns can reflect processing or detection artefacts (standard IHC practice). Check endogenous enzyme activity when using peroxidase and DAB detection, especially if the no-primary control develops color (standard IHC practice). Compare cell identity with HPA patterns: parathyroid glandular cells and late spermatids are reported high, whereas adipocytes are reported not detected (HPA tissue IHC). An isolated nuclear-only pattern needs further validation because tissue IHC is predominantly cytoplasmic, although EI24 also has a nuclear-membrane annotation (HPA tissue IHC; UniProt O14681 subcellular location).
Boster reagents
Best EI24 / Etoposide-induced protein 2.4 homolog IHC Antibodies
One anti-EI24 antibody has real IHC data from rat liver tissue (catalog image caption); human and mouse reactivity is listed, but IHC validation is reported only in rat samples (catalog datasheet).
Real IHC data
Anti-EI24 Antibody
Cat # A06183
A06183 will render with an IHC image of rat liver tissue stained at 5 μg/mL (catalog image caption). Its listed applications include IHC-P, and its listed reactivity covers human, mouse and rat (catalog application and reactivity lists).
Which to pick: Choose A06183 for paraffin-section IHC: IHC-P is listed, and its own image shows rat liver staining at 5 μg/mL (catalog application list; catalog image caption). The image caption does not report the fixative or tissue processing, and clonality is unreported (catalog image caption; catalog clone field). For IF/ICC or human or mouse IHC, no validation is shown; A06183 lists human and mouse reactivity but provides neither an IF application nor IF data (catalog application and reactivity lists; catalog image fields).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O14681 (EI24_HUMAN, Etoposide-induced protein 2.4 homolog).
- Human Protein Atlas. EI24 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. EI24 subcellular location (ICC-IF): Mainly localized to the cytosol. In addition localized to the Golgi apparatus and endoplasmic reticulum..
- Human Protein Atlas. EI24 antibody validation summary (2 antibodies).
- EI24 suppresses TNBC tumorigenesis by regulating AKT signaling. Frontiers in oncology 2026 — PMC13489907.
- EI24 Inhibits Cell Proliferation and Drug Resistance of Esophageal Squamous Cell Carcinoma. Frontiers in oncology 2020 — PMC7471874.
- EI24 Suppresses Tumorigenesis in Pancreatic Cancer via Regulating c-Myc. Gastroenterology research and practice 2018 — PMC6189671.
- MicroRNA-455-3p promotes invasion and migration in triple negative breast cancer by targeting tumor suppressor EI24. Oncotarget 2017 — PMC5386697.
- PubMed PMID:9305847 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for EI24 (Etoposide-induced protein 2.4 homolog). Expected localisation Mostly cytoplasmic; parathyroid membranous (HPA tissue IHC). Antigen retrieval: Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen). Validated IHC antibody: A06183 at 5 μg/mL (the product's own IHC validation image is shown). Controls (HPA): positive Parathyroid gland (Glandular cells); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Tissue sections; selected-image fixative not specified (standard IHC workflow); 2. Fixation: Image fixative and duration unreported (datasheet A06183); 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 Tris-EDTA buffer, pH 9.0 , 20 min at 95–98 °C…; 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% normal serum of the secondary host, 30 min , room temperature (standard); 8. Primary antibody: Rabbit anti-EI24, 5 μg/mL (datasheet A06183); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections. (standard IHC practice; not target-specific); Caveat: Antibody staining has low consistency with RNA expression (HPA tissue IHC); Isoform / epitope: 2 isoforms; epitope differences and membrane side unknown (UniProt); Regulation: p53-mediated apoptosis role; staining induction unknown (UniProt). Evidence: UniProt O14681, HPA tissue IHC · Approved, HPA ICC-IF · Mainly localized to the cytosol. In addition localized to the Golgi…, Datasheet A06183, PMC13489907, PMC7471874. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/EI24/immunohistochemistry-ihc-guide.