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AGR2 / Anterior gradient protein 2 homolog · IHC design guide
Design Immunohistochemistry for AGR2
This AGR2 paraffin IHC guide focuses on cytoplasmic staining in glandular tissues (HPA tissue IHC). Use bronchial respiratory epithelium as a positive control and adipocytes as a negative control (HPA tissue IHC); titrate the catalog antibody at 2–5 μg/ml (datasheet A02922-2).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
AGR2 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 staining in glandular tissues (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic staining in glandular and urothelial epithelia (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A02922-2) | |
| 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 samples (standard IHC practice; not target-specific) | |
| Caveat | Secreted AGR2 may stain beyond producer cells (UniProt) | |
| Regulation | Enhanced RNA in cervix, intestine, stomach (HPA tissue RNA) | |
| Isoform / epitope | No isoforms annotated; mature chain excludes signal peptide (UniProt) |
Section 1
Recommended AGR2 IHC & IF Protocols
The catalog antibody uses heat-mediated EDTA pH 8.0 retrieval (datasheet A02922-2). Four published AGR2 IHC protocols cover human and canine tumor tissue (PMC4496185; PMC2361240; PMC8460385; PMC8532596).
| Sample | Paraffin-embedded human colorectal adenocarcinoma tissue; fixative not specified (datasheet A02922-2) |
| Fixation | Image fixative and duration unreported (datasheet A02922-2); 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 A02922-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A02922-2) |
| Primary antibody | Rabbit anti-AGR2, 2-5μg/ml (datasheet A02922-2) |
| Primary incubation | Overnight at 4 °C (datasheet A02922-2) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A02922-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | AGR2-positive staining in endocrine cells of appendix (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in glandular tissues, including glands in GI, female and male genitalia, and urothelial epithelia. No signal in the no-primary control. |
💡Decision noteStart with EDTA pH 8.0 for the catalog antibody (datasheet A02922-2). Use citrate pH 6.0 when reproducing protocols that specify it (PMC4496185; PMC8460385).
Section 2
What Is the Expected AGR2 Staining Pattern?
AGR2 is secreted and also localizes to the endoplasmic reticulum; it has no transmembrane segment (UniProt O95994). In paraffin-section IHC, expect chiefly cytoplasmic staining in glandular and other listed epithelial cells (HPA tissue IHC: Enhanced reliability; medium consistency with RNA). Endoplasmic reticulum localization is supported separately by ICC-IF (HPA subcellular). Interpret the pattern by cell type and compartment, since staining strength varies across the listed tissues (HPA tissue IHC).
| Clear cytoplasmic staining in cervical or endometrial glandular cells, or bronchial respiratory epithelial cells (HPA tissue IHC: High). | This matches the reported IHC distribution (HPA tissue IHC). Score the relevant cells and their cytoplasm; staining elsewhere in the section should be assessed separately (standard IHC practice). HPA’s Enhanced tissue rating carries a medium RNA–staining consistency caveat, so the pattern supports interpretation without proving specificity in every specimen (HPA tissue IHC). |
| Predominantly nuclear staining with little cytoplasmic signal in an expected positive cell population (HPA tissue IHC; HPA subcellular). | A nuclear-dominant result conflicts with reported cytoplasmic tissue staining and supported endoplasmic reticulum localization (HPA tissue IHC; HPA subcellular). Treat it as suspect, then compare with an expected positive tissue and detection controls before assigning AGR2 expression (standard IHC practice). |
| Strong staining in esophageal squamous epithelial cells or heart cardiomyocytes (HPA tissue IHC: Not detected). | This is outside those cell types’ reported HPA pattern (HPA tissue IHC). Check whether staining persists in a no-primary control; persistence suggests endogenous detection activity or background, while primary-dependent staining warrants a specificity check (standard IHC practice). |
| Broad, low-contrast color across tissue and surrounding areas, without a clear cytoplasmic cell pattern (HPA tissue IHC). | The result cannot be scored confidently against the reported cell-restricted cytoplasmic pattern (HPA tissue IHC). Compare a no-primary control and review blocking, washing, detection and counterstain conditions for nonspecific signal (standard IHC practice). |
| No staining in bronchial respiratory epithelium or cervical glandular cells expected to stain strongly (HPA tissue IHC: High). | A negative result in an expected positive cell population raises a run-performance question before it supports biological absence (HPA tissue IHC; standard IHC practice). Verify that the positive cells are present, then review the catalog antibody’s IHC-P conditions and the detection controls (standard IHC practice). |
💡Expected AGR2 appearanceCall an IHC result consistent with AGR2 when listed positive glandular or respiratory epithelial cells show distinct cytoplasmic staining, potentially strong in HPA High cell populations; nuclear-dominant or widespread staining in HPA Not detected cell types is suspect (HPA tissue IHC; HPA subcellular).
| Cell-specific tissue distribution (HPA tissue IHC). | High staining is reported in cervical, endometrial, epididymal and fallopian-tube glandular cells, bronchial respiratory epithelial cells, and appendix, colon and duodenum endocrine cells (HPA tissue IHC). Interpret the named cell population, not the tissue label alone (standard IHC practice). |
| Low and absent comparison sites (HPA tissue IHC). | Kidney distal tubules and breast glandular cells are listed as low, whereas adipocytes and esophageal squamous epithelial cells are Not detected (HPA tissue IHC). A weak kidney or breast result is therefore less decisive as a run control than an HPA High cell population (HPA tissue IHC; standard IHC practice). |
| Localization and topology (UniProt O95994; HPA subcellular). | UniProt lists AGR2 as secreted and endoplasmic reticulum localized, with no transmembrane segment; HPA supports endoplasmic reticulum localization by ICC-IF (UniProt O95994; HPA subcellular). These records support a cytoplasmic tissue pattern and do not establish a membrane-staining requirement (HPA tissue IHC; UniProt O95994). |
| Processing and antibody evidence (UniProt O95994; HPA antibodies). | UniProt records a signal peptide at residues 1–20 and a chain spanning 21–175; no epitope is supplied, so the effect of processing on this antibody’s IHC signal is undetermined (UniProt O95994). HPA007912 has Enhanced IHC validation, which supports its reported pattern without establishing performance in every preparation (HPA antibodies). |
| IF/ICC expectation? (HPA subcellular; HPA antibodies). | For the separate IF/ICC guide, expect endoplasmic reticulum localization: HPA calls it supported and lists A-549, RT-4 and U2OS ICC-IF images (HPA subcellular). HPA007912 is Approved for ICC; that status does not supply an IF/ICC protocol here (HPA antibodies). |
| Situation | Likely cause | Next action |
|---|---|---|
| No signal in an expected positive IHC section (HPA tissue IHC: High). | The target cell population may be absent from the viewed area, or the IHC run may have failed (standard IHC practice). | Find the named positive cells on the section; check a positive run control, reagent sequence and the catalog antibody’s IHC-P conditions before scoring the specimen negative (HPA tissue IHC; standard IHC practice). |
| Weak signal in kidney distal tubules or breast glandular cells (HPA tissue IHC: Low). | Low staining is reported for those cell populations, so weak signal alone need not indicate a failed assay (HPA tissue IHC). | Compare with a High population, such as bronchial respiratory epithelial or cervical glandular cells, under the same run conditions before changing detection settings (HPA tissue IHC; standard IHC practice). |
| Nuclear-dominant color in otherwise positive cells (HPA tissue IHC; HPA subcellular). | The compartment disagrees with HPA’s cytoplasmic tissue profile and supported endoplasmic reticulum localization; the supplied records do not identify a specific technical cause (HPA tissue IHC; HPA subcellular). | Check a no-primary control, inspect the counterstain and compare the cytoplasmic pattern in a known positive tissue before interpreting nuclear color as AGR2 (standard IHC practice). |
| Color in HPA Not detected cell types, such as adipocytes or esophageal squamous epithelium (HPA tissue IHC). | Possible explanations include background, endogenous detection activity or primary-antibody cross-reactivity; the image alone cannot distinguish them (standard IHC practice). | Run a no-primary control and compare its distribution with the test slide; if staining depends on the primary antibody, reassess specificity using the expected positive and negative cell patterns (HPA tissue IHC; standard IHC practice). |
| Diffuse color obscures cell boundaries and compartments (HPA tissue IHC). | Excess nonspecific staining or detection background can obscure the expected cytoplasmic, cell-specific pattern (HPA tissue IHC; standard IHC practice). | Review blocking, washes, primary-antibody dilution and detection conditions against the catalog IHC-P protocol; use a no-primary control to locate background from the detection steps (standard IHC practice). |
| Different apparent positivity across two glandular tissues (HPA tissue IHC). | HPA reports High, Low and Not detected staining by specified cell population, and its tissue IHC reliability notes medium consistency with RNA (HPA tissue IHC). | Identify and score the relevant cell types in each section, then compare their reported HPA levels; do not treat a whole-tissue difference alone as proof of an antibody problem (HPA tissue IHC; standard IHC practice). |
Experiment evidence
IHC & IF images showing AGR2 staining
A02922-2 · IHCIHC analysis of AGR2 using anti-AGR2 antibody (A02922-2). AGR2 was detected in a paraffin-embedded section of human colorectal adenocarcinom
A02922-2 · IHCIHC analysis of AGR2 using anti-AGR2 antibody (A02922-2). AGR2 was detected in a paraffin-embedded section of human non-small cell lung canc
M02922 · IHCImmunohistochemical analysis of paraffin-embedded human uterus, using AGR2 Antibody.
M02922 · IFImmunofluorescent analysis using the Antibody at 1:50 dilution.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000106541-AGR2/tissue/cerebral+cortex#imid_2718612
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000106541-AGR2/tissue/colon#imid_2718554
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000106541-AGR2/tissue/liver#imid_2718555
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000106541-AGR2/tissue/kidney#imid_2718556
HPA · ICC-IF A-549Human Protein Atlas immunofluorescence, A-549, antibody HPA007912; green = AGR2, blue = nucleus, red = microtubules.
HPA · ICC-IF A-549Human Protein Atlas immunofluorescence, A-549, antibody HPA007912; green = AGR2, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for AGR2 IHC & IF
🧪Run bronchus first and look for staining in respiratory epithelial cells (High; HPA: bronchus), then use adipose tissue adipocytes as a negative comparator (HPA: Not detected in adipocytes). On the bronchus slide, morphologically distinct non-target cells should show background-only signal, without specific chromogen deposition; the supplied HPA row does not establish their AGR2 status (HPA: High in respiratory epithelial cells).
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 AGR2 in A-549, RT-4, U2OS, with annotated localisation: Endoplasmic reticulum (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control; an isotype control matched to the rabbit primary’s class and clonality; and AGR2 knockout material or a validated peptide-block control (selected-SKU caption: rabbit anti-AGR2). Quench endogenous peroxidase and check for background in bronchus before interpreting DAB staining (selected-SKU caption: HRP/DAB detection).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the exact A02922-2 tissue-IHC caption does not report a fixative (selected-SKU caption: fixative not stated). That caption reports heat retrieval in EDTA at pH 8.0 for a colorectal adenocarcinoma paraffin section; retrieval in bronchus needs optimization (selected-SKU caption: EDTA retrieval). HPA supports ER localisation by ICC-IF, but the supplied evidence does not establish that IF or frozen sections are easier than paraffin IHC; assess bronchial mucus for nonspecific background (HPA: endoplasmic reticulum, supported; HPA: High in bronchial respiratory epithelial cells).
HPA tissue IHC evidence for AGR2
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 → |
| Bronchus | Respiratory epithelial cells | High | Protein (IHC) | HPA → |
| Cervix | Glandular cells | High | Protein (IHC) | HPA → |
| Colon | Endocrine cells | High | Protein (IHC) | HPA → |
| Duodenum | 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 AGR2 IHC Tips
Troubleshoot AGR2 staining in paraffin-section chromogenic IHC by checking retrieval, staining controls, cellular localisation and scoring consistency.
Which retrieval condition should I start with for weak AGR2 staining?
Start with heat-mediated EDTA retrieval at pH 8.0 for paraffin-section AGR2 IHC (datasheet A02922-2). The selected image used that condition before staining human colorectal adenocarcinoma with 2 μg/ml primary antibody overnight at 4°C (caption A02922-2). If staining is weak, check heating consistency and section adhesion, then compare retrieval durations on adjacent sections while keeping antibody concentration and detection constant (standard IHC practice). Include a no-primary control to reveal detection background, and compare the resulting glandular cytoplasmic pattern with the reported AGR2 tissue profile (standard IHC practice; HPA tissue IHC). The caption does not specify a retrieval duration, so it cannot establish an optimal time (caption A02922-2).
Could fixation explain weak or uneven AGR2 staining?
The selected paraffin-section caption does not state its fixative, so AGR2-specific fixation sensitivity remains unknown (caption A02922-2). For a general IHC starting condition, document tissue thickness and fixation in 10% neutral buffered formalin, then apply the same schedule across comparison specimens (standard IHC practice). If staining varies between sections, review fixation records alongside processing, retrieval and section age before assigning the difference to AGR2 expression (standard IHC practice). Compare adjacent sections under one EDTA pH 8.0 retrieval condition and one antibody concentration to isolate the source of variation (datasheet A02922-2; standard IHC practice). HPA staining patterns do not establish this antibody’s fixation tolerance (HPA tissue IHC).
Where should convincing AGR2 staining appear in tissue sections?
Expect predominantly cytoplasmic staining in glandular tissues, including gastrointestinal and genital glandular epithelia (HPA tissue IHC). AGR2 is reported in the endoplasmic reticulum and is also secreted, so a cytoplasmic signal is compatible with its biology (HPA subcellular; UniProt O95994 subcellular). For an on-slide reference, assess epithelial cells before interpreting weaker staining in surrounding structures; respiratory epithelium and cervical glandular cells have reported high expression (HPA tissue IHC). A nucleus-only pattern warrants scrutiny because the supported subcellular location is the endoplasmic reticulum (HPA subcellular). Compare stained and no-primary serial sections at the same exposure or viewing settings before accepting faint diffuse signal (standard IHC practice).
How could epitope placement affect AGR2 IHC interpretation?
AGR2 is annotated as a 175-residue precursor with a signal peptide at residues 1–20 and a mature chain at 21–175 (UniProt O95994 processing). The record annotates no transmembrane segment, glycosylation sites or isoforms; these annotations do not identify the catalog antibody’s epitope (UniProt O95994 topology, glycosylation and isoforms; caption A02922-2). Ask for the immunogen or epitope region before attributing absent staining to processing or an isoform (standard IHC practice). A signal-peptide epitope could behave differently from one in the mature chain after processing (UniProt O95994 processing; standard protein biology). Validate any proposed epitope explanation with independent staining evidence rather than intensity alone (standard IHC practice).
How should I evaluate AGR2 by multiplex immunofluorescence?
For IF, pair AGR2 with a marker that identifies the expected epithelial or glandular cells, then assess whether the signals occur in the same cells (HPA tissue IHC; standard IF practice). Choose a fluorophore channel after measuring tissue autofluorescence and include single-stain controls to assess spectral bleed-through (standard IF practice). AGR2 has a signal peptide, no annotated transmembrane segment and a supported endoplasmic-reticulum location, so permeabilisation should allow antibody access to intracellular AGR2 (UniProt O95994 topology and processing; HPA subcellular). Titrate permeabilisation on matched samples because the catalog antibody’s IF epitope and IF conditions are not supplied (caption A02922-2; standard IF practice). The paraffin-section IHC conditions do not establish IF performance (caption A02922-2).
What should I check when AGR2 DAB staining looks diffuse?
First inspect a no-primary section for signal produced by detection reagents, endogenous peroxidase or tissue pigment (standard chromogenic IHC practice). Use a peroxidase block before HRP detection and compare the same DAB development time across sections (standard chromogenic IHC practice). The selected image used 10% goat serum blocking, a peroxidase-conjugated secondary for 30 minutes at 37°C, and DAB development (caption A02922-2). If diffuse staining persists, titrate the primary below the illustrated 2 μg/ml while keeping retrieval and development fixed (caption A02922-2; standard IHC practice). Judge residual signal against expected glandular cytoplasmic staining rather than overall section colour (HPA tissue IHC; standard IHC practice).
How can I compare AGR2 staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the epithelial or glandular compartment before scoring because reported AGR2 tissue staining is cytoplasmic and concentrated in glandular tissues (HPA tissue IHC). Record the percentage of positive target cells and staining intensity; an H-score combines intensity categories from 0–3 with their percentages (standard IHC scoring practice). Normalise positive-cell counts to all eligible target cells, or report positive-cell density per mm² of eligible tissue rather than whole-section area (standard image-analysis practice). Apply identical retrieval, antibody concentration, DAB development and threshold settings across the comparison set (standard IHC practice). Report excluded necrotic or folded areas and inspect representative fields to verify that automated segmentation captured the intended cells (standard IHC practice).
How do I distinguish true AGR2 signal from artefact?
Give greatest weight to cytoplasmic staining in the expected epithelial or glandular cells, consistent with reported tissue and endoplasmic-reticulum localisation (HPA tissue IHC; HPA subcellular). Treat isolated nuclear staining cautiously because the supported subcellular location is the endoplasmic reticulum (HPA subcellular). Inspect section edges, folds and necrotic regions for staining that tracks processing damage rather than cell boundaries (standard IHC practice). A no-primary section helps identify endogenous enzyme or detection signal when HRP and DAB are used (standard chromogenic IHC practice; caption A02922-2). Interpret a plausible pattern alongside controls and morphology because HPA rates agreement between antibody staining and RNA expression as medium (HPA tissue IHC reliability).
Boster reagents
Best AGR2 / Anterior gradient protein 2 homolog IHC Antibodies
Two anti-AGR2 antibodies have paraffin-section IHC images in human tissue (catalog IHC captions); both list IF/ICC applications, and one has an IF image (catalog applications; M02922 IF caption).
Real IHC data
Anti-Anterior Gradient 2/AGR2 Antibody ®
Cat # A02922-2
Real IHC data
Anti-AGR2/Ag 2 Rabbit Monoclonal Antibody
Cat # M02922
A02922-2 has IHC images from human colorectal adenocarcinoma, non-small cell lung cancer, and bladder infiltrating urothelial carcinoma with squamous differentiation (A02922-2 IHC captions). M02922 has an IHC image from paraffin-embedded human uterus and an IF image at 1:50 dilution (M02922 IHC and IF captions).
Which to pick: For tissue IHC, choose A02922-2 for its documented paraffin-section examples or M02922 for its human uterus example; neither caption reports the fixative (A02922-2 and M02922 IHC captions). For IF/ICC, M02922 is the rabbit monoclonal with an IF image, while A02922-2 also lists IF/ICC at 5 μg/ml (M02922 catalog and IF caption; A02922-2 catalog). For cross-species work, A02922-2 lists human, mouse, and rat reactivity, although its supplied IHC images show human tissue only (A02922-2 catalog and IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O95994 (AGR2_HUMAN, Anterior gradient protein 2 homolog).
- Human Protein Atlas. AGR2 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. AGR2 subcellular location (ICC-IF): Localized to the endoplasmic reticulum..
- Human Protein Atlas. AGR2 antibody validation summary (1 antibodies).
- Anterior gradient protein 2 expression in high grade head and neck squamous cell carcinoma correlated with cancer stem cell and epithelial mesenchymal transition. Oncotarget 2015 — PMC4496185.
- Significance of the metastasis-inducing protein AGR2 for outcome in hormonally treated breast cancer patients. British journal of cancer 2006 — PMC2361240.
- The Utility of SOX2 and AGR2 Biomarkers as Early Predictors of Tamoxifen Resistance in ER-Positive Breast Cancer Patients. International journal of surgical oncology 2021 — PMC8460385.
- Serum Level of Tumor-Overexpressed AGR2 Is Significantly Associated with Unfavorable Prognosis of Canine Malignant Mammary Tumors. Animals : an open access journal from MDPI 2021 — PMC8532596.
- PubMed PMID:9790916 — UniProt-cited evidence.
- PubMed PMID:12975309 — UniProt-cited evidence.
- PubMed PMID:12853948 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for AGR2 (Anterior gradient protein 2 homolog). Expected localisation Cytoplasmic staining in glandular tissues (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A02922-2). Validated IHC antibody: A02922-2 at 2-5μg/ml (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 colorectal adenocarcinoma tissue; fixative not specified (datasheet A02922-2); 2. Fixation: Image fixative and duration unreported (datasheet A02922-2); 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 A02922-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A02922-2); 8. Primary antibody: Rabbit anti-AGR2, 2-5μg/ml (datasheet A02922-2); 9. Primary incubation: Overnight at 4 °C (datasheet A02922-2). Watch for: Fixation: Keep fixation consistent across samples (standard IHC practice; not target-specific); Caveat: Secreted AGR2 may stain beyond producer cells (UniProt); Isoform / epitope: No isoforms annotated; mature chain excludes signal peptide (UniProt); Regulation: Enhanced RNA in cervix, intestine, stomach (HPA tissue RNA). Evidence: UniProt O95994, HPA tissue IHC · Enhanced, HPA ICC-IF · endoplasmic reticulum., Datasheet A02922-2, PMC4496185, PMC2361240. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/AGR2/immunohistochemistry-ihc-guide.