STC2 / Stanniocalcin-2 · IHC design guide

Design Immunohistochemistry for STC2

Plan paraffin-section STC2 IHC around cytoplasmic or membranous staining in most tissues (HPA tissue IHC). Compare high staining in breast glandular cells with undetected staining in adipocytes (HPA tissue IHC), and account for secretion when interpreting the signal (UniProt).

Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use

Immunohistochemistry protocol sheet for STC2 (IHC for STC2): expected localisation Cytoplasmic or membranous tissue staining (HPA tissue IHC), antibody A05017, validated IHC image, and IHC protocol steps — Printable **STC2** IHC protocol sheet — expected localisation Cytoplasmic or membranous tissue staining (HPA tissue IHC), antibody A05017, controls and protocol steps. Open the full STC2 IHC guide →

Navigate to: Protocols Staining pattern Controls Antibodies

STC2 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 or membranous tissue staining (HPA tissue IHC)
	Staining pattern	Cytoplasmic or membranous signal in most tissues (HPA tissue IHC)
	Antigen retrieval	EDTA pH 8.0 HIER, heat-mediated (datasheet A05017)
	Positive control ⓘ	Adrenal gland+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 conditions consistent across sections. (standard IHC practice; not target-specific)
	Caveat	Secreted STC2 may stain beyond producing cells (UniProt)
	Regulation	Expression regulation is not established (UniProt)
	Isoform / epitope	No annotated isoforms; signal peptide 1–24 is removed (UniProt)

Section 1

Recommended STC2 IHC & IF Protocols

Compare the catalog antibody’s IHC-P protocol (datasheet: A05017) with four published STC2 IHC protocols (PMC8794563; PMC4186577; PMC12170999; PMC11245224).

Recommended immunohistochemistry (IHC-P) protocol parameters
Sample	Paraffin-embedded human breast cancer tissue; fixative not specified (datasheet A05017)
Fixation	Image fixative and duration unreported (datasheet A05017); 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 A05017); 20 min, 95–100 °C (standard)
Peroxidase block	3% H2O2, 10 min, room temperature (standard)
Blocking	10% goat serum (datasheet A05017)
Primary antibody	Rabbit anti-STC2, 2-5 μg/ml (datasheet A05017)
Primary incubation	Overnight at 4 °C (datasheet A05017)
Detection	HRP-conjugated secondary, DAB chromogen (datasheet A05017)
Counterstain	Hematoxylin, blue, dehydrate and mount (standard)
Expected result	STC2-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic or membranous expression in most tissues. No signal in the no-primary control.

💡Decision noteStart with heat-mediated EDTA at pH 8.0 for the catalog antibody (datasheet: A05017); the colorectal studies used citrate-based retrieval (PMC8794563; PMC12170999).

Section 2

What Is the Expected STC2 Staining Pattern?

STC2 is secreted and has no transmembrane segment (UniProt O76061 topology). In tissue IHC, expect cytoplasmic or membranous staining in most tissues, with high staining in selected glandular, glial, glomerular, immune and macrophage populations (HPA tissue IHC). The tissue profile is Approved, but HPA notes that secreted proteins can show complex RNA–protein relationships and that external verification is pending (HPA tissue IHC reliability).

What am I looking at on my slide?
Cytoplasmic or membranous staining appears in breast glandular cells or lung macrophages.	This matches the reported compartment and high-staining cell populations (HPA tissue IHC: breast glandular cells High; lung macrophages High). Judge the named cells separately from neighboring cells; secretion can complicate attribution of nearby signal (UniProt O76061: Secreted; HPA tissue IHC reliability).
The dominant signal is sharply nuclear, with little cytoplasmic or membranous staining.	A nuclear-only pattern does not match the reported tissue profile or approved ER location in ICC-IF (HPA tissue IHC profile; HPA subcellular). Check morphology, counterstain and detection controls before assigning that signal to STC2 (general IHC practice).
Strong staining appears in adipocytes or cardiomyocytes, while expected positive cells are weak.	Those cell types were reported as Not detected (HPA tissue IHC: adipocytes; cardiomyocytes). Consider cross-reactivity or endogenous detection activity, then compare with reagent controls and a known-positive section (general IHC practice).
Broad, hazy color covers tissue and background, obscuring cell boundaries.	This is difficult to score against HPA's cell-resolved cytoplasmic or membranous profile (HPA tissue IHC profile). Review blocking, washes, chromogen development and the detection-only control for nonspecific background (general IHC practice).
No staining is visible in an expected high-staining population.	Check that the relevant cells are present: breast glandular cells, lung macrophages and kidney glomerular cells are reported High (HPA tissue IHC). If present, review antibody dilution, retrieval and detection performance with a positive control (general IHC practice).

💡Expected STC2 appearanceCall a result positive when identifiable HPA-high cells show clear cytoplasmic or membranous chromogen above local background; isolated nuclear staining or strong signal confined to HPA Not detected cell types warrants investigation (HPA tissue IHC profile and levels; HPA subcellular).

How each factor affects the staining
Tissue and cell selection	Use a reported High population, such as breast glandular cells, lung macrophages or kidney glomerular cells, to assess sensitivity (HPA tissue IHC). Adipocytes and cardiomyocytes offer reported Not detected comparisons (HPA tissue IHC); interpret each cell type within its own tissue context.
Secreted-protein interpretation	STC2 has a signal peptide at residues 1–24, a mature chain at 25–302 and no transmembrane segment (UniProt O76061 topology/processing). HPA cautions that RNA location and protein staining may differ for secreted variants (HPA tissue IHC reliability).
Evidence strength	The tissue profile and the listed antibody's IHC status are Approved (HPA tissue IHC reliability; HPA antibody HPA045372). HPA also flags pending external verification (HPA tissue IHC reliability); the supplied record does not establish an Enhanced IHC result (HPA antibody HPA045372).
IF/ICC Q&A	Where should STC2 appear in IF/ICC? HPA reports an approved endoplasmic reticulum location and ICC approval for HPA045372 (HPA subcellular; HPA antibody HPA045372). This cell-image finding helps interpret localization; tissue IHC has its own cytoplasmic or membranous profile (HPA tissue IHC profile).

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
A breast section appears negative.	The assessed area may lack the relevant glandular cells, or the staining run may have failed (HPA tissue IHC: breast glandular cells High; general IHC practice).	Confirm glandular cells on the counterstained section, then inspect a known-positive control and the staining run before interpreting absence in the specimen (general IHC practice).
A heart muscle section stains strongly throughout cardiomyocytes.	HPA reports cardiomyocytes as Not detected, despite UniProt listing expression in heart among various tissues (HPA tissue IHC: heart muscle; UniProt O76061 tissue specificity).	Verify cell identity and compare reagent controls; do not equate tissue-level expression with cardiomyocyte protein staining (general IHC practice; HPA tissue IHC: cardiomyocytes Not detected).
Nuclei dominate the signal.	The compartment conflicts with HPA's cytoplasmic or membranous tissue pattern and approved ER location in ICC-IF (HPA tissue IHC profile; HPA subcellular).	Check counterstain overlap and detection-only controls; reassess localization in a reported High cell population (general IHC practice; HPA tissue IHC levels).
Background masks macrophages in lung.	Heavy background prevents assessment of a reported High cell population (HPA tissue IHC: lung macrophages High).	Review blocking, washing and chromogen development; compare a detection-only control, then score only identifiable macrophages above local background (general IHC practice).
Signal differs between neighboring cell types.	HPA reports cell-specific levels: kidney glomerular cells are High, while adipocytes are Not detected in adipose tissue (HPA tissue IHC). STC2 secretion can also complicate protein attribution (UniProt O76061: Secreted; HPA reliability).	Score identified cell populations separately, using morphology and an appropriate negative comparison; investigate signal that obscures cell boundaries (general IHC practice).
Positive control stains weakly after a protocol change.	Target-specific fixation effects are not established by the supplied assay evidence. Verify with a matched IHC source before attributing a result to fixation.	Check reagent preparation, dilution, retrieval settings and detection controls against the last working run before drawing a biological conclusion (general IHC practice).

Source: UniProt O76061 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing STC2 staining

IHC analysis of Stanniocalcin 2/STC2 using anti-Stanniocalcin 2/STC2 antibody (A05017). Stanniocalcin 2/STC2 was detected in a paraffin-embedded section of human breast cancer tissue. Heat mediated antigen retrieval was performed in EDTA buffer (pH 8.0, epitope retrieval solution). The tissue section was blocked with 10% goat serum. The tissue section was then incubated with 2 μg/ml rabbit anti-Stanniocalcin 2/STC2 Antibody (A05017) overnight at 4°C. Peroxidase Conjugated Goat Anti-rabbit IgG was used as secondary antibody and incubated for 30 minutes at 37°C. The tissue section was developed using HRP Conjugated Rabbit IgG Super Vision Assay Kit (Catalog # SV0002) with DAB as the chromogen.

A05017 · IHCIHC analysis of Stanniocalcin 2/STC2 using anti-Stanniocalcin 2/STC2 antibody (A05017). Stanniocalcin 2/STC2 was detected in a paraffin-embe

IF analysis of Stanniocalcin 2/STC2 using anti-Stanniocalcin 2/STC2 antibody (A05017). Stanniocalcin 2/STC2 was detected in an immunocytochemical section of PC-3 cells. Enzyme antigen retrieval was performed using IHC enzyme antigen retrieval reagent (AR0022) for 15 mins. The cells were blocked with 10% goat serum. And then incubated with 5 μg/mL rabbit anti-Stanniocalcin 2/STC2 Antibody (A05017) overnight at 4°C. Cy3 Conjugated Goat Anti-Rabbit IgG (BA1032) was used as secondary antibody at 1:500 dilution and incubated for 30 minutes at 37°C. The section was counterstained with DAPI. Visualize using a fluorescence microscope and filter sets appropriate for the label used.

A05017 · IFIF analysis of Stanniocalcin 2/STC2 using anti-Stanniocalcin 2/STC2 antibody (A05017). Stanniocalcin 2/STC2 was detected in an immunocytoche

HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000113739-STC2/tissue/cerebral+cortex#imid_20694304

HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000113739-STC2/tissue/colon#imid_20693278

HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000113739-STC2/tissue/liver#imid_20693295

HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000113739-STC2/tissue/kidney#imid_20693288

HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA045372; green = STC2, blue = nucleus, red = microtubules.

← swipe / scroll for more images →

Real IHC / IF data behind the staining-pattern expectations in this section.

Sample controls for STC2 IHC & IF

🧪Run breast first and score its glandular cells, which show High STC2 staining (HPA: breast glandular cells, High). Use adipose tissue as a negative comparator and score adipocytes, where STC2 is not detected (HPA: adipocytes, Not detected); on the breast slide, assess adjacent nonglandular cells for background staining without assuming they are validated STC2-negative cells.

Positive control tissue: Adrenal 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 STC2 in A-431, U-251MG, U2OS, with annotated localisation: Endoplasmic reticulum (approved) (HPA subcellular).

Technical controls: Include a no-primary, secondary-only control and a concentration-matched rabbit IgG isotype control suited to the rabbit primary antibody (A05017 tissue-IHC caption: rabbit primary). Confirm specificity with STC2 knockout material or a cognate peptide block if available; quench endogenous peroxidase and check background in the breast section before interpreting DAB staining (A05017 tissue-IHC caption: breast section and HRP/DAB detection).

⚠️Feasibility: The exact A05017 paraffin-section caption does not report a fixative, and the supplied evidence reports no STC2-specific fixation window or fixation effect (A05017 tissue-IHC caption). Its demonstrated IHC condition uses heat retrieval in EDTA, pH 8.0; this does not establish that retrieval is required under every condition (A05017 tissue-IHC caption). The evidence does not establish whether frozen sections or IF are easier; in breast glandular tissue, interpret possible luminal or extracellular staining cautiously because STC2 is secreted (HPA: breast glandular cells, High; UniProt O76061: Secreted).

HPA tissue IHC evidence for STC2

Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — At least one protein variant secreted, tissue location of RNA and protein might differ and correlation is complex. Pending external verification.). 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
Adrenal gland	Glandular cells	High	Protein (IHC)	HPA →
Breast	Glandular cells	High	Protein (IHC)	HPA →
Caudate	Glial cells	High	Protein (IHC)	HPA →
Cerebral cortex	Glial cells	High	Protein (IHC)	HPA →
Gallbladder	Glandular cells	High	Protein (IHC)	HPA →

Undetected expression · recommended negative controls

Tissue	Cell type	Level	Evidence	Source
Adipose tissue	Adipocytes	Not detected	Protein (IHC)	HPA →
Heart muscle	Cardiomyocytes	Not detected	Protein (IHC)	HPA →
Parathyroid gland	Glandular cells	Not detected	Protein (IHC)	HPA →
Skeletal muscle	Myocytes	Not detected	Protein (IHC)	HPA →
Soft tissue	Fibroblasts	Not detected	Protein (IHC)	HPA →

Section 3

Advanced STC2 IHC Tips

Use the catalog antibody’s paraffin-section protocol as the IHC starting point, then assess staining against STC2’s secreted biology and reported tissue distribution.

Which antigen retrieval conditions should I try first for STC2 paraffin sections?

Start with heat-mediated retrieval in EDTA at pH 8.0 (datasheet A05017). The catalog antibody stained a paraffin-embedded human breast cancer section after this retrieval, followed by 2 μg/ml primary antibody overnight at 4°C (caption A05017). Keep section thickness, heating duration and cooling procedure consistent across comparison slides so retrieval changes can be judged fairly (standard IHC practice). If staining is weak, adjust heating duration on adjacent sections before testing another retrieval buffer, and compare tissue preservation alongside signal (standard IHC practice). Include a no-primary control to distinguish retrieval-related background from antibody-dependent staining (standard IHC practice).

How should I troubleshoot weak STC2 staining when fixation history is uncertain?

STC2-specific fixation sensitivity is unknown because the selected tissue-IHC caption identifies a paraffin section but does not report its fixative (caption A05017). Record the fixative and fixation duration for each specimen, then compare sections with matched processing histories before changing antibody concentration (standard IHC practice). The documented starting conditions are EDTA pH 8.0 retrieval and 2 μg/ml primary antibody overnight at 4°C (caption A05017). If only some blocks stain poorly, check whether morphology and other established tissue markers show a similar processing effect (standard IHC practice). Do not assign weak staining to a particular fixative without a controlled comparison (standard IHC practice).

Where should convincing STC2 staining appear in a tissue section?

Expect predominantly cytoplasmic or membranous tissue staining, while allowing for extracellular signal from a secreted protein (HPA tissue IHC profile; UniProt O76061 subcellular location). An endoplasmic-reticulum pattern has been approved in cell imaging, but tissue IHC cannot by itself establish that organelle as the source of diffuse cytoplasmic color (HPA subcellular; standard IHC interpretation). STC2 has a signal peptide at residues 1–24 and no transmembrane segment, so a sharp cell-surface rim alone deserves scrutiny (UniProt O76061 processing and topology). Compare the cellular pattern with glandular cells in breast or adrenal gland and glial cells in cerebral cortex, which have high reported staining (HPA tissue IHC).

Could epitope choice explain discordant STC2 staining patterns?

Ask for the antibody’s immunogen or mapped epitope before attributing a discordant pattern to sequence coverage (standard IHC practice). The record lists 0 annotated isoforms, a cleaved signal peptide at residues 1–24, and a mature chain spanning 25–302 (UniProt O76061 isoforms and processing). A reagent directed only against the signal peptide could behave differently from one recognizing the mature protein, but the selected caption does not identify its epitope (UniProt O76061 processing; caption A05017). Glycosylation at residue 73 and phosphorylation at 250, 251 and 254 are documented; their effect on this antibody’s staining is unknown (UniProt O76061 modifications).

How can I use IF to investigate an ambiguous STC2 IHC pattern?

Use IF as a separate follow-up assay: the supplied A05017 caption documents chromogenic paraffin-section IHC, not IF validation (caption A05017). Multiplex STC2 with a validated marker for the cell population being examined, such as a glandular-cell or macrophage marker where that population is relevant (HPA tissue IHC; standard IF practice). Select fluorophores after measuring tissue autofluorescence, favoring channels with clear separation from that background (standard IF practice). For an intracellular or endoplasmic-reticulum epitope, include controlled permeabilisation; for an extracellularly accessible epitope, test whether permeabilisation is needed, since this antibody’s epitope is unspecified (HPA subcellular; UniProt O76061 secretion; standard IF practice). Include single-label and no-primary controls when interpreting overlap (standard IF practice).

How do I reduce diffuse brown staining without losing STC2 signal?

First separate tissue pigment and endogenous peroxidase activity from antibody-dependent DAB signal using a no-primary control and an appropriate peroxidase block (standard chromogenic IHC practice). The documented workflow used 10% goat serum, 2 μg/ml rabbit primary overnight at 4°C, a peroxidase-conjugated secondary for 30 minutes at 37°C, and DAB (caption A05017). If the no-primary slide is clean, titrate primary concentration or incubation while keeping EDTA pH 8.0 retrieval constant (datasheet A05017; standard IHC practice). Check whether excess color follows section edges, folds or damaged regions rather than intact cells (standard IHC practice).

What should I score when comparing STC2 across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION

Define the cell population and compartment before scoring because STC2 is secreted and tissue staining is reported as cytoplasmic or membranous (UniProt O76061 subcellular location; HPA tissue IHC profile). For cellular staining, report the percentage of positive target cells and an H-score using intensity categories 0–3, with the same thresholds across slides (standard IHC scoring practice). For a dispersed positive population, report positive cells per mm² of viable tissue and identify the counted cell type (standard IHC quantification practice). Normalize counts to viable tissue area or the number of evaluable target cells, and exclude folds, necrosis and edges consistently (standard IHC practice).

How can I distinguish genuine STC2 positivity from staining artefact?

Treat staining as more persuasive when it appears in intact cells with the reported cytoplasmic or membranous pattern and a clean no-primary control (HPA tissue IHC profile; standard IHC practice). Breast glandular cells and lung macrophages are reported high, whereas adipocytes and cardiomyocytes are reported not detected; use these as contextual comparisons, not absolute controls (HPA tissue IHC). Scrutinize strong nuclear-only staining or a continuous cell-surface rim, given STC2 secretion and absence of a transmembrane segment (UniProt O76061 subcellular location and topology). Exclude edge staining and necrotic regions, and investigate residual endogenous peroxidase signal before assigning DAB color to STC2 (standard chromogenic IHC practice).

Boster reagents

Best STC2 / Stanniocalcin-2 IHC Antibodies

A05017 has IHC data from paraffin-embedded human breast and lung squamous cell carcinomas, plus IF data from PC-3 cells and human cancer sections (A05017 image captions).

Real IHC data

Anti-Stanniocalcin 2/STC2 Antibody ®

Cat # A05017

View product →

A05017 will render with its own IHC figure from a paraffin-embedded human breast cancer section (A05017 IHC image caption). Its IF captions document PC-3 cells and paraffin-embedded human breast and lung cancer sections (A05017 IF image captions).

Which to pick: For tissue IHC, choose A05017: its IHC captions document paraffin-embedded human breast cancer and lung squamous cell carcinoma with EDTA pH 8.0 retrieval; the fixative is unreported (A05017 IHC image captions). For IF/ICC, A05017 has IF data from PC-3 cells and human cancer sections (A05017 IF image captions). For mouse or rat work, A05017 lists both species as reactive, but the supplied IHC and IF images show human samples; clonality is unreported (catalog reactivity; A05017 image captions; catalog clone field).

Each figure is that product's own IHC / IF validation image from its datasheet.

References

UniProt Consortium. UniProt entry O76061 (STC2_HUMAN, Stanniocalcin-2).
Human Protein Atlas. STC2 tissue IHC expression (reliability: Approved).
Human Protein Atlas. STC2 subcellular location (ICC-IF): Localized to the endoplasmic reticulum..
Human Protein Atlas. STC2 antibody validation summary (1 antibodies).
Immunohistochemical Expression of Stanniocalcin 2 in Colorectal Cancer: A Retrospective Egyptian Study. Iranian journal of pathology 2022 — PMC8794563.
Stanniocalcin 2 expression predicts poor prognosis of hepatocellular carcinoma. Oncology letters 2014 — PMC4186577.
Stanniocalcin-2 significantly promotes colorectal cancer progression by regulating cancer cell proliferation and invasion. Journal of Cancer 2025 — PMC12170999.
Stanniocalcin-2 expression in glioblastoma - A novel prognostic biomarker: An observational study. Medicine 2024 — PMC11245224.
PubMed PMID:9723890 — UniProt-cited evidence.
PubMed PMID:9753616 — UniProt-cited evidence.
PubMed PMID:10022771 — UniProt-cited evidence.