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FOXL2 / Forkhead box protein L2 · IHC design guide
Design Immunohistochemistry for FOXL2
Plan chromogenic FOXL2 IHC in paraffin sections using ovarian follicle cell nuclear staining as a reference (HPA tissue IHC). This guide covers fixation consistency, controls, and nuclear scoring (standard IHC practice).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
FOXL2 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 | Nuclear staining in tissue sections (HPA tissue IHC) | |
| Staining pattern | Ovarian follicle nuclei; stromal nuclei in ovary and endometrium (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A01185-1) | |
| Positive control | Endometrium+1 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A01185-1) | |
| Caveat | Stromal nuclei may stain alongside ovarian follicle cells (HPA tissue IHC) | |
| Regulation | Expression persists in adult ovarian follicle cells (UniProt) | |
| Isoform / epitope | No annotated isoforms or processing; one 1–376 chain (UniProt) |
Section 1
Recommended FOXL2 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is followed by four published FOXL2 IHC examples from gonadal and ovarian samples (PMC4217102; PMC11731763; PMC5464638; PMC13328056).
| Sample | Paraffin-embedded mouse ovary tissue; fixative not specified (datasheet A01185-1) |
| Fixation | Image fixative and duration unreported (datasheet A01185-1); 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 A01185-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A01185-1) |
| Primary antibody | Rabbit anti-FOXL2, 2 μg/ml (datasheet A01185-1) |
| Primary incubation | Overnight at 4 °C (datasheet A01185-1) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A01185-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | FOXL2-positive staining in smooth muscle cells of endometrium (HPA tissue IHC: Medium). HPA tissue profile: Nuclear expression in ovarian follicle cells and stromal cells in ovary and endometrium. No signal in the no-primary control. |
💡Decision noteStart with EDTA pH 8.0 heat retrieval for the catalog antibody (datasheet: A01185-1). Published protocols used other retrieval conditions with their own antibodies (PMC11731763; PMC13328056).
Section 2
What Is the Expected FOXL2 Staining Pattern?
FOXL2 should stain nuclei, especially ovarian follicle cells; endometrial smooth muscle cells also show medium staining (UniProt P58012: nucleus; HPA tissue IHC: follicle cells and smooth muscle cells, Medium). HPA describes nuclear expression in ovarian and endometrial stromal cells, without assigning those cells an intensity here (HPA tissue IHC: profile). The tissue IHC assessment is Enhanced, with external characterization supporting the staining pattern (HPA tissue IHC: reliability). FOXL2 has no transmembrane segment (UniProt P58012: topology).
| Discrete nuclear staining in ovarian follicle cells, with little signal outside their nuclei. | This fits FOXL2’s nuclear location and the observed Medium follicle-cell signal (UniProt P58012: subcellular location; HPA tissue IHC: ovary). Judge the pattern in identified follicle cells, since surrounding tissue may contain different cell populations (general IHC interpretation practice). |
| Nuclear staining in endometrial smooth muscle cells; other endometrial cells vary. | Medium staining in smooth muscle cells is an observed positive pattern (HPA tissue IHC: endometrium). HPA also reports nuclear expression in endometrial stromal cells, but this payload gives no separate stromal-cell intensity; avoid assigning one (HPA tissue IHC: profile). |
| Predominantly cytoplasmic or membrane staining, with no convincing nuclear signal. | That compartment disagrees with the expected nuclear pattern (UniProt P58012: subcellular location; HPA tissue IHC: profile). Treat it as suspect until a positive control and detection controls are reviewed; apparent cytoplasmic color alone does not establish FOXL2 expression (general IHC interpretation practice). |
| Strong staining in cells listed as undetected by HPA, such as adipocytes or adrenal glandular cells. | This conflicts with those cell-specific observations (HPA tissue IHC: adipose tissue and adrenal gland, Not detected). Consider cross-reactivity or endogenous detection activity, especially if staining follows tissue pigment, edges, or the control slide (general IHC troubleshooting practice). |
| No nuclear staining in morphologically identifiable ovarian follicle cells. | This misses a supplied positive reference (HPA tissue IHC: ovary, follicle cells, Medium). Check the control tissue, slide morphology, antibody identification, and detection run before calling the specimen negative; a failed run cannot establish biological absence (general IHC practice). |
💡Expected FOXL2 appearanceCall positive when distinct nuclear staining appears in ovarian follicle cells at roughly Medium intensity; isolated diffuse cytoplasmic color or staining confined to HPA-undetected cell types is suspect (HPA tissue IHC: ovary and negative panel; UniProt P58012: nucleus).
| Cell-level reference pattern | Ovarian follicle cells and endometrial smooth muscle cells are both Medium on HPA tissue IHC. Score the identified cell type, not an entire tissue as uniformly positive; HPA’s ovarian and endometrial stromal profile does not supply a separate intensity for each stromal population (HPA tissue IHC: positive entries and profile). |
| Subcellular location and topology | FOXL2 is a nuclear protein with no transmembrane segment (UniProt P58012: subcellular location and topology). A convincing chromogenic result should resolve nuclear signal in the relevant cells; broad membrane-associated staining needs independent scrutiny (general IHC interpretation practice). |
| Antibody evidence | The tissue pattern has Enhanced reliability, supported by external characterization, and antibody HPA069613 has Enhanced IHC validation (HPA tissue IHC: reliability; HPA antibodies: HPA069613). These assessments support the reported pattern; they do not validate a different antibody or every tissue condition. |
| Protein form and modifications | UniProt lists one FOXL2 chain spanning residues 1–376, no signal peptide or propeptide, and a modified residue at serine 33 (UniProt P58012: processing and modified residues). No epitope position is supplied, so these annotations do not justify a target-specific retrieval or fixation prediction. |
| IF/ICC expectation? | HPA reports FOXL2 mainly in the nucleoplasm and rates HPA069613 ICC as Supported (HPA subcellular ICC-IF; HPA antibodies: HPA069613). For an IF/ICC image, assess nuclear localization against a nuclear counterstain (general IF practice); use the separate IF/ICC guide for its workflow. |
| Situation | Likely cause | Next action |
|---|---|---|
| Ovarian follicle cells show no convincing nuclear color. | The supplied positive reference is missed; the cause could lie anywhere in the IHC workflow (HPA tissue IHC: ovary, follicle cells, Medium; general IHC practice). | Check tissue identity and morphology, then review the run’s positive control, antibody identity, retrieval record, and detection reagents (general IHC troubleshooting practice). Do not infer FOXL2 absence from a run whose positive control also failed. |
| Most tissue compartments have a uniform brown haze. | Diffuse background can arise from insufficient blocking, incomplete washing, or detection chemistry rather than cell-restricted target signal (general chromogenic IHC practice). | Compare with a control lacking primary antibody and review blocking, wash, and chromogen-development steps (general IHC practice). Reassess only discrete nuclei in the supplied positive cell types (HPA tissue IHC: ovary and endometrium). |
| Color is strongest in cytoplasm or at cell borders. | That distribution conflicts with nuclear FOXL2 and HPA’s nuclear tissue profile (UniProt P58012: subcellular location; HPA tissue IHC: profile). | Inspect a known-positive section for resolvable nuclear staining and compare the same run’s detection controls (general IHC practice). Record cytoplasmic or border color separately instead of scoring it as confirmed FOXL2. |
| Adipocytes or adrenal glandular cells stain strongly. | HPA reports FOXL2 as Not detected in those respective cells; off-target binding or endogenous detection activity is possible (HPA tissue IHC: negative entries; general IHC practice). | Verify the stained cell type and compare a control lacking primary antibody (general IHC practice). If the unexpected pattern persists, treat it as unconfirmed and review antibody specificity; HPA’s negative observation is a reference, not proof that every specimen must be blank. |
| Endometrium appears positive, but the stained cells are unclear. | HPA specifies Medium signal in smooth muscle cells and separately describes nuclear stromal expression; the two statements do not assign every endometrial cell the same score (HPA tissue IHC: positive entry and profile). | Use morphology and a nuclear counterstain to identify the stained compartment and cell population (general IHC practice). Report the observed cell type and nuclear pattern rather than labeling the whole endometrium positive. |
| An IF/ICC image appears broadly fluorescent instead of nucleoplasmic. | The expected ICC-IF location is mainly nucleoplasmic; broad fluorescence may reflect background or an unresolved cell boundary (HPA subcellular ICC-IF; general IF practice). | Compare fluorescence with the nuclear counterstain and appropriate staining controls (general IF practice). Interpret this as an IF/ICC localization check; it does not establish an IHC-P dilution or retrieval condition. |
Experiment evidence
IHC & IF images showing FOXL2 staining
A01185-1 · IHCIHC analysis of FOXL2 using anti-FOXL2 antibody (A01185-1). FOXL2 was detected in a paraffin-embedded section of mouse ovary tissue. Heat me
A01185-1 · IHCIHC analysis of FOXL2 using anti-FOXL2 antibody (A01185-1). FOXL2 was detected in a paraffin-embedded section of rat ovary tissue. Heat medi
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000183770-FOXL2/tissue/cerebral+cortex#imid_19299363
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000183770-FOXL2/tissue/colon#imid_19299289
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000183770-FOXL2/tissue/liver#imid_19299298
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000183770-FOXL2/tissue/kidney#imid_19299307
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA069613; green = FOXL2, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA069613; green = FOXL2, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for FOXL2 IHC & IF
🧪Run ovary first and look for nuclear staining in follicle cells (HPA: Medium in ovary follicle cells; UniProt P58012: nucleus). Use adipose tissue as the negative tissue and assess its adipocytes for absent staining (HPA: Not detected in adipocytes); on the ovary slide, treat other cells as internal negative comparators only when they lack specific nuclear signal.
Positive control tissue: Endometrium (Smooth muscle cells, HPA Medium)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show FOXL2 in A-431, K-562, SiHa, with annotated localisation: Nucleoplasm (supported) (HPA subcellular).
Technical controls: Include a no-primary (secondary-only) control, a host- and class-matched nonimmune rabbit IgG isotype control, and FOXL2 knockout material as a biological negative where available (selected-SKU caption: rabbit primary antibody; standard IHC practice). Quench endogenous peroxidase and check for nonspecific DAB signal in the ovary section (selected-SKU caption: HRP/DAB detection; standard chromogenic IHC practice).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported in the supplied evidence, and the selected-SKU paraffin-section caption does not state a fixative (selected-SKU caption: fixative unreported). The caption uses heat retrieval in EDTA at pH 8.0, but it does not establish that retrieval is required or that frozen sections or IF are easier (selected-SKU caption: EDTA heat retrieval; HPA: nucleoplasmic ICC-IF localisation). Watch for endogenous peroxidase background when interpreting ovary DAB staining (selected-SKU caption: HRP/DAB detection; standard chromogenic IHC practice).
HPA tissue IHC evidence for FOXL2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — External characterization data supports antibody staining.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Endometrium | Smooth muscle cells | Medium | Protein (IHC) | HPA → |
| Ovary | Follicle cells | Medium | 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 → |
| Appendix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced FOXL2 IHC Tips
Troubleshoot FOXL2 staining in paraffin-section chromogenic IHC using the catalog antibody’s tissue caption, protein annotations, and tissue-expression evidence.
Which antigen retrieval should I try first for weak FOXL2 staining?
Start with heat-mediated antigen retrieval in EDTA at pH 8.0 for paraffin sections (datasheet A01185-1). The selected mouse ovary image used that retrieval, followed by 10% goat serum blocking and 2 μg/ml primary antibody overnight at 4°C (caption A01185-1). Run a known positive ovary section alongside the test section and compare nuclear signal in follicle cells (HPA tissue IHC; standard IHC practice). If staining remains weak, adjust heating duration in a controlled series while keeping antibody concentration and detection constant (standard IHC practice). Record tissue preservation and background as well as signal, because excessive heating can damage section morphology (standard IHC practice).
Could fixation explain variable FOXL2 staining between paraffin blocks?
The selected paraffin-section caption does not state a fixative, so FOXL2 sensitivity to any particular fixation condition is unknown for this antibody (caption A01185-1). Record each block’s fixative, fixation duration, and processing history before comparing staining intensity across specimens (standard IHC practice). Stain matched sections together using EDTA at pH 8.0 and the same detection settings to limit technical variation (datasheet A01185-1; standard IHC practice). Use an ovary section with assessable follicle cells as a positive reference, and inspect morphology before calling a faint nucleus negative (HPA tissue IHC; standard IHC practice). Treat any fixation effect observed in this comparison as an experimental finding, not an established FOXL2-specific property (caption A01185-1).
Where should credible FOXL2 staining appear in tissue sections?
Prioritize staining that overlaps the nuclear counterstain: FOXL2 is annotated as nuclear, with supported nucleoplasmic localization (UniProt P58012; HPA subcellular). In ovary, assess follicle-cell nuclei and the reported stromal-cell nuclear pattern; HPA rates follicle-cell staining as medium (HPA tissue IHC). HPA also reports nuclear expression in endometrium and medium staining in its smooth muscle cells, so identify the compartment before comparing tissues (HPA tissue IHC). Diffuse cytoplasmic DAB without corresponding nuclear staining warrants review of background and morphology rather than an immediate positive call (UniProt P58012; standard IHC practice). Compare the pattern with a no-primary control on a nearby section when localization is ambiguous (standard IHC practice).
Can isoforms or epitope changes explain discordant FOXL2 staining?
The supplied record lists one FOXL2 chain spanning residues 1–376 and no annotated isoforms; it does not map this antibody’s epitope (UniProt P58012; caption A01185-1). FOXL2 has no annotated transmembrane segment or signal peptide, consistent with evaluating an intracellular nuclear pattern in sections (UniProt P58012). Phosphoserine at position 33 is annotated, but that annotation does not establish whether this antibody recognizes or depends on that modification (UniProt P58012). If sections disagree, compare retrieval and staining runs before attributing the difference to an isoform or modified epitope (standard IHC practice). Resolve persistent disagreement with an independently characterized FOXL2 antibody or an appropriate specificity control, where available (standard IHC practice).
How should I assess FOXL2 in a multiplex fluorescence experiment?
For fluorescence work related to this IHC assessment, pair nuclear FOXL2 signal with a separately validated marker identifying the expected follicle cells (HPA tissue IHC; standard IF practice). Choose a spectrally separated fluorophore, favoring a longer-wavelength channel if the tissue autofluoresces in shorter-wavelength channels, and inspect single-stain controls (standard IF practice). Because FOXL2 is nuclear and has no transmembrane segment, permeabilisation must allow antibody access to the nuclear compartment; the antibody’s precise epitope is unreported (UniProt P58012; standard IF practice). Include a nuclear counterstain and check colocalization rather than judging brightness alone (HPA subcellular; standard IF practice). The selected antibody caption documents chromogenic paraffin-section IHC, so it does not establish an IF dilution or fixation condition (caption A01185-1).
How can I reduce diffuse or misleading brown FOXL2 signal?
Begin with a no-primary section and inspect whether brown deposits persist outside nuclei, particularly where tissue is damaged or section edges stain strongly (standard IHC practice). The selected ovary section used 10% goat serum blocking, 2 μg/ml primary overnight at 4°C, and a peroxidase-conjugated secondary for 30 minutes at 37°C (caption A01185-1). Apply a peroxidase block before HRP detection and control DAB development consistently across compared sections (standard IHC practice). If background remains, adjust antibody exposure or blocking while retaining a positive ovary control in the same run (HPA tissue IHC; standard IHC practice). Accept staining as FOXL2-like only when interpretable nuclei retain signal above controls (UniProt P58012; standard IHC practice).
How should I score FOXL2 IHC across samples? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and tissue region before scoring; in ovary, follicle cells provide a documented FOXL2-positive population (HPA tissue IHC; standard IHC practice). Report the percentage of eligible cells with nuclear DAB and, when intensity matters, an H-score from 0–300 using intensity grades 0–3 (standard IHC practice). Normalize each result to the number of assessable nuclei in that same cell population, excluding damaged regions by a preset rule (standard IHC practice). Keep retrieval, antibody exposure, imaging, and scoring thresholds consistent across a comparison set (standard IHC practice). Record stromal and follicle-cell results separately so changes in their proportions do not masquerade as changes in nuclear FOXL2 staining (HPA tissue IHC; standard IHC practice).
What distinguishes genuine FOXL2 staining from an IHC artefact?
A persuasive positive pattern places DAB in intact nuclei of expected cells, including ovarian follicle cells, and exceeds the no-primary control (UniProt P58012; HPA tissue IHC; standard IHC practice). HPA also reports stromal nuclear expression, so identify the stained cell population before judging whether a signal is unexpected (HPA tissue IHC). Cytoplasmic-only staining conflicts with the supported nuclear and nucleoplasmic localization and should prompt a background check (UniProt P58012; HPA subcellular; standard IHC practice). Treat edge staining, necrotic regions, and deposits attributable to endogenous peroxidase as potential artefacts during chromogenic scoring (standard IHC practice). A negative result in an expected population requires an interpretable positive control before it supports a biological conclusion (HPA tissue IHC; standard IHC practice).
Boster reagents
Best FOXL2 / Forkhead box protein L2 IHC Antibodies
A01185-1 has real IHC data from paraffin sections of mouse and rat ovary and human lung and ovarian cancer tissue (catalog IHC captions); IF data are absent (catalog IF images).
Real IHC data
Anti-FOXL2 Antibody ®
Cat # A01185-1
A01185-1 is listed for IHC in human, mouse, and rat samples (catalog applications and reactivity). Its IHC captions show paraffin sections of mouse and rat ovary and human lung and ovarian cancer tissue (catalog IHC captions).
Which to pick: Choose A01185-1 for paraffin-section IHC across human, mouse, and rat samples: it is a rabbit antibody listed for IHC in all three species, with examples in its own IHC captions (catalog host, applications, reactivity, and IHC captions). Its captions do not report the fixative (catalog IHC captions). For IF/ICC, A01185-1 has no listed IF/ICC application or IF image, so IF/ICC performance is unverified (catalog applications and IF images).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P58012 (FOXL2_HUMAN, Forkhead box protein L2).
- Human Protein Atlas. FOXL2 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. FOXL2 subcellular location (ICC-IF): Mainly localized to the nucleoplasm..
- Human Protein Atlas. FOXL2 antibody validation summary (1 antibodies).
- Molecular cloning and analysis of gonadal expression of Foxl2 in the rice-field eel Monopterus albus. Scientific reports 2014 — PMC4217102.
- Protective effect of luteinizing hormone on frozen-thawed ovarian follicles and granulosa cells. PloS one 2025 — PMC11731763.
- Clinical and genetic analysis of recurrent adult-type granulosa cell tumor of the ovary: Persistent preservation of heterozygous c.402C>G FOXL2 mutation. PloS one 2017 — PMC5464638.
- Investigating autoimmunity in the etiology of premature ovarian insufficiency in a mouse model. Journal of reproductive immunology 2026 — PMC13328056.
- PubMed PMID:11175783 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
- PubMed PMID:16153597 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for FOXL2 (Forkhead box protein L2). Expected localisation Nuclear staining in tissue sections (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A01185-1). Validated IHC antibody: A01185-1 at 2 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Endometrium (Smooth muscle cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded mouse ovary tissue; fixative not specified (datasheet A01185-1); 2. Fixation: Image fixative and duration unreported (datasheet A01185-1); 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 A01185-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A01185-1); 8. Primary antibody: Rabbit anti-FOXL2, 2 μg/ml (datasheet A01185-1); 9. Primary incubation: Overnight at 4 °C (datasheet A01185-1). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A01185-1); Caveat: Stromal nuclei may stain alongside ovarian follicle cells (HPA tissue IHC); Isoform / epitope: No annotated isoforms or processing; one 1–376 chain (UniProt); Regulation: Expression persists in adult ovarian follicle cells (UniProt). Evidence: UniProt P58012, HPA tissue IHC · Enhanced, HPA ICC-IF · Mainly localized to the nucleoplasm., Datasheet A01185-1, PMC4217102, PMC11731763. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/FOXL2/immunohistochemistry-ihc-guide.