BCL9L / B-cell CLL/lymphoma 9-like protein · IHC design guide

Design Immunohistochemistry for BCL9L

Plan BCL9L paraffin-section IHC around its nuclear location (UniProt) and the nuclear and cytoplasmic tissue profile (HPA tissue IHC). This guide covers fixation consistency, staining interpretation, and the uncertain agreement between tissue staining and RNA expression (HPA tissue IHC).

Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
Immunohistochemistry protocol sheet for BCL9L (IHC for BCL9L): expected localisation Nuclear and cytoplasmic tissue staining (HPA tissue IHC); nuclear location (UniProt), antibody A05905-1, validated IHC image, and IHC protocol steps
Printable BCL9L IHC protocol sheet — expected localisation Nuclear and cytoplasmic tissue staining (HPA tissue IHC); nuclear location (UniProt), antibody A05905-1, controls and protocol steps. Open the full BCL9L IHC guide →

BCL9L 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 and cytoplasmic tissue staining (HPA tissue IHC); nuclear location (UniProt)
Staining pattern High squamous epithelial staining; nuclear/cytoplasmic profile (HPA tissue IHC)
Antigen retrieval Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen)
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 consistent across paraffin sections. (standard IHC practice; not target-specific)
Caveat Low consistency between staining and RNA expression (HPA tissue IHC)
Regulation No expression regulator specified (UniProt)
Isoform / epitope 4 isoforms; antibody epitope coverage is unreported (UniProt; datasheets)
Section 1

Recommended BCL9L IHC & IF Protocols

The catalog antibody’s IHC-P protocol is accompanied by three published BCL9L IHC methods (PMC7575756; PMC9141496; PMC5342010).

Recommended immunohistochemistry (IHC-P) protocol parameters
SampleTissue sections; selected-image fixative not specified (standard IHC workflow)
FixationImage fixative and duration unreported (datasheet A05905-1); verify before use.
Sectioning4–5 µm sections on charged slides (standard)
DeparaffinisationXylene, graded ethanol series to water (standard)
Antigen retrievalHeat-induced epitope retrieval in Tris-EDTA buffer, pH 9.0, 20 min at 95–98 °C (standard rule: nuclear antigen)
Peroxidase block3% H2O2, 10 min, room temperature (standard)
Blocking10% normal serum of the secondary host, 30 min, room temperature (standard)
Primary antibodyRabbit anti-BCL9L, 5 μg/mL (datasheet A05905-1)
Primary incubationOvernight at 4 °C (standard)
DetectionHRP-polymer secondary, DAB chromogen 5–10 min (standard)
CounterstainHematoxylin, blue, dehydrate and mount (standard)
Expected resultBCL9L-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Nuclear and cytoplasmic expression in several tissues. 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 rule); the bladder cancer method used 98 °C for 20 min (PMC9141496).
Section 2

What Is the Expected BCL9L Staining Pattern?

BCL9L is a nuclear transcriptional regulator with no transmembrane segment (UniProt Q86UU0). In paraffin-section IHC, look for staining in adrenal glandular cells, kidney tubule cells, and squamous epithelium, where HPA reports high staining (HPA: tissue IHC). HPA also reports nuclear and cytoplasmic staining across several tissues, but rates its tissue IHC profile uncertain because antibody staining and RNA expression have low consistency (HPA: tissue IHC).

What am I looking at on my slide?
Nuclear staining in adrenal glandular cells or kidney tubule cells, with identifiable tissue architecture.This fits BCL9L's nuclear location (UniProt Q86UU0; HPA: nucleoplasm supported) and the cell populations scored high by tissue IHC (HPA: adrenal gland and kidney). Cytoplasmic staining can accompany it because HPA reports both compartments in tissue; record each compartment separately (HPA: tissue IHC, uncertain).
Strong membrane-edge or extracellular staining dominates, with little staining in cell interiors.A membrane-dominant pattern lacks support from the nuclear annotation and absence of a transmembrane segment (UniProt Q86UU0). Compare it with a no-primary control and review tissue edges and detection conditions for artefact (general IHC practice). Cytoplasmic staining alone is less decisive because HPA reports cytoplasmic tissue staining (HPA: tissue IHC, uncertain).
Adipocytes or bone-marrow hematopoietic cells stain as strongly as the expected positive cells.HPA scores those cell populations not detected, making the result a specificity warning rather than proof of BCL9L in them (HPA: tissue IHC, uncertain). Check for antibody cross-reactivity and signal from the detection system with matched controls (general IHC practice); the HPA comparison is provisional because its IHC reliability is uncertain (HPA: tissue IHC).
Brown signal coats broad areas of a chromogenic section without clear nuclear or cellular boundaries.Diffuse background cannot establish which cells express BCL9L or whether signal is nuclear (general IHC practice). Inspect a no-primary control, blocking, washes, and the detection reagent before assigning a positive score (general IHC practice); assess any remaining cell-specific signal against HPA's reported nuclear and cytoplasmic profile (HPA: tissue IHC, uncertain).
An adrenal glandular-cell or kidney tubule-cell section has no interpretable staining.These are useful positive comparators because HPA reports high staining in those specific cells (HPA: tissue IHC, uncertain). A blank result calls for checks of tissue preservation, retrieval conditions, antibody use, and chromogenic detection (general IHC practice); it does not by itself show that BCL9L is absent, particularly given the uncertain HPA IHC profile (HPA: tissue IHC).
💡Expected BCL9L appearanceA persuasive positive is discernible nuclear staining in HPA high cell populations such as adrenal glandular or kidney tubule cells, with any cytoplasmic component recorded separately; membrane-dominant or control-matched diffuse signal is suspect (UniProt Q86UU0; HPA: tissue IHC, uncertain; general IHC practice).
How each factor affects the staining
Tissue comparison and confidence (HPA: tissue IHC)HPA calls its IHC profile uncertain because staining and RNA expression have low consistency, despite high staining in several epithelial and glandular populations (HPA: tissue IHC). Use the named cell populations as comparators and avoid treating one tissue score as a definitive sensitivity or specificity standard.
Compartment and topology (UniProt Q86UU0; HPA: subcellular)UniProt places BCL9L in the nucleus and lists no transmembrane segment (UniProt Q86UU0). HPA's supported ICC-IF location is mainly nucleoplasmic, with an additional nucleolar fibrillar-center signal (HPA: subcellular). Tissue IHC may also show cytoplasmic staining, so compartment calls should preserve that source-specific difference (HPA: tissue IHC, uncertain).
Isoforms and modifications (UniProt Q86UU0)UniProt lists 4 isoforms and multiple modified residues (UniProt Q86UU0). The supplied record gives no antibody epitope or isoform-specific IHC validation, so it cannot predict which isoform contributes to a stained section or whether a modification alters staining. Report the observed pattern without assigning it to an isoform.
IF/ICC Q&A: where should BCL9L appear? (HPA: subcellular)Mainly in the nucleoplasm, with additional signal in the nucleoli fibrillar center (HPA: ICC-IF supported). That supported ICC-IF observation helps interpret localization, while HPA's tissue IHC profile remains uncertain and includes cytoplasmic staining (HPA: tissue IHC).
Why is my staining missing, weak or wrong?
SituationLikely causeNext action
No signal in the selected positive comparator.The comparator may lack interpretable cells, or the IHC workflow may have failed; HPA reports high staining specifically in adrenal glandular cells and kidney tubule cells (HPA: tissue IHC, uncertain).Verify the intended cell population on the section, then check retrieval, antibody application, detection, and counterstain against a working control (general IHC practice). Keep the HPA reliability rating in the interpretation (HPA: tissue IHC, uncertain).
Only a sharply membranous pattern is visible.That distribution conflicts with the nuclear annotation and no-transmembrane topology (UniProt Q86UU0); tissue IHC instead reports nuclear and cytoplasmic staining (HPA: tissue IHC, uncertain).Inspect a no-primary control and section edges, then reassess whether staining follows cells or a tissue artefact (general IHC practice). Do not score membrane-only signal as the expected BCL9L pattern.
Cytoplasmic signal appears without obvious nuclear staining.HPA reports cytoplasmic tissue staining, so cytoplasm alone is not automatically artefactual, although UniProt and supported ICC-IF favor nuclear localization (HPA: tissue IHC, uncertain; UniProt Q86UU0; HPA: subcellular).Score nuclear and cytoplasmic compartments separately, inspect cell boundaries and counterstain, and compare the same run with a named positive tissue and a no-primary control (general IHC practice).
A nominally negative population is strongly stained.HPA scores adipocytes and bone-marrow hematopoietic cells not detected; a strong signal there raises a specificity or detection-background concern, subject to HPA's uncertain IHC reliability (HPA: tissue IHC).Compare positive and negative populations under the same detection conditions and review the no-primary control (general IHC practice). Investigate antibody cross-reactivity if the signal persists after detection background is excluded (general IHC practice).
Diffuse chromogen obscures nuclei and tissue boundaries.Broad background prevents a compartment or cell-type call (general IHC practice). If an enzyme-based detection system is used, endogenous tissue activity can also contribute to signal (general IHC practice).Review blocking, washes, detection reagents, and the no-primary control; check the system's endogenous-activity control where applicable (general IHC practice). Rescore only signal whose cellular location can be resolved.
Staining varies across tissues or from the HPA examples.HPA reports low tissue RNA specificity and rates tissue IHC uncertain because staining and RNA expression show low consistency (HPA: tissue IHC). Tissue-level comparisons alone therefore cannot establish a technical failure.Record the exact stained cell type, compartment, and intensity; compare matched controls and repeat the relevant tissue comparison if needed (general IHC practice). Describe any discrepancy as unresolved rather than assigning BCL9L expression from staining alone (HPA: tissue IHC, uncertain).

Sample controls for BCL9L IHC & IF

🧪Run kidney first: tubular cells should stain (HPA: High in kidney tubular cells). Use adipose tissue as the negative tissue, focusing on adipocytes (HPA: Not detected in adipocytes); on the kidney slide, use any unstained interstitial cells as a background reference without assuming they are a validated biological negative (HPA: kidney result specifies tubular 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 BCL9L in CACO-2, MCF-7, U2OS, NIH 3T3, with annotated localisation: Nucleoplasm (supported) (HPA subcellular).
Technical controls: Include a no-primary (secondary-only) control, a control immunoglobulin matched to the primary antibody’s host species and, for a monoclonal antibody, isotype, plus a BCL9L knockout sample processed alongside the test sections (standard IHC practice). Block endogenous peroxidase and account for endogenous biotin in kidney when using biotin-based detection, since either can produce chromogenic background (standard IHC practice).
⚠️Feasibility: A target-specific fixation window and antigen-retrieval dependency are unreported in the supplied evidence; the selected A05905-1 breast-tissue IHC caption also leaves the fixative unreported (selected tissue-IHC caption). Whether frozen sections or IF are easier than paraffin IHC is undetermined, although ICC-IF images support nucleoplasmic localization (HPA: supported nucleoplasmic location). In kidney, endogenous biotin can complicate biotin-based chromogenic detection of tubular staining (standard IHC practice).

HPA tissue IHC evidence for BCL9L

Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Uncertain — 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

TissueCell typeLevelEvidenceSource
Adrenal gland Glandular cells High Protein (IHC) HPA →
Cervix Squamous epithelial cells High Protein (IHC) HPA →
Esophagus Squamous epithelial cells High Protein (IHC) HPA →
Kidney Cells in tubules High Protein (IHC) HPA →
Oral mucosa Squamous epithelial cells High Protein (IHC) HPA →

Undetected expression · recommended negative controls

TissueCell typeLevelEvidenceSource
Adipose tissue Adipocytes Not detected Protein (IHC) HPA →
Appendix Glandular cells Not detected Protein (IHC) HPA →
Bone marrow Hematopoietic cells Not detected Protein (IHC) HPA →
Caudate Glial cells Not detected Protein (IHC) HPA →
Cerebral cortex Endothelial cells Not detected Protein (IHC) HPA →
Section 3

Advanced BCL9L IHC Tips

Troubleshoot BCL9L chromogenic IHC by checking retrieval, nuclear localisation, tissue context and controls before interpreting staining intensity.

How should I optimise retrieval when BCL9L nuclear staining is weak?
Start with Tris-EDTA pH 9.0 heat-induced epitope retrieval at 95–98 °C for 20 min (page retrieval rule: nuclear antigen). Keep section thickness, cooling, antibody incubation and chromogen development consistent while comparing adjacent sections (standard IHC practice). If nuclear staining remains weak, test a citrate buffer at pH 6.0 as a fallback on matched sections, checking whether background also rises (standard IHC practice). Judge improvement in viable cells with expected nuclear staining, because BCL9L is annotated as nuclear and the supported subcellular location is the nucleoplasm (UniProt Q86UU0; HPA subcellular). Record the retrieval condition alongside the final staining score so samples remain comparable (standard IHC practice).
Could fixation explain loss of BCL9L staining in paraffin sections?
The selected breast-tissue IHC caption reports antibody at 5 µg/ml but gives no fixative, so BCL9L-specific fixation sensitivity is unknown (caption: A05905-1). Do not infer a fixation effect from tissue staining patterns or from BCL9L localisation and modifications (HPA tissue IHC; UniProt Q86UU0). For paraffin IHC, document fixation and processing for each specimen, then compare matched sections processed and stained together (standard IHC practice). If staining varies across blocks, first check retrieval, section integrity and detection controls before attributing the difference to fixation (standard IHC practice). Interpret any fixation comparison as an assay result for those specimens, rather than an established BCL9L property (caption: A05905-1).
Should BCL9L staining be nuclear or cytoplasmic?
Prioritise staining in viable nuclei: BCL9L is annotated as nuclear, with supported nucleoplasmic localisation and an additional nucleolar fibrillar-center location (UniProt Q86UU0; HPA subcellular). Tissue IHC also reports nuclear and cytoplasmic expression, but its reliability is uncertain because staining has low consistency with RNA expression (HPA tissue IHC). Evaluate nuclear and cytoplasmic signal separately rather than combining them into one positive score (standard IHC practice). Compare the same cell type across sections; keratinocytes in skin are reported as high, whereas adipocytes are reported as not detected (HPA tissue IHC). Diffuse cytoplasmic signal without convincing nuclear staining warrants a background and specificity check before biological interpretation (UniProt Q86UU0; standard IHC practice).
Could isoforms or epitope accessibility change the IHC pattern?
BCL9L has 4 annotated isoforms, but the supplied antibody evidence does not identify its epitope or establish isoform-specific staining (UniProt Q86UU0; caption: A05905-1). The record includes phosphorylation at residues 21 and 25 and acetylation at residue 36; effects on this antibody's binding are unknown (UniProt Q86UU0). If staining differs between specimens, check whether retrieval and detection conditions were identical before proposing an isoform explanation (standard IHC practice). An epitope-mapping result or independently validated antibody could then test that explanation on adjacent sections (standard IHC practice). Report the observed compartment and cell type without assigning an isoform from chromogenic staining alone (standard IHC practice).
How can IF help assess an ambiguous BCL9L IHC pattern?
Use IF/ICC as a separate localisation check: images are listed for CACO-2, MCF-7, U2OS and NIH 3T3, and the supported main location is nucleoplasmic (HPA subcellular). For tissue multiplexing, pair BCL9L with a marker identifying the expected cell type, such as an epithelial marker when assessing reported keratinocyte staining (HPA tissue IHC; standard IF practice). Choose a spectrally separated far-red fluorophore when tissue autofluorescence obscures shorter wavelengths, and include single-channel controls (standard IF practice). Because BCL9L has no transmembrane segment and is nuclear, permeabilise fixed specimens sufficiently for antibody access to the nucleus (UniProt Q86UU0; standard IF practice). Establish IF fixation conditions independently; the selected tissue-IHC caption does not state a fixative (caption: A05905-1).
What causes diffuse brown staining around BCL9L-positive cells?
Check a no-primary control for detection background and inspect whether brown precipitate follows tissue edges, damaged regions or endogenous pigment (standard chromogenic IHC practice). Block endogenous peroxidase before horseradish-peroxidase detection and develop DAB consistently across matched sections (standard chromogenic IHC practice). The breast-tissue caption documents staining at 5 µg/ml, which provides a reported concentration for that image rather than an established optimum for every specimen (caption: A05905-1). If background persists, compare lower primary-antibody concentrations and shorter chromogen development while retaining a reference section (standard IHC practice). Require discernible staining in viable nuclei before calling diffuse brown signal BCL9L, given its nuclear annotation (UniProt Q86UU0; standard IHC practice).
How should BCL9L chromogenic staining be scored across samples? ⚠ ANSWER MARKED FOR VERIFICATION
Define the scored cell population and compartment before reviewing groups; nuclear staining is the primary readout supported by the BCL9L localisation record (UniProt Q86UU0; HPA subcellular). Score viable-cell nuclear intensity from 0–3 and calculate an H-score as the sum of each intensity multiplied by its percentage of cells, giving 0–300 (standard IHC scoring practice). Alternatively, report percentage-positive nuclei using a prespecified threshold and keep any cytoplasmic score separate (standard IHC practice). Normalise counts to viable nuclei in comparable regions, or report positive-cell density per mm² with the sampled area specified (standard image-analysis practice). Document exclusions for folds, necrosis and edges, since HPA tissue-IHC reliability is uncertain (standard IHC practice; HPA tissue IHC).
When is an apparent BCL9L-positive IHC result credible?
A credible result shows reproducible staining in viable cells with a convincing nuclear component, consistent with BCL9L's nuclear annotation and supported nucleoplasmic location (UniProt Q86UU0; HPA subcellular). Check cell identity: HPA reports high staining in kidney tubular cells and skin keratinocytes, but its overall tissue-IHC reliability is uncertain (HPA tissue IHC). Treat staining confined to cut edges, necrotic areas or the no-primary control as an artefact candidate (standard IHC practice). If brown signal remains after omitting primary antibody, investigate endogenous enzyme activity and detection reagents before assigning positivity (standard chromogenic IHC practice). Describe any cytoplasmic staining separately, because the HPA tissue profile includes it but does not resolve its specificity (HPA tissue IHC).
Boster reagents

Best BCL9L / B-cell CLL/lymphoma 9-like protein IHC Antibodies

Anti-BCL9L IHC images cover human breast and cancer tissues and rat kidney; IF/ICC images cover human breast tissue, HeLa and A431 cells (catalog image captions).

Real IHC data Immunohistochemistry of Bcl9L in human breast tissue with Bcl9L antibody at 5 μg/ml.
Anti-Bcl9L Antibody
Cat # A05905-1

The rendered card is A05905-1, which lists human IHC-P and shows staining in human breast tissue (A05905-1 applications, reactivity and IHC image caption). It also lists IF and ICC, with images from human breast tissue and HeLa cells (A05905-1 applications and IF image captions).

Which to pick: For human tissue IHC, A05905 has captioned paraffin-section images from lung, ovarian and oesophageal cancers, while A05905-1 lists IHC-P and shows breast tissue staining without reporting how that tissue was processed (A05905 and A05905-1 applications and IHC image captions). For IF/ICC, choose A05905-1: both applications are listed and both have images; clonality is unreported for both SKUs (A05905-1 applications and IF image captions; catalog clone fields). For cross-species IHC, choose A05905: its listed reactivity includes human, mouse and rat, with paraffin-section images from human tissues and rat kidney; no mouse IHC image is supplied, and the IHC captions do not report fixative (A05905 reactivity and IHC image captions).

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

References

  1. UniProt Consortium. UniProt entry Q86UU0 (BCL9L_HUMAN, B-cell CLL/lymphoma 9-like protein).
  2. Human Protein Atlas. BCL9L tissue IHC expression (reliability: Uncertain).
  3. Human Protein Atlas. BCL9L subcellular location (ICC-IF): Mainly localized to the nucleoplasm. In addition localized to the nucleoli fibrillar center..
  4. Human Protein Atlas. BCL9L antibody validation summary (2 antibodies).
  5. miR-766-3p Targeting BCL9L Suppressed Tumorigenesis, Epithelial-Mesenchymal Transition, and Metastasis Through the β-Catenin Signaling Pathway in Osteosarcoma Cells. Frontiers in cell and developmental biology 2020 — PMC7575756.
  6. Wnt/β-Catenin Signalling and Its Cofactor BCL9L Have an Oncogenic Effect in Bladder Cancer Cells. International journal of molecular sciences 2022 — PMC9141496.
  7. Role of BCL9L in transforming growth factor-β (TGF-β)-induced epithelial-to-mesenchymal-transition (EMT) and metastasis of pancreatic cancer. Oncotarget 2016 — PMC5342010.
  8. Cell softness regulates tumorigenicity and stemness of cancer cells. The EMBO journal 2021 — PMC7809788.
  9. PubMed PMID:15371335 — UniProt-cited evidence.
  10. PubMed PMID:15489334 — UniProt-cited evidence.
  11. PubMed PMID:14702039 — UniProt-cited evidence.