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CBX8 / Chromobox protein homolog 8 · IHC design guide
Design Immunohistochemistry for CBX8
Plan CBX8 staining in paraffin sections using nuclear localisation as the molecular expectation (UniProt) and nuclear plus cytoplasmic staining as the observed tissue pattern (HPA tissue IHC). Rectal glandular cells stain strongly, while ovarian stromal cells are reported as undetected (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
CBX8 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 expected (UniProt); nuclear and cytoplasmic staining observed (HPA tissue IHC) | |
| Staining pattern | General cytoplasmic and nuclear staining (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A05234-2) | |
| Positive control | Bone marrow+4 more · see all | |
| Negative control | Hippocampus+3 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections. (standard IHC practice; not target-specific) | |
| Caveat | Antibody staining and RNA show medium consistency (HPA tissue IHC) | |
| Regulation | Low tissue specificity (HPA tissue RNA) | |
| Isoform / epitope | No annotated isoforms; one 1–389 chain (UniProt) |
Section 1
Recommended CBX8 IHC & IF Protocols
The catalog antibody protocol is followed by published CBX8 IHC methods for hepatocellular carcinoma and colorectal cancer specimens (PMC6361915; PMC4279409).
| Sample | Paraffin-embedded human rectal cancer tissue; fixative not specified (datasheet A05234-2) |
| Fixation | Image fixative and duration unreported (datasheet A05234-2); 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 A05234-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A05234-2) |
| Primary antibody | Rabbit anti-CBX8, 0.5-1μg/ml (datasheet A05234-2) |
| Primary incubation | Overnight at 4 °C (datasheet A05234-2) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A05234-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | CBX8-positive staining in hematopoietic cells of bone marrow (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic and nuclear expression. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA at pH 8.0 for antigen retrieval (datasheet A05234-2); the included article excerpts do not specify retrieval conditions.
Section 2
What Is the Expected CBX8 Staining Pattern?
CBX8 is a nuclear protein with no transmembrane segment (UniProt Q9HC52: subcellular location and topology). In paraffin-section IHC, HPA reports general cytoplasmic and nuclear staining, with high staining in colon glandular cells, bone-marrow hematopoietic cells and several other specified cell populations (HPA: tissue IHC). Treat the pattern as a guide to interpretation: HPA rates its IHC evidence Approved, with medium consistency between staining and RNA expression (HPA: tissue IHC reliability).
| Nuclear staining in colon glandular cells, with some cytoplasmic staining. | This fits the reported high level in colon glandular cells and HPA’s general nuclear-and-cytoplasmic IHC profile (HPA: tissue IHC). Nuclear localisation also agrees with UniProt (UniProt Q9HC52: subcellular location). Compare cells within the same section before judging intensity. |
| Strong cytoplasmic staining with little or no nuclear signal. | Interpret cautiously: HPA reports a cytoplasmic component in tissue IHC, but UniProt places CBX8 in the nucleus and HPA ICC-IF localises it to the nucleoplasm (HPA: tissue IHC and subcellular; UniProt Q9HC52). Review controls before accepting a cytoplasm-only result. |
| Staining in cholangiocytes, while the expected cell population is unclear. | HPA lists liver cholangiocytes as not detected, so staining there warrants review for cross-reactivity or endogenous chromogen activity (HPA: tissue IHC; general IHC practice). That observation alone does not establish either cause or mean that every liver cell must be negative. |
| Broad, diffuse colour obscures nuclei and tissue boundaries. | The distribution cannot be scored reliably for the reported CBX8 compartments or cell populations (HPA: tissue IHC). Inspect a control without primary antibody and assess blocking, washing and detection background before assigning cellular staining (general IHC practice). |
| No signal in colon glandular cells or bone-marrow hematopoietic cells. | Both are listed as High by HPA, making them useful reference populations for a failed or weak run (HPA: tissue IHC). Check that the reference cells are present, then review detection and the catalog antibody’s IHC-P instructions (general IHC practice). |
💡Expected CBX8 appearanceA convincing positive shows clear nuclear staining in a reported High population, such as colon glandular cells, with possible cytoplasmic staining (HPA: tissue IHC; UniProt Q9HC52: nucleus); uniform diffuse colour or staining confined to an HPA not-detected cell population should prompt a control check (HPA: tissue IHC; general IHC practice).
| Compartment evidence | UniProt assigns CBX8 to the nucleus, and HPA ICC-IF refines this to the nucleoplasm; HPA tissue IHC reports nuclear plus cytoplasmic staining (UniProt Q9HC52; HPA: subcellular and tissue IHC). Use this distinction when evaluating a cytoplasm-only IHC result. |
| Cell-population reference | HPA reports High staining in rectal glandular cells, skin melanocytes and round or early testicular spermatids, among other listed populations (HPA: tissue IHC). Its not-detected calls apply to named populations, including hippocampal glial cells and liver cholangiocytes, rather than entire organs (HPA: tissue IHC). |
| Evidence strength | The tissue IHC profile is Approved with medium staining-to-RNA consistency; the listed antibody HPA031462 has IHC Approved and ICC Enhanced status (HPA: tissue IHC and antibodies). ICC enhancement does not upgrade the IHC validation status, so assess each application against its own evidence. |
| Protein structure and epitope limits | UniProt records one chain spanning residues 1–389, a chromo domain at 11–69, no annotated isoforms and no signal peptide or propeptide (UniProt Q9HC52). These annotations do not identify this antibody’s epitope or establish a CBX8-specific antigen-retrieval condition. |
| Chromogenic background | Endogenous enzyme activity or nonspecific detection can contribute colour independently of primary-antibody binding (general IHC practice). A control without primary antibody helps distinguish this background from the cell-specific HPA pattern; it cannot by itself prove that all remaining staining is CBX8-specific (HPA: tissue IHC; general IHC practice). |
| Situation | Likely cause | Next action |
|---|---|---|
| High reference tissue stains weakly or not at all. | The expected cells may be absent from the section, or the IHC detection run may have failed (HPA: High in colon glandular cells and bone-marrow hematopoietic cells; general IHC practice). | Confirm the named cells are present; check the catalog antibody’s IHC-P instructions, reagent activity and detection controls before interpreting the sample as CBX8-negative (general IHC practice). |
| Signal appears only in cytoplasm. | HPA tissue IHC includes cytoplasmic staining, while UniProt and HPA ICC-IF support a nuclear location (HPA: tissue IHC and subcellular; UniProt Q9HC52). The discrepancy alone does not identify its cause. | Compare nuclear and cytoplasmic signal in a reported High cell population and inspect the control without primary antibody; qualify a cytoplasm-only result if nuclear signal remains absent (HPA: tissue IHC; general IHC practice). |
| A not-detected reference population stains strongly. | For example, HPA reports ovarian stroma cells as not detected; cross-reactivity or endogenous detection activity are possible explanations, not established diagnoses (HPA: tissue IHC; general IHC practice). | Verify the stained cell identity, compare a reported High population in the same run and inspect the control without primary antibody before assigning the signal to CBX8 (HPA: tissue IHC; general IHC practice). |
| Brown colour spreads across tissue without clear cell boundaries. | Diffuse deposition or nonspecific detection may prevent compartment-level scoring (general IHC practice). It cannot be matched confidently to HPA’s reported nuclear-and-cytoplasmic cell pattern (HPA: tissue IHC). | Inspect the control without primary antibody and review blocking, washing and chromogen development under the IHC workflow; score only interpretable cellular staining (general IHC practice). |
| A low-staining population is treated as a negative control. | HPA labels lung macrophages, small-intestinal glandular cells and adipocytes Low, rather than not detected (HPA: tissue IHC). Residual staining in these populations is therefore compatible with the supplied profile. | Use HPA’s named not-detected populations for a closer comparison, while keeping the call specific to those cells; retain a separate control without primary antibody for detection background (HPA: tissue IHC; general IHC practice). |
| IF/ICC question: What location should a separate fluorescence image show? | HPA’s ICC-IF summary localises CBX8 to the nucleoplasm, and HPA031462 has ICC Enhanced status (HPA: subcellular and antibodies). These are fluorescence observations, separate from the Approved tissue IHC profile. | Look for nucleoplasmic signal when interpreting IF/ICC images (HPA: subcellular); use the dedicated IF/ICC guide for that application, while interpreting paraffin IHC against the tissue IHC evidence (HPA: tissue IHC). |
Experiment evidence
IHC & IF images showing CBX8 staining
A05234-2 · IHCIHC analysis of Cbx8 using anti-Cbx8 antibody (A05234-2). Cbx8 was detected in paraffin-embedded section of human rectal cancer tissue. Heat
A05234-2 · IHCIHC analysis of Cbx8 using anti-Cbx8 antibody (A05234-2). Cbx8 was detected in paraffin-embedded section of human rectal cancer tissue. Heat
A05234-2 · IFIF analysis of Cbx8 using anti-Cbx8 antibody (A05234-2). Cbx8 was detected in immunocytochemical section of A549 cells. Enzyme antigen retri
M05234 · IHCIHC analysis of Cbx8 using anti-Cbx8 antibody (M05234). Cbx8 was detected in paraffin-embedded section of human gallbladder adenocarcinoma t
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000141570-CBX8/tissue/cerebral+cortex#imid_8036751
HPA · BronchusHuman Protein Atlas IHC, Bronchus. Source: https://www.proteinatlas.org/ENSG00000141570-CBX8/tissue/bronchus#imid_8036732
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000141570-CBX8/tissue/colon#imid_8037386
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000141570-CBX8/tissue/liver#imid_8037379
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA031462; green = CBX8, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA031462; green = CBX8, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for CBX8 IHC & IF
🧪Run colon first: glandular cells should show nuclear CBX8 staining (High; HPA: colon glandular cells; UniProt Q9HC52: nucleus). Use parathyroid glandular cells as a negative tissue (Not detected; HPA: parathyroid glandular cells); cells independently confirmed as negative within the colon section should show counterstain without nuclear chromogen (standard IHC practice).
Positive control tissue: Bone marrow (Hematopoietic cells, HPA High)
Negative control tissue: Hippocampus (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show CBX8 in A-431, U-251MG, U2OS, HeLa BAC 5991, HeLa , with annotated localisation: Nucleoplasm (enhanced) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control; an isotype-matched rabbit IgG control matched to the primary antibody’s clonality where known; and CBX8-knockout tissue or cells as a biological negative (selected-SKU caption: rabbit primary; standard IHC practice). Quench endogenous peroxidase and check for endogenous biotin when using the caption’s biotinylated secondary and SABC detection on colon sections (selected-SKU caption: SABC with DAB; standard IHC practice).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported in the supplied evidence, and the selected-SKU paraffin-section caption leaves the fixative unreported (selected-SKU caption: A05234-2). Start with heat retrieval in EDTA pH 8.0, as reported in that caption; whether CBX8 staining depends on this retrieval condition is unreported (selected-SKU caption: A05234-2). The supplied evidence does not establish that frozen sections or IF/ICC are easier than paraffin IHC; for colon sections, assess gland-associated background and endogenous biotin before interpreting nuclear staining (HPA: colon glandular cells High; selected-SKU caption: SABC with DAB; standard IHC practice).
HPA tissue IHC evidence for CBX8
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — 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 |
|---|---|---|---|---|
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Bronchus | Ciliated cells (cell body) | High | Protein (IHC) | HPA → |
| Colon | Glandular cells | High | Protein (IHC) | HPA → |
| Fallopian tube | Ciliated cells (cell body) | High | Protein (IHC) | HPA → |
| Nasopharynx | Ciliated cells (cell body) | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Hippocampus | Glial cells | Not detected | Protein (IHC) | HPA → |
| Liver | Cholangiocytes | Not detected | Protein (IHC) | HPA → |
| Ovary | Ovarian stroma cells | Not detected | Protein (IHC) | HPA → |
| Parathyroid gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced CBX8 IHC Tips
Troubleshoot CBX8 staining in paraffin sections by checking retrieval, nuclear localisation, detection controls and cell-specific scoring.
What retrieval should I try first for weak CBX8 staining?
Use heat-mediated retrieval in EDTA at pH 8.0 for paraffin-section CBX8 IHC (datasheet A05234-2). The selected tissue image used that condition before incubation with 1 μg/ml primary antibody overnight at 4°C, so reproduce those steps when investigating a weak result (caption A05234-2). Record heating and cooling conditions, then compare sections processed together with the same detection reagents; differences in retrieval exposure can change staining (standard IHC practice). If signal remains weak, optimise heating within the EDTA method while checking tissue morphology and a known positive control, such as rectal glandular cells (HPA: High in rectal glandular cells; standard IHC practice).
Could fixation explain inconsistent CBX8 staining between paraffin blocks?
Target-specific sensitivity of CBX8 to fixation is unknown from the supplied evidence; the selected paraffin-section caption does not state a fixative (caption A05234-2). Record each block’s fixative, fixation duration and processing history before attributing staining differences to CBX8 biology (standard IHC practice). Compare blocks using the same EDTA retrieval at pH 8.0, 1 μg/ml primary concentration and overnight incubation at 4°C used in the selected image (caption A05234-2). Include similarly processed positive tissue and assess morphology alongside signal, because inconsistent preparation or damaged sections can confound an IHC comparison (standard IHC practice).
Should I accept cytoplasmic CBX8 staining when scoring IHC?
Prioritise nuclear staining when assessing CBX8, which is annotated in the nucleus (UniProt Q9HC52), with enhanced nucleoplasmic localisation reported by subcellular imaging (HPA subcellular). Tissue IHC also reports a general cytoplasmic and nuclear pattern, with medium consistency between staining and RNA expression, so cytoplasmic signal warrants separate evaluation (HPA tissue IHC). Score nuclear and cytoplasmic compartments independently in the relevant cells, keeping thresholds and counterstain assessment consistent across sections (standard IHC practice). If cytoplasmic staining dominates, inspect no-primary controls, section edges and detection background before treating that pattern as CBX8 expression (standard IHC practice).
How should the CBX8 epitope affect troubleshooting in tissue sections?
The supplied record lists 0 annotated CBX8 isoforms and a chromo domain spanning residues 11–69, but it does not identify this antibody’s epitope (UniProt Q9HC52; datasheet A05234-2). It also records phosphoserines at residues 110, 130, 191, 256 and 265; their effect on this antibody’s tissue staining is unreported (UniProt Q9HC52). Do not assign a weak or shifted staining pattern to an isoform or modification without epitope information and independent validation (standard IHC practice). Compare retrieval conditions and appropriate positive and negative controls first, while documenting which cellular compartment each candidate signal occupies (standard IHC practice).
How can IF help check an ambiguous CBX8 IHC pattern?
Use IF as a complementary localisation check for ambiguous chromogenic staining, while keeping the selected antibody’s documented tissue method anchored to paraffin-section IHC (caption A05234-2; standard IHC practice). Multiplex CBX8 with a validated marker for the expected cell population, such as rectal glandular cells, which show high CBX8 tissue staining (HPA: High in rectal glandular cells). Choose fluorophores and controls that distinguish signal from tissue autofluorescence, and evaluate channels separately before calling overlap (standard IF practice). For an intracellular nuclear epitope, include suitable permeabilisation; CBX8 is nuclear and has no transmembrane segment, although this antibody’s precise epitope is unspecified (UniProt Q9HC52; standard IF practice).
What should I check when CBX8 DAB staining looks diffuse?
The selected IHC image used 10% goat serum blocking, a biotinylated secondary antibody, streptavidin–biotin detection and DAB chromogen (caption A05234-2). When diffuse colour obscures nuclei, compare no-primary and secondary-only controls to assess detection-related background (standard IHC practice). Include a peroxidase block as a general chromogenic IHC step, and consider an avidin/biotin blocking control if background tracks the biotin-based detection system; neither step is documented as CBX8-specific evidence here (standard IHC practice). Review primary concentration against the documented 1 μg/ml, wash conditions and section edges before increasing antibody exposure, and judge signal against preserved cellular morphology (caption A05234-2; standard IHC practice).
How should I quantify CBX8 across differently cellular tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and score nuclear CBX8 separately from any cytoplasmic signal, given its nuclear annotation and the mixed tissue staining profile (UniProt Q9HC52; HPA tissue IHC). For nuclear staining, report the percentage of positive viable cells and, when intensity is reliable, an H-score on a 0–300 scale (standard IHC practice). If reporting positive-cell density per mm², normalise to the analysed viable tissue area and describe how necrotic regions and section edges were excluded (standard IHC practice). Keep thresholds, magnification and sampling consistent, and compare matched cell types rather than whole-section averages when tissue composition differs (standard IHC practice).
How can I distinguish genuine CBX8 positivity from IHC artefact?
A convincing result follows cellular anatomy and includes nuclear signal, consistent with CBX8’s nuclear annotation and enhanced nucleoplasmic localisation (UniProt Q9HC52; HPA subcellular). Rectal glandular cells are a useful expected-positive population, whereas HPA reports cholangiocytes as not detected; these observations guide control selection without proving antibody specificity (HPA: High in rectal glandular cells; HPA: Not detected in cholangiocytes). Treat isolated edge staining, colour over necrosis or signal in no-primary controls as possible artefact, and check endogenous enzyme background in the DAB workflow (standard IHC practice). Evaluate cytoplasmic signal separately because tissue IHC reports both compartments, and seek independent confirmation before assigning a disputed pattern to CBX8 (HPA tissue IHC; standard IHC practice).
Boster reagents
Best CBX8 / Chromobox protein homolog 8 IHC Antibodies
The catalog documents CBX8 staining in human paraffin sections and cells, plus mouse and rat paraffin sections (A05234-2 and M05234 IHC captions; A05234-2 IF captions).
Real IHC data
Anti-Cbx8 Antibody ®
Cat # A05234-2
Real IHC data
Anti-Cbx8 Antibody ® (monoclonal, 8G7)
Cat # M05234
A05234-2 has IHC data from human rectal cancer and mouse and rat small intestine paraffin sections, plus IF data from A549 cells and human rectal cancer paraffin sections (A05234-2 image captions). M05234 has IHC data from human gallbladder adenocarcinoma paraffin sections (M05234 IHC caption).
Which to pick: For tissue IHC, choose A05234-2 for human, mouse or rat paraffin sections (A05234-2 IHC captions), or monoclonal M05234 for human paraffin sections (M05234 catalog entry and IHC caption). For IF/ICC, choose A05234-2, which lists both applications and has human cell and paraffin-section IF images (A05234-2 catalog entry and IF captions). For cross-species IHC, choose A05234-2 because its IHC captions show all three species (A05234-2 IHC captions); the fixative is unreported in both products’ paraffin-section captions (A05234-2 and M05234 IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9HC52 (CBX8_HUMAN, Chromobox protein homolog 8).
- Human Protein Atlas. CBX8 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. CBX8 subcellular location (ICC-IF): Localized to the nucleoplasm..
- Human Protein Atlas. CBX8 antibody validation summary (1 antibodies).
- The co-expression of CBX8 and PD-L1 and prognostic value in cervical cancer. Medicine 2021 — PMC10545086.
- CBX8 exhibits oncogenic properties and serves as a prognostic factor in hepatocellular carcinoma. Cell death & disease 2019 — PMC6361915.
- Paradoxical role of CBX8 in proliferation and metastasis of colorectal cancer. Oncotarget 2014 — PMC4279409.
- Correlations between chromobox homolog 8 and key factors of epithelial-mesenchymal transition in hepatocellular carcinoma. Cancer cell international 2019 — PMC6916084.
- PubMed PMID:10825164 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for CBX8 (Chromobox protein homolog 8). Expected localisation Nuclear expected (UniProt); nuclear and cytoplasmic staining observed (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A05234-2). Validated IHC antibody: A05234-2 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Bone marrow (Hematopoietic cells); negative Hippocampus. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human rectal cancer tissue; fixative not specified (datasheet A05234-2); 2. Fixation: Image fixative and duration unreported (datasheet A05234-2); 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 A05234-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A05234-2); 8. Primary antibody: Rabbit anti-CBX8, 0.5-1μg/ml (datasheet A05234-2); 9. Primary incubation: Overnight at 4 °C (datasheet A05234-2). Watch for: Fixation: Keep fixation consistent across sections. (standard IHC practice; not target-specific); Caveat: Antibody staining and RNA show medium consistency (HPA tissue IHC); Isoform / epitope: No annotated isoforms; one 1–389 chain (UniProt); Regulation: Low tissue specificity (HPA tissue RNA). Evidence: UniProt Q9HC52, HPA tissue IHC · Approved, HPA ICC-IF · nucleoplasm., Datasheet A05234-2, PMC6361915, PMC4279409. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/CBX8/immunohistochemistry-ihc-guide.