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GCSAM / Germinal center-associated signaling and motility protein · IHC design guide
Design Immunohistochemistry for GCSAM
Plan GCSAM paraffin IHC around cytoplasmic immune-cell staining, using tonsil germinal-center cells as a positive control (HPA tissue IHC). Start catalog antibody M12995-1 within its 1:100–1:300 IHC dilution range (datasheet M12995-1).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
GCSAM 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 | Cytoplasm in tissue immune cells (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic immune-cell staining; tonsil GC cells medium (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 9.0 HIER, heat-mediated (datasheet M12995-1) | |
| Positive control | Cerebellum+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 | Antibody staining and RNA expression show low consistency (HPA tissue IHC) | |
| Regulation | GC enriched; IL6 alters localisation (UniProt) | |
| Isoform / epitope | 3 isoforms; no transmembrane segment; epitope impact unknown (UniProt) |
Section 1
Recommended GCSAM IHC & IF Protocols
The catalog antibody’s IHC-P protocol (datasheet M12995-1) is paired with one published FFPE tissue protocol (PMC10901781 methods).
| Sample | Paraffin-embedded human tonsil tissue; fixative not specified (datasheet M12995-1) |
| Fixation | Image fixative and duration unreported (datasheet M12995-1); 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 9.0, 20min (datasheet M12995-1) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% normal serum of the secondary host, 30 min, room temperature (standard) |
| Primary antibody | Rabbit anti-GCSAM, 1:100-1:300 (datasheet M12995-1) |
| Primary incubation | Overnight at 4 °C (standard) |
| Detection | HRP-polymer secondary, DAB chromogen 5–10 min (standard) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | GCSAM-positive staining in cells in molecular layer of cerebellum (HPA tissue IHC: Medium). HPA tissue profile: Cytoplasmic expression in immune cells. No signal in the no-primary control. |
💡Decision noteStart with EDTA pH 9.0 heat retrieval (datasheet M12995-1); the published method also uses pH 9.0 heat retrieval (PMC10901781 methods).
Section 2
What Is the Expected GCSAM Staining Pattern?
Expect GCSAM chiefly in the cytoplasm of germinal center lymphocytes, with cell membrane localization also possible (UniProt Q8N6F7 localization; HPA: cytoplasmic expression in immune cells). Tonsil germinal center cells show medium staining (HPA: tonsil). GCSAM has no transmembrane segment (UniProt Q8N6F7 topology). HPA rates its tissue IHC antibody Approved but reports low consistency between staining and RNA expression (HPA: tissue IHC reliability).
| Distinct cytoplasmic staining in tonsil germinal center cells. | This matches the reported tissue pattern; medium intensity is the HPA reference observation, not a required intensity for every section (HPA: tonsil, Medium; HPA: cytoplasmic expression in immune cells). Assess the stained cells against the germinal center on the same slide (general IHC practice). |
| Predominantly nuclear staining, with little cytoplasmic signal. | An isolated nuclear pattern conflicts with the reported cytoplasmic and cell membrane locations (UniProt Q8N6F7 localization; HPA: cytoplasmic expression in immune cells). Treat it as a possible staining artefact and review morphology, counterstain, controls and antibody specificity before assigning it to GCSAM (general IHC practice). |
| Strong staining in adipocytes or bone marrow hematopoietic cells. | Those cells were not detected in HPA tissue IHC, so prominent staining warrants a check for cross-reactivity or endogenous detection activity (HPA: adipocytes and bone marrow hematopoietic cells, Not detected; general IHC practice). Other nonimmune staining cannot automatically be dismissed: HPA reports medium staining in several nonimmune cell populations (HPA: tissue IHC positives). |
| Diffuse color covers cells and surrounding tissue without clear cell boundaries. | That appearance does not resolve the reported cytoplasmic immune cell pattern (HPA: tissue IHC profile). Evaluate it as background using a no-primary control and the section morphology; incomplete blocking, residual detection reagent or an overly strong detection reaction are general IHC possibilities, not documented GCSAM-specific effects (general IHC practice). |
| No staining in tonsil germinal center cells. | This misses an HPA-observed positive population, but one blank section does not establish absence of GCSAM (HPA: tonsil germinal center cells, Medium). Confirm that the germinal center is present, then check the positive control and detection workflow (general IHC practice). HPA's Approved rating includes a low staining–RNA consistency caveat (HPA: tissue IHC reliability). |
💡Expected GCSAM appearanceExpected positive: discernible, approximately medium cytoplasmic staining in tonsil germinal center cells; a nuclear-only pattern or uniform tissue-wide color is suspect (HPA: tonsil, Medium; HPA: cytoplasmic immune cell profile; UniProt Q8N6F7 localization; general IHC practice).
| Location and topology | GCSAM is annotated in cytoplasm and at the cell membrane, without a transmembrane segment (UniProt Q8N6F7 localization and topology). Read membrane-associated color in the context of a cell's cytoplasmic staining and morphology; topology alone cannot identify an antibody epitope (general IHC interpretation). |
| Tissue and antibody evidence | The tissue IHC profile is Approved, yet HPA notes low consistency between antibody staining and RNA expression; the listed antibody, HPA002473, is IHC Approved, not IHC Enhanced (HPA: tissue IHC reliability; HPA: antibody validation). Treat the listed positive and negative cells as observed references, not absolute specificity guarantees. |
| Isoforms and modifications | UniProt lists 3 isoforms and phosphorylation sites at residues 99 and 148 (UniProt Q8N6F7 isoforms and modified residues). The supplied sources do not map the IHC antibody's epitope or show isoform- or phosphorylation-dependent staining; do not interpret intensity differences as either effect. |
| Retrieval and processing | No target-specific antigen retrieval response or fixation sensitivity is supplied. UniProt annotates one 1–178 chain, no signal peptide and no propeptide (UniProt Q8N6F7 processing). Those annotations do not predict which retrieval condition will work in paraffin sections; optimize retrieval against controls (general IHC practice). |
| IF/ICC: What pattern is supported? | UniProt lists cytoplasm and cell membrane, with movement to podosome-like structures after IL6 treatment (UniProt Q8N6F7 localization). HPA provides no main ICC-IF location or cell-line images, and HPA002473 has no ICC validation listed (HPA: subcellular record; HPA: antibody validation). Therefore, no observed IF/ICC pattern can be promised here. |
| Situation | Likely cause | Next action |
|---|---|---|
| Tonsil germinal centers appear negative. | The positive cells may be absent from the section, or the IHC detection workflow may have failed; HPA observed medium staining in tonsil germinal center cells (HPA: tonsil; general IHC practice). | Verify germinal center morphology and an on-run positive control. Review the catalog antibody's IHC-P instructions for the applied dilution and retrieval conditions, then change one workflow variable at a time (general IHC practice). |
| The slide shows nuclear-only color. | The result conflicts with reported cytoplasmic and cell membrane localization; nonspecific staining or misread counterstain is possible (UniProt Q8N6F7 localization; HPA: tissue IHC profile; general IHC practice). | Compare with the counterstain and a no-primary control. Reassess antibody concentration and detection exposure before scoring nuclear color as GCSAM (general IHC practice). |
| Adipocytes or bone marrow hematopoietic cells stain strongly. | HPA reports these populations as not detected; cross-reactivity or endogenous detection activity is plausible, although HPA staining is not an absolute absence test (HPA: adipose tissue and bone marrow; general IHC practice). | Run no-primary and detection-only controls, inspect the cell identity and check the antibody's IHC validation. Record the discrepancy rather than treating it as a confirmed GCSAM-positive population (general IHC practice). |
| Color is diffuse across the section. | A tissue-wide haze obscures the reported cytoplasmic immune cell pattern (HPA: tissue IHC profile). Excess detection reaction or insufficient blocking are general IHC possibilities, without target-specific evidence here (general IHC practice). | Check a no-primary control, wash steps, blocking and chromogen development. Adjust the detection workflow using the same positive tissue as a reference (general IHC practice; HPA: tonsil). |
| Only a faint signal appears in tonsil. | HPA's reference is medium staining in germinal center cells, but section quality and workflow can affect visibility; no GCSAM-specific fixation effect is documented in the supplied sources (HPA: tonsil; general IHC practice). | Confirm the correct cell population and working positive control. Check retrieval, antibody dilution and detection against the catalog IHC-P instructions without assuming that fixation caused the weak result (general IHC practice). |
| An IF/ICC image seems inconsistent with the IHC slide. | HPA lists no ICC-IF images or main subcellular location, and the listed antibody has no ICC validation; UniProt's localization is a protein annotation rather than an image-based ICC result (HPA: subcellular record; HPA: antibody validation; UniProt Q8N6F7 localization). | Interpret the paraffin IHC slide against its own tissue controls and HPA tissue observations. Use the separate IF/ICC guide for fluorescence assay design (HPA: tissue IHC profile; general assay practice). |
Experiment evidence
IHC & IF images showing GCSAM staining
M12995-1 · IHCImmunohistochemical analysis of paraffin-embedded human tonsil tissue. 1,primary Antibody was diluted at 1:200(4°C,overnight). 2, EDTA pH 9.
M12995 · IHCImmunohistochemical analysis of paraffin-embedded human bladder cancer, using GCET2 Antibody.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000174500-GCSAM/tissue/cerebral+cortex#imid_1159832
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000174500-GCSAM/tissue/colon#imid_1159750
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000174500-GCSAM/tissue/liver#imid_1159751
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000174500-GCSAM/tissue/kidney#imid_1159760
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for GCSAM IHC & IF
🧪Run cerebral cortex first and score staining in neuronal cells, where HPA reports Medium GCSAM staining (HPA: cerebral cortex, neuronal cells, Medium). Run heart muscle as the negative tissue, where cardiomyocytes are Not detected (HPA: heart muscle, cardiomyocytes, Not detected); on the cortex slide, neighboring non-neuronal cells should show only background if used as internal negative cells, but their GCSAM status requires validation.
Positive control tissue: Cerebellum (Cells in molecular layer, HPA Medium)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for GCSAM; derive a cell-line control from the positive tissue's cell type (Cells in molecular layer) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only control; a host-species- and clonality-matched isotype control; and a biological negative such as GCSAM knockout tissue or a validated peptide block. For cerebral cortex, quench endogenous peroxidase before chromogenic detection and assess tissue autofluorescence when interpreting IF.
⚠️Feasibility: No target-specific fixation window or fixation effect is reported in the supplied evidence; the selected paraffin-section caption does not state a fixative (catalog antibody M12995-1 caption: fixative not stated). Its IHC procedure uses EDTA at pH 9.0 for retrieval at >98°C for 20 minutes (catalog antibody M12995-1 caption), so retrieval should be checked when adapting the procedure to cortex. The supplied evidence does not establish that frozen sections or IF are easier; neuronal lipofuscin autofluorescence can complicate cortical IF interpretation (standard IF practice).
HPA tissue IHC evidence for GCSAM
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — 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
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Cerebellum | Cells in molecular layer | Medium | Protein (IHC) | HPA → |
| Cerebral cortex | Neuronal cells | Medium | Protein (IHC) | HPA → |
| Hippocampus | Neuronal cells | Medium | Protein (IHC) | HPA → |
| Pancreas | Pancreatic endocrine cells | Medium | Protein (IHC) | HPA → |
| Placenta | Trophoblastic 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 → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Esophagus | Squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
| Heart muscle | Cardiomyocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced GCSAM IHC Tips
Troubleshoot GCSAM staining in paraffin sections by checking retrieval, cell identity, compartment, controls, and scoring before interpreting signal (datasheet M12995-1; UniProt Q8N6F7).
How should I retrieve GCSAM in paraffin sections when germinal center staining is weak?
Start with heat-mediated EDTA retrieval at pH 9.0 for GCSAM paraffin-section IHC (datasheet M12995-1). The selected tonsil image used EDTA at pH 9.0, above 98°C for 20 minutes, followed by primary antibody at 1:200 overnight at 4°C (caption M12995-1). If staining remains weak, compare a milder heating interval on adjacent sections while keeping antibody concentration and detection constant; excessive heating can damage morphology (standard IHC practice). Judge the result in germinal center cells, where tissue IHC shows medium staining, and include a no-primary control to distinguish recovered signal from background (HPA tissue IHC; standard IHC practice).
Could fixation explain absent GCSAM staining in a paraffin section?
GCSAM-specific fixation sensitivity is unknown: the selected paraffin tonsil caption does not report a fixative, and the supplied evidence gives no target-specific fixation comparison (caption M12995-1). Record the specimen’s actual fixative, fixation duration, and processing history before comparing staining between blocks, because those variables can affect antigen accessibility in IHC (standard IHC practice). Compare sections from similarly processed blocks using the documented pH 9.0 EDTA retrieval and 1:200 primary dilution as a starting condition (caption M12995-1). Preserve a known staining reference section in each run and interpret any fixation association as an experimental observation, not an established GCSAM property (standard IHC practice).
Where should chromogenic GCSAM signal appear, and how should membrane-adjacent staining be judged?
Expect mainly cytoplasmic staining in relevant immune cells on tissue IHC, while the protein record also lists cytoplasm and cell membrane (HPA tissue IHC; UniProt Q8N6F7 subcellular). GCSAM has no annotated transmembrane segment, so a sharp, exclusively circumferential stain deserves confirmation with an independent control rather than automatic acceptance as surface expression (UniProt Q8N6F7 topology; standard IHC practice). IL6 treatment can move GCSAM toward podosome-like structures, but that observation does not establish a routine pattern in paraffin tissue (UniProt Q8N6F7 subcellular). Compare cell-level staining within germinal centers against surrounding tissue, preserving nuclear counterstain and morphology to locate signal accurately (HPA tissue IHC; standard IHC practice).
How can isoforms or epitope masking affect a negative GCSAM IHC result?
GCSAM has 3 annotated isoforms, but the supplied product caption does not identify its recognized epitope or establish equal recognition of each isoform (UniProt Q8N6F7 isoforms; caption M12995-1). Its annotated phosphoserine at residue 99 and phosphotyrosine at residue 148 make modification status a consideration only if the antibody epitope overlaps those sites (UniProt Q8N6F7 modified residues; standard immunostaining interpretation). Do not attribute absent tissue staining to a particular splice form or phosphorylation state without epitope and validation data (standard IHC practice). First check the documented retrieval, staining reference, morphology, and no-primary control, then compare an independently characterized antibody if the result remains discordant (caption M12995-1; standard IHC practice).
How can IF help assess an ambiguous GCSAM chromogenic pattern?
On a separate IF/ICC experiment, multiplex GCSAM with a validated germinal center B-cell marker to test whether signal occupies the expected cells (UniProt Q8N6F7 tissue specificity; standard IF practice). Select a fluorophore channel with low measured tissue autofluorescence, and assess single-stain and no-primary controls before interpreting overlap (standard IF practice). Because GCSAM is recorded in cytoplasm and at the cell membrane without a transmembrane segment, choose permeabilisation according to the antibody’s mapped epitope; an intracellular epitope requires access through the membrane (UniProt Q8N6F7 subcellular and topology; standard IF practice). No supplied GCSAM IF image or antibody-specific IF fixation and permeabilisation condition establishes a validated setting here (HPA subcellular; caption M12995-1).
What should I adjust when GCSAM staining is diffuse across the section?
First inspect a no-primary section and the distribution of precipitate; diffuse staining outside recognizable cells can indicate detection background rather than GCSAM localization (standard IHC practice). The selected tonsil caption reports primary and secondary dilutions of 1:200, with secondary incubation for 30 minutes at room temperature; use these as documented starting conditions for that image only (caption M12995-1). Check blocking, washing, endogenous peroxidase quenching, and chromogen development time as general chromogenic IHC controls (standard IHC practice). Compare intact germinal center cells with surrounding structures, since the HPA tissue profile describes cytoplasmic immune-cell staining and medium tonsil germinal center staining (HPA tissue IHC).
How should I quantify GCSAM staining across germinal centers? ⚠ ANSWER MARKED FOR VERIFICATION
Define germinal center regions from morphology before scoring and keep section thickness, retrieval, detection, and image exposure or scanning settings consistent across samples (standard IHC practice). Report the percentage of positive germinal center cells and an intensity-based H-score on a prespecified 0–300 scale, or report positive-cell density per mm² when region area is the relevant denominator (standard IHC practice). Normalize cell counts to all evaluable cells in the annotated compartment, or density to measured germinal center area, and exclude folds, edges, and necrotic areas (standard IHC practice). State thresholds and blinded scoring rules, since HPA reports medium germinal center staining but low consistency between antibody staining and RNA data (HPA tissue IHC).
How do I distinguish convincing GCSAM staining from tissue artefact?
A convincing result localizes to intact germinal center cells with chiefly cytoplasmic signal, consistent with the reported normal germinal center expression and tissue IHC profile (UniProt Q8N6F7 tissue specificity; HPA tissue IHC). Scrutinize signal confined to section edges, folds, or necrosis, and staining reproduced in a no-primary or peroxidase-control section, because these patterns can arise from processing or detection artefacts (standard IHC practice). Predominantly nuclear or widespread noncellular precipitate does not fit the recorded cytoplasmic and cell-membrane locations and warrants reassessment (UniProt Q8N6F7 subcellular; standard IHC practice). Interpret unexpected positive cell populations cautiously because HPA rates its tissue IHC approved while reporting low consistency with RNA expression (HPA tissue IHC).
Boster reagents
Best GCSAM / Germinal center-associated signaling and motility protein IHC Antibodies
Two human-reactive anti-GCSAM antibodies have IHC images from paraffin-embedded tissue and are listed for IF/ICC; no IF images are supplied (catalog: reactivity, applications, image captions, IF image alts).
Real IHC data
Anti-GCET2 Rabbit Monoclonal Antibody
Cat # M12995-1
Real IHC data
Anti-GCET2 Monoclonal Antibody
Cat # M12995
M12995-1 is listed for human IHC and IF/ICC, with an IHC image from paraffin-embedded human tonsil (catalog: applications, reactivity, IHC caption). M12995 has the same listed applications and human reactivity, with an IHC image from paraffin-embedded human bladder cancer (catalog: applications, reactivity, IHC caption).
Which to pick: For tissue IHC, M12995-1 offers the more detailed starting point: its paraffin-embedded human tonsil caption reports primary antibody at 1:200 and EDTA pH 9.0 retrieval; the fixative is unreported (M12995-1 IHC caption). For IF/ICC, either rabbit monoclonal is listed for human samples, though neither has a supplied IF image; M12995 also has a paraffin-embedded human bladder cancer IHC image with fixative unreported (catalog: host, applications, reactivity, IF image alts; M12995 IHC caption). Neither SKU has stated cross-species reactivity (catalog: both list human reactivity only).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q8N6F7 (GCSAM_HUMAN, Germinal center-associated signaling and motility protein).
- Human Protein Atlas. GCSAM tissue IHC expression (reliability: Approved).
- Human Protein Atlas. GCSAM subcellular location (ICC-IF): Highest expression in REH: 11.1 nTPM.
- Human Protein Atlas. GCSAM antibody validation summary (1 antibodies).
- Molecular and clinical analyses of PHF6 mutant myeloid neoplasia provide their pathogenesis and therapeutic targeting. Nature communications 2024 — PMC10901781.
- Latent Epstein-Barr virus infection collaborates with Myc over-expression in normal human B cells to induce Burkitt-like Lymphomas in mice. PLoS pathogens 2024 — PMC11045125.
- PubMed PMID:12819018 — UniProt-cited evidence.
- PubMed PMID:12509382 — UniProt-cited evidence.
- PubMed PMID:16641997 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for GCSAM (Germinal center-associated signaling and motility protein). Expected localisation Cytoplasm in tissue immune cells (HPA tissue IHC). Antigen retrieval: EDTA pH 9.0 HIER, heat-mediated (datasheet M12995-1). Validated IHC antibody: M12995-1 at 1:100-1:300 (the product's own IHC validation image is shown). Controls (HPA): positive Cerebellum (Cells in molecular layer); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human tonsil tissue; fixative not specified (datasheet M12995-1); 2. Fixation: Image fixative and duration unreported (datasheet M12995-1); 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 9.0 , 20min (datasheet M12995-1); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% normal serum of the secondary host, 30 min , room temperature (standard); 8. Primary antibody: Rabbit anti-GCSAM, 1:100-1:300 (datasheet M12995-1); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific); Caveat: Antibody staining and RNA expression show low consistency (HPA tissue IHC); Isoform / epitope: 3 isoforms; no transmembrane segment; epitope impact unknown (UniProt); Regulation: GC enriched; IL6 alters localisation (UniProt). Evidence: UniProt Q8N6F7, HPA tissue IHC · Approved, HPA cell-line RNA · Highest expression in REH: 11.1 nTPM, Datasheet M12995-1, PMC10901781. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/GCSAM/immunohistochemistry-ihc-guide.