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RPA2 / Replication protein A 32 kDa subunit · IHC design guide
Design Immunohistochemistry for RPA2
Plan chromogenic paraffin-section RPA2 staining around its ubiquitous nuclear tissue pattern (HPA tissue IHC). This guide provides a catalog-antibody starting concentration of 2 µg/mL (datasheet M02067-2) and a scoring consideration for DNA damage-associated nuclear foci (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
RPA2 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 (HPA tissue IHC) | |
| Staining pattern | Widespread nuclear staining across cell types (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet M02067-2) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | None in HPA (detected in all 45 tissues); use no-primary + isotype controls |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep paraffin-section fixation consistent (standard IHC practice; not target-specific) | |
| Caveat | DNA damage can shift nuclear signal into foci (UniProt) | |
| Regulation | Expression regulation is unreported (UniProt) | |
| Isoform / epitope | 3 isoforms; epitope coverage is unspecified (UniProt) |
Section 1
Recommended RPA2 IHC & IF Protocols
Compare the catalog antibody’s IHC-P protocol (datasheet: M02067-2) with four published tissue protocols for RPA2 or phosphorylated RPA2 (PMC9743555; PMC5354728; PMC4344740; PMC10063624).
| Sample | Paraffin-embedded human spleen tissue; fixative not specified (datasheet M02067-2) |
| Fixation | Image fixative and duration unreported (datasheet M02067-2); 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 M02067-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet M02067-2) |
| Primary antibody | Mouse monoclonal (clone 3B2E9) anti-RPA2, 2 μg/ml (datasheet M02067-2) |
| Primary incubation | Overnight at 4 °C (datasheet M02067-2) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet M02067-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | RPA2-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Ubiquitous nuclear expression. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 for the catalog antibody (datasheet: M02067-2). The published protocols use different retrieval conditions (PMC9743555; PMC5354728; PMC4344740; PMC10063624).
Section 2
What Is the Expected RPA2 Staining Pattern?
RPA2 should appear primarily in nuclei across many cell types in paraffin tissue sections: HPA describes ubiquitous nuclear expression with supported IHC reliability (HPA tissue IHC). Nuclear staining fits its nuclear location and lack of a transmembrane segment (UniProt P15927). HPA reports high staining in selected cell populations, including bone marrow hematopoietic cells, breast glandular cells and bronchial respiratory epithelial cells (HPA tissue IHC).
| Nuclei stain in the expected tissue cell population, with little staining outside nuclei. | This matches the reported ubiquitous nuclear profile (HPA tissue IHC) and nuclear localisation (UniProt P15927). Compare the relevant cell population with its HPA entry; a high rating for one population does not set an intensity threshold for every nucleus. |
| The strongest apparent signal is cytoplasmic, membranous or extracellular. | That distribution conflicts with the reported nuclear pattern (HPA tissue IHC; UniProt P15927). Treat it as possible nonspecific staining or detection artefact, and assess whether a nuclear component remains distinguishable. |
| Signal appears mainly in a cell population other than the one selected as the expected positive control. | Check the tissue and cell annotation before calling cross-reactivity: HPA reports broad nuclear expression, while its listed high levels refer to particular populations (HPA tissue IHC). A discordant pattern may reflect nonspecific binding or endogenous detection activity (general IHC practice). |
| Colour spreads across tissue structures and obscures nuclear boundaries. | This is background rather than an interpretable nuclear pattern (HPA tissue IHC; general IHC practice). Review the negative control and detection reagents before assigning the colour to RPA2. |
| A known HPA high-staining cell population shows no nuclear signal. | The result conflicts with the reported positive pattern for that population (HPA tissue IHC). Check tissue identity, antibody performance and assay controls; this section has no target-specific evidence that fixation caused the loss. |
💡Expected RPA2 appearanceCall a result positive when nuclei are clearly stained in the relevant cell population, with strong signal plausible in HPA-listed high populations; dominant cytoplasmic or diffuse colour is suspect (HPA tissue IHC; UniProt P15927).
| Tissue and cell selection | HPA rates hematopoietic cells in bone marrow, glandular cells in breast and respiratory epithelial cells in bronchus as High (HPA tissue IHC). These are documented comparison populations, while the overall profile is ubiquitous nuclear staining (HPA tissue IHC). |
| Nuclear foci | RPA2 can redistribute to discrete nuclear foci after DNA damage in an ATR-dependent manner (UniProt P15927). Their absence in an ordinary paraffin section does not by itself contradict the expected nuclear IHC pattern (HPA tissue IHC; UniProt P15927). |
| Antibody evidence | HPA lists IHC as Supported for HPA026306, HPA026309 and CAB016538 (HPA antibodies). That supports comparison with HPA tissue patterns, but does not establish that an unlisted antibody or every assay condition will reproduce them. |
| Isoforms and modification | UniProt lists three RPA2 isoforms and phosphorylated residues (UniProt P15927). The supplied sources do not locate an antibody epitope or show how isoforms or phosphorylation change this IHC stain; avoid assigning pattern differences to either. |
| IF/ICC Q&A | Where is RPA2 seen by IF/ICC? HPA reports enhanced nucleoplasm and nuclear-body localisation; its listed ICC images include A-431, U-251MG and U2OS (HPA subcellular). This is an IF/ICC observation, not an IHC intensity standard. |
| Fixation sensitivity | Target-specific effects of fixation or antigen retrieval on RPA2 staining are unreported in the supplied UniProt and HPA records. Use the assay's documented controls to assess a paraffin-section result (general IHC practice). |
| Situation | Likely cause | Next action |
|---|---|---|
| The positive-control section has no nuclear colour. | An assay step or antibody may have failed; HPA documents high staining in specified cell populations, but gives no RPA2-specific fixation explanation here (HPA tissue IHC). | Confirm that the chosen cell population matches its HPA annotation, then inspect reagent validity, retrieval, dilution, detection and counterstain against the assay controls (general IHC practice). |
| Staining is predominantly cytoplasmic or membranous. | This conflicts with the nuclear location (UniProt P15927; HPA tissue IHC). Nonspecific binding or detection background is possible (general IHC practice). | Compare with a reagent-omission control and a documented HPA positive tissue; score RPA2 only where a convincing nuclear signal remains (HPA tissue IHC; general IHC practice). |
| Many tissue structures show uniform brown haze. | Diffuse colour can mask nuclear localisation and may arise from nonspecific staining or detection background (general IHC practice). | Review the negative control, blocking and detection steps; adjust the assay only against its controls, then reassess whether nuclei are distinct (general IHC practice). |
| Only an unexpected cell population appears strongly positive. | A cell-identity mismatch, nonspecific binding or endogenous detection activity may explain the result (general IHC practice). HPA's high ratings are cell-population specific (HPA tissue IHC). | Verify histology and the HPA cell annotation; compare the suspect population with control staining before treating it as RPA2-specific (HPA tissue IHC; general IHC practice). |
| The nuclear stain is present, but no discrete foci are visible. | Foci are reported after DNA damage (UniProt P15927); the HPA tissue IHC profile is ubiquitous nuclear staining and does not require visible foci (HPA tissue IHC). | Interpret the nuclear IHC result on its own merits. Reserve claims about damage-induced foci for an experiment designed to assess that response (UniProt P15927; general IHC practice). |
| Two antibodies yield different nuclear intensities. | HPA supports IHC staining for its listed antibodies, but the supplied record does not establish matched epitopes or identical intensities (HPA antibodies). | Check each antibody's own validation and assay controls, then compare compartment and cell population before comparing intensity (HPA antibodies; HPA tissue IHC; general IHC practice). |
Experiment evidence
IHC & IF images showing RPA2 staining
M02067-2 · IHCIHC analysis of RPA32/RPA2 using anti-RPA32/RPA2 antibody (M02067-2). RPA32/RPA2 was detected in a paraffin-embedded section of human spleen
M02067-2 · IHCIHC analysis of RPA32/RPA2 using anti-RPA32/RPA2 antibody (M02067-2). RPA32/RPA2 was detected in a paraffin-embedded section of human gastri
M02067-2 · IFIF analysis of RPA32/RPA2 using anti-RPA32/RPA2 antibody (M02067-2). RPA32/RPA2 was detected in an immunocytochemical section of Hela cells.
A02067-1 · IHCIHC analysis of RPA32/RPA2 using anti-RPA32/RPA2 antibody (A02067-1). RPA32/RPA2 was detected in paraffin-embedded section of human mammary
A02067-1 · IHCIHC analysis of RPA32/RPA2 using anti-RPA32/RPA2 antibody (A02067-1). RPA32/RPA2 was detected in paraffin-embedded section of human mammary
A02067-1 · IFIF analysis of RPA32/RPA2 using anti-RPA32/RPA2 antibody (A02067-1). RPA32/RPA2 was detected in immunocytochemical section of HELA cells. En
M02067-5 · IHCHuman kidney was stained with anti-RPA32/RPA2 rabbit antibody
M02067-5 · IHCHuman tonsil was stained with anti-RPA32/RPA2 rabbit antibody
A30447 · IHCImmunohistochemistry analysis of paraffin-embedded human lung carcinoma tissue, using RFA2 Antibody. The picture on the right is blocked wit
A30447 · IFImmunofluorescence analysis of HeLa cells, using RFA2 Antibody. The picture on the right is blocked with the synthesized peptide.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000117748-RPA2/tissue/cerebral+cortex#imid_4104608
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000117748-RPA2/tissue/colon#imid_4104542
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000117748-RPA2/tissue/liver#imid_4104535
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000117748-RPA2/tissue/kidney#imid_4104536
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB016538; green = RPA2, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB016538; green = RPA2, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for RPA2 IHC & IF
🧪Run bone marrow first and look for staining in hematopoietic cells (HPA: High in bone marrow hematopoietic cells). HPA detects RPA2 in all 45 scored tissues, so there is no supported negative tissue; use no-primary and isotype controls, and treat cells without detectable nuclear staining on the positive slide as background rather than proven RPA2-negative cells (HPA: no negative tissue rows; UniProt P15927: nuclear localization).
Positive control tissue: Adrenal gland (Glandular cells, HPA High)
Negative control tissue: None in HPA: RPA2 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show RPA2 in A-431, U-251MG, U2OS, U2OS, siRNA 2 (10x), U2OS, siRNA 2 (40x), U2OS, scrambled (10x), U2OS, scrambled (40x), with annotated localisation: Nucleoplasm (enhanced), Nuclear bodies (enhanced) (HPA subcellular).
Technical controls: Include a secondary-only slide, an IgG control matched to the primary antibody’s host species and isotype, and a processing-matched RPA2 knockout sample if available (standard IHC practice). In bone marrow, quench endogenous peroxidase before DAB detection and block endogenous biotin when using the caption’s streptavidin–biotin system (standard IHC practice; selected-SKU caption: SABC/DAB).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected-SKU paraffin-section caption does not state a fixative (selected-SKU caption: fixative unreported). Heat retrieval in EDTA at pH 8.0 is documented for spleen IHC, but the evidence does not establish that retrieval is required or that frozen sections are easier (selected-SKU caption: EDTA retrieval in paraffin-embedded spleen). ICC-IF images show nucleoplasmic and nuclear-body localization, but no matched evidence establishes that IF is easier than IHC; bone marrow’s endogenous peroxidase warrants attention with DAB detection (HPA: nucleoplasm and nuclear bodies; standard IHC practice).
HPA tissue IHC evidence for RPA2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — High 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 |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Appendix | Endocrine cells | High | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Breast | Glandular cells | High | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: RPA2 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced RPA2 IHC Tips
Use the catalog antibody’s paraffin-section result as the starting point, then judge staining against RPA2’s predominantly nuclear localisation (datasheet M02067-2; HPA subcellular).
How should I troubleshoot weak nuclear RPA2 staining after antigen retrieval?
Start with heat-mediated retrieval in EDTA at pH 8.0 for paraffin sections (datasheet M02067-2). The catalog antibody produced staining in a paraffin-embedded human spleen section using that retrieval, followed by 2 μg/ml primary antibody overnight at 4°C (datasheet M02067-2). If nuclei remain weak, compare retrieval duration on adjacent sections while keeping antibody concentration and detection constant, and inspect tissue integrity after heating (standard IHC practice). If staining is still weak, trial another retrieval buffer as a fallback on matched sections, with a no-primary control to reveal detection background (standard IHC practice). Score nuclear signal separately from diffuse cytoplasmic color because RPA2 is nuclear (UniProt P15927 subcellular).
Could fixation explain weak or uneven RPA2 staining in paraffin sections?
Target-specific fixation sensitivity is unknown: the selected paraffin-section caption does not state its fixative, and the supplied evidence does not compare fixation conditions (datasheet M02067-2). Record the fixative, time before fixation, and fixation duration for each specimen before comparing staining intensity (standard IHC practice). On matched sections, hold retrieval at EDTA pH 8.0 and the primary antibody at 2 μg/ml, as used for the catalog image (datasheet M02067-2). Check whether weak nuclei track processing batches or tissue preservation, then repeat a representative section with the same staining run and controls (standard IHC practice). Do not assign a fixation mechanism from RPA2 localisation or phosphorylation alone (UniProt P15927 subcellular; modified residues).
What should I make of cytoplasmic or punctate RPA2 staining?
Expect predominantly nuclear staining in tissue: HPA describes ubiquitous nuclear expression, and UniProt places RPA2 in the nucleus and PML bodies (HPA tissue IHC; UniProt P15927 subcellular). Nuclear puncta can be plausible because RPA2 redistributes to discrete nuclear foci after DNA damage in an ATR-dependent manner (UniProt P15927 subcellular). Compare puncta with a nuclear counterstain and intact cellular morphology; score diffuse cytoplasmic DAB separately rather than counting it as nuclear positivity (standard IHC practice). If cytoplasmic color dominates, inspect the no-primary control, section edges, and endogenous peroxidase blocking before attributing it to RPA2 (standard IHC practice). Its lack of a transmembrane segment gives no basis for interpreting membrane-restricted staining as expected (UniProt P15927 topology).
Can this stain distinguish RPA2 isoforms or phosphorylation states?
Do not score an isoform or phosphorylation state from this stain without epitope-specific validation: the record lists 3 isoforms and several modified residues, but the supplied caption gives no epitope mapping (UniProt P15927 isoforms; modified residues; datasheet M02067-2). RPA2 includes phosphorylation sites at residues 4, 8, 21, and 23 among its annotated modifications (UniProt P15927 modified residues). Compare staining with independently validated isoform-specific or modification-specific reagents if that distinction is essential, using matched sections and controls (standard IHC practice). Report the catalog antibody’s result as RPA2 immunoreactivity, and document retrieval and antibody concentration so differences across samples are interpretable (datasheet M02067-2; standard IHC practice).
How can I examine RPA2 and cell identity by IF alongside this IHC result?
For a separate IF assay, pair RPA2 with a validated marker of the expected cell type and a nuclear counterstain; HPA reports high staining in bone-marrow hematopoietic cells, among other cell types (HPA tissue IHC; standard IF practice). Choose spectrally separated fluorophores and place the weaker signal in a channel with low tissue autofluorescence, checking an unstained specimen first (standard IF practice). Because RPA2 is nuclear and has no transmembrane segment, optimise permeabilisation for access to its nuclear epitope while preserving morphology (UniProt P15927 subcellular; topology; standard IF practice). Use single-color controls to assess bleed-through, then compare nuclear overlap and puncta without transferring the paraffin-section antibody concentration directly into IF (standard IF practice; datasheet M02067-2).
How do I separate RPA2 signal from brown background in chromogenic IHC?
Run a no-primary control and inspect endogenous peroxidase activity, nonspecific secondary binding, and uneven DAB deposition before adjusting the primary antibody (standard IHC practice). The catalog paraffin-section result used 10% goat serum block, 2 μg/ml mouse primary overnight at 4°C, biotinylated goat anti-mouse secondary for 30 minutes at 37°C, and SABC with DAB (datasheet M02067-2). If controls show background, review peroxidase blocking and, for the biotin-based detection scheme, endogenous biotin controls (standard IHC practice; datasheet M02067-2). Compare nuclear staining away from folds, cut edges, and necrotic regions, since HPA describes RPA2 tissue expression as nuclear (standard IHC practice; HPA tissue IHC).
What is a defensible way to quantify RPA2 IHC across samples? ⚠ ANSWER MARKED FOR VERIFICATION
Define positive nuclei using the same chromogen threshold and counterstain criteria across all sections, and exclude folds, necrosis, and poorly preserved areas (standard IHC practice). Report the percentage of positive nuclei and, when intensity matters, an H-score calculated from the percentages at each prespecified nuclear intensity grade (standard IHC practice). For spatial comparisons, count positive nuclei per mm² of viable tissue and normalise to total evaluable nuclei or the relevant cell population, rather than section area alone (standard IHC practice). Stratify by cell type where morphology permits because HPA reports high staining in several distinct populations and a broadly nuclear tissue profile (HPA tissue IHC). Keep retrieval, detection, imaging, and scoring rules consistent across batches (standard IHC practice).
When is an apparent RPA2-positive nucleus convincing rather than artefactual?
A convincing result is nuclear signal in intact cells that exceeds the no-primary control and repeats across comparable sections (HPA tissue IHC; standard IHC practice). HPA describes ubiquitous nuclear expression, while UniProt also reports nuclear bodies and DNA-damage-associated nuclear foci; a punctate pattern therefore needs nuclear confirmation rather than automatic rejection (HPA tissue IHC; UniProt P15927 subcellular). Treat isolated edge staining, necrotic deposits, and staining confined to the wrong compartment as suspect until morphology and controls support them (standard IHC practice; UniProt P15927 subcellular). Check endogenous peroxidase and biotin-related signal where relevant to the catalog’s SABC/DAB method, and avoid interpreting intensity alone as proof of DNA damage (datasheet M02067-2; standard IHC practice; UniProt P15927 function).
Boster reagents
Best RPA2 / Replication protein A 32 kDa subunit IHC Antibodies
The catalog includes anti-RPA2 IHC images from human tissues and mouse and rat liver (catalog IHC captions), plus HeLa IF images for three human-reactive antibodies (catalog IF captions; catalog reactivity).
Real IHC data
Anti-RPA32/RPA2 Antibody ® (monoclonal, 3B2E9)
Cat # M02067-2
Real IHC data
Anti-RPA32/RPA2 Antibody ®
Cat # A02067-1
Real IHC data
Anti-RPA32/RPA2 Rabbit Monoclonal Antibody
Cat # M02067-5
Real IHC data
Anti-RFA2 Antibody
Cat # A30447
M02067-2 has a human spleen IHC image, and A02067-1 has a human mammary cancer IHC image (respective IHC captions). M02067-5 has human kidney, mouse liver and rat liver IHC images, while A30447 has a human lung carcinoma IHC image (respective IHC captions).
Which to pick: For paraffin-section IHC, choose M02067-2 for human spleen or A02067-1 for human mammary cancer; both captions document EDTA pH 8.0 retrieval and DAB detection, but neither reports the fixative (respective IHC captions). For IF/ICC, A02067-1 and M02067-2 both list those applications and show HeLa IF staining (catalog applications; respective IF captions). For IHC across human, mouse and rat samples, choose M02067-5, whose reactivity list covers all three species and whose IHC captions show human kidney and mouse and rat liver (catalog reactivity; M02067-5 IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P15927 (RFA2_HUMAN, Replication protein A 32 kDa subunit).
- Human Protein Atlas. RPA2 tissue IHC expression (reliability: Supported).
- Human Protein Atlas. RPA2 subcellular location (ICC-IF): Localized to the nucleoplasm and nuclear bodies..
- Human Protein Atlas. RPA2 antibody validation summary (3 antibodies).
- Markers associated with genomic instability, immunogenicity and immune therapy responsiveness in Metaplastic carcinoma of the breast: Expression of γH2AX, pRPA2, P53, PD-L1 and tumor infiltrating lymphocytes in 76 cases. BMC cancer 2022 — PMC9743555.
- S4S8-RPA phosphorylation as an indicator of cancer progression in oral squamous cell carcinomas. Oncotarget 2017 — PMC5354728.
- Identification of stroke-associated-antigens via screening of recombinant proteins from the human expression cDNA library (SEREX). Journal of translational medicine 2015 — PMC4344740.
- Unravelling the clinicopathological and functional significance of replication protein A (RPA) heterotrimeric complex in breast cancers. NPJ breast cancer 2023 — PMC10063624.
- PubMed PMID:2406247 — UniProt-cited evidence.
- PubMed PMID:16710414 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for RPA2 (Replication protein A 32 kDa subunit). Expected localisation Nuclear staining in tissue (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet M02067-2). Validated IHC antibody: M02067-2 at 2 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative None in HPA (detected in all 45 tissues); use no-primary + isotype controls. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human spleen tissue; fixative not specified (datasheet M02067-2); 2. Fixation: Image fixative and duration unreported (datasheet M02067-2); 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 M02067-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet M02067-2); 8. Primary antibody: Mouse monoclonal (clone 3B2E9) anti-RPA2, 2 μg/ml (datasheet M02067-2); 9. Primary incubation: Overnight at 4 °C (datasheet M02067-2). Watch for: Fixation: Keep paraffin-section fixation consistent (standard IHC practice; not target-specific); Caveat: DNA damage can shift nuclear signal into foci (UniProt); Isoform / epitope: 3 isoforms; epitope coverage is unspecified (UniProt); Regulation: Expression regulation is unreported (UniProt). Evidence: UniProt P15927, HPA tissue IHC · Supported, HPA ICC-IF · nucleoplasm and nuclear bodies., Datasheet M02067-2, PMC9743555, PMC5354728. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/RPA2/immunohistochemistry-ihc-guide.