Thermo Fisher Scientific p21 Recombinant Rabbit Monoclonal Antibody (ZR288), RAbMono

Applications and Tested Dilution

• Immunohistochemistry (Paraffin) (IHC (P)): 1:100–1:200

Product Specifications

Product Specific Information

A recommended positive control tissue for this product is Colon adenocarcinoma, though other tissue types may also be used.
This antibody is intended for laboratory professional use in detecting the corresponding protein in formalin-fixed, paraffin-embedded tissue during manual qualitative IHC testing. It should be used after a primary tumor diagnosis has been made by conventional histopathology.

This monoclonal antibody recognizes a 21 kDa p21WAF1 tumor suppressor protein, showing high specificity with no cross-reaction to other mitotic inhibitors. p21WAF1 acts as a cell cycle inhibitor during the G1 phase, regulated by p53. Expression is induced by wild-type p53 but not by mutant forms. Normal cells show strong nuclear p21 expression, while loss of p21 expression is observed in various carcinomas (e.g., gastric, non-small cell lung, thyroid).

For optimal staining, use on formalin-fixed, paraffin-embedded sections with heat-induced or enzymatic epitope retrieval.
IHC staining visualizes antigens through sequential antibody binding, enzyme complex formation, and chromogenic substrate reaction, producing a visible signal under a light microscope.

Control Recommendations

• Positive control: Colon adenocarcinoma or other verified tissues.
• External positive controls: Fresh, properly fixed and processed specimens with known low-level positive staining, ideal for detecting subtle reagent or method changes.
• Negative controls: Internal or external tissues without specific staining to confirm absence of non-specific background.

Target Information

Protein p21 is a tumor suppressor and CDK inhibitor, transcriptionally activated by p53. It regulates the cell cycle by inhibiting Cdk1 and Cdk2, blocking G1/S and G2/M transitions after DNA damage to allow repair. In the cytoplasm, p21 exhibits anti-apoptotic effects by inhibiting caspase 3, ASK1, and JNK. It plays dual roles in cancer, acting as both a tumor suppressor and oncogene depending on context.

For Research Use Only. Not for use in diagnostic procedures. Not for resale without express authorization.