CDKN2A / p16INK4a Antibodies, Nanobodies & Recombinant Proteins

p16 IHC — Cervical Cancer Diagnostics — p16INK4a immunohistochemistry is the standard-of-care ancillary test for diagnosing high-grade cervical intraepithelial neoplasia (CIN 2/3). Diffuse, strong nuclear and cytoplasmic staining ("block-positive" pattern) is a reliable surrogate marker for high-risk HPV E7 oncoprotein activity. The LAST Project and WHO Classification recommend p16 IHC as the primary adjunctive marker for distinguishing CIN 2 from mimics. For FFPE IHC, use HW820014 (full-length immunogen).
→ IHC Staining Protocol Guide

p16 IHC — Head & Neck Squamous Cell Carcinoma — In oropharyngeal SCC, p16 positivity serves as a surrogate for HPV-driven tumors. HPV-positive OPSCC has significantly better prognosis and different treatment implications. The 8th edition AJCC staging system uses p16 status to define a separate staging classification for oropharyngeal cancers.
→ Head & Neck SCC Research Reagents

CDKN2A in Melanoma & Familial Cancer — Germline CDKN2A mutations are the most common genetic cause of familial melanoma, accounting for 20–40% of hereditary melanoma kindreds. CDKN2A deletions and promoter hypermethylation are also frequent somatic events in non-small cell lung cancer, pancreatic adenocarcinoma, and glioblastoma.
→ Melanoma Research Reagents

p16 as a Cellular Senescence Marker — p16INK4a accumulates in senescent cells and is widely used as a biomarker of cellular senescence in aging research. Increased p16 expression is documented in aged tissues across multiple organs in both mouse and human studies. For mouse senescence models, use MW820014 (mouse-specific). Pair with SA-β-galactosidase and p21/γH2AX for a robust senescence confirmation panel.
→ Western Blot Protocol Guide

CDK4/6 Inhibitor Mechanism & Biomarker — CDK4/6 inhibitors (palbociclib, ribociclib, abemaciclib) mimic p16INK4a's natural function. Tumors with CDKN2A loss rely entirely on CDK4/6 for proliferation, making them strong candidates for CDK4/6 inhibitor therapy. CDKN2A status is increasingly evaluated as a predictive biomarker for CDK4/6 inhibitor response in breast cancer and NSCLC.
→ Browse CDK4 antibodies & proteins

What is the difference between CDKN2A and p16INK4a?
CDKN2A is the gene; p16INK4a is one of two proteins it encodes (the other being p14ARF). They share exons 2 and 3 but use different first exons read in alternative reading frames, producing entirely unrelated amino acid sequences. When selecting antibodies, check whether the immunogen targets the p16INK4a-specific region (exon 1α) or a shared region.

Which p16 antibody is best for IHC on FFPE tissue?
Choose an antibody raised against the full-length p16INK4a protein (Met1–Asp156) to maximize epitope recovery after antigen retrieval. HW820014 uses full-length human p16INK4a as the immunogen and is validated for IHC. Use HIER at pH 6.0 (citrate) or pH 9.0 (EDTA) for optimal results.

What does "block-positive" p16 staining mean?
Block-positive refers to continuous, diffuse, strong nuclear and cytoplasmic staining in the basal and parabasal layers. This pattern indicates functional Rb inactivation by HPV E7 and is the defining IHC criterion for HPV-driven HSIL (CIN 2–3). Patchy, focal, or cytoplasm-only staining is NOT block-positive.

Can p16 be used as a senescence marker in mouse models?
Yes. Use a mouse-reactive antibody such as MW820014 for WB on mouse tissue lysates or IHC on mouse tissue sections. Pair with SA-β-galactosidase, p21, and γH2AX for a robust senescence panel. Mouse p16 shares only ~60% sequence identity with human p16 — always use a species-matched antibody.

What is the role of CDKN2A in CDK4/6 inhibitor therapy?
CDK4/6 inhibitors (palbociclib, ribociclib, abemaciclib) mimic p16INK4a's function. Tumors with CDKN2A loss rely entirely on CDK4/6 for proliferation, making them candidates for CDK4/6 inhibitor therapy. Tumors with intact p16 expression may be intrinsically resistant. CDKN2A status is increasingly evaluated as a predictive biomarker for CDK4/6 inhibitor response.

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