p40 (Squamous, Basal & Myoepithelial Cell Marker) [P40/4396R]



p40 antibody (antibody recognizing Np63 only) is an isoform of p63, is thought to function as a stem cell factor, responsible for maintaining cells in an uncommitted state with regenerative potential a role that may be recapitulated in tumors derived from these cells. p40 is normally expressed in the basal or progenitor cell layer of stratified epithelia (eg. squamous, urothelial, bronchial), basal cells of some glandular epithelia (eg. prostate), as well as myoepithelial cells of breast and salivary glands, trophoblasts and thymic epithelial cells. In tumor tissues, p40 expression is specific for squamous cell carcinoma. p40 is equivalent to p63 in sensitivity for lung squamous cell carcinoma, but it is markedly superior to p63 in specificity, which eliminates a potential pitfall of misinterpreting a p63-positive adenocarcinoma or unsuspected lymphoma as squamous cell carcinoma. p40 appears to be a more reliable marker for squamous cell carcinoma.

Product Properties & Targets

Species Reactivity
Cellular Localization
Gene Name
Mol. Weight of Antigen
Recombinant fragment (around aa1-100) of human p40 protein (exact sequence is proprietary)

Database Links

Entrez Gene ID

Additional Information

Human Gene Symbol
Chromosome Location

Known Applications & Suggested Dilutions

  • ELISA (For coating, order antibody without BSA)
  • Flow Cytometry (1-2ug/million cells)
  • ,Immunohistochemistry (Formalin-fixed) (1-2ug/ml for 30 minutes at RT),(Staining of formalin-fixed tissues requires heating tissue sections in 10mM Tris with 1mM EDTA, pH 9.0, for 45 min at 95 &degC followed by cooling at RT for 20 minutes),Optimal dilution for a specific application should be determined.

Key References

  • Signoretti S, et al. p63 is a prostate basal cell marker and is required for prostate development. Am J Pathol. 2000; 157(6):1769-75.
  • Terry J, et al. Optimal immunohistochemical markers for distinguishing lung adenocarcinomas from squamous cell carcinomas in small tumor samples. Am J Surg Pathol. 2010; 34(12):1805-11.

Storage & Stability

Antibody with azide - store at 2 to 8 °C. Antibody without azide - store at -20 to -80 °C. Antibody is stable for 24 months. Non-hazardous. No MSDS required.


This antibody is available for research use only and is not approved for use in diagnosis.

Supplied as

200ug/ml of Ab purified by Protein A Column. Prepared in 10mM PBS with 0.05% BSA & 0.05% azide. Also available WITHOUT BSA & azide at 1.0mg/ml.


There are no warranties, expressed or implied, which extend beyond this description. Company is not liable for any personal injury or economic loss resulting from this product.

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