• Nuclear p63 expression in pulmonary squamous cell carcinoma.
  • Nuclear p63 staining in basal cells of normal prostate.
  • Nuclear staining for p63 in myoepithelial cells of normal breast lobules.
  • p63 expression in basal cells of benign prostate.
  • Nuclear p63 expression in sarcomatoid squamous cell carcinoma. Basal cells of adjacent sebaceous gland are also positive.
  • Nuclear p63 expression in sarcomatoid squamous cell carcinoma.
  • Nuclear p63 expression in sarcomatoid squamous cell carcinoma. Overlying epidermis is also positive.
  • Nuclear p63 expression in sarcomatoid squamous cell carcinoma.



Technical InfoEdit

Staining PatternEdit

  • Nuclear

Expression in Normal TissuesEdit

  • Basal cells of respiratory epithelium[1]
  • Scattered germinal center cells[1]
  • Cytotrophoblasts in placenta[1]
  • Basal cells in prostate[1]
  • Myoepithelial breast cells

Expression in Neoplastic EntitiesEdit

Tumor name % Positive Staining (Sensitivity) Number of Cases Specificity Comments
Breast myoepithelioma

Intermediate/Uncertain Malignant PotentialEdit
Tumor name % Positive Staining (Sensitivity) Number of Cases Specificity Comments

Tumor name % Positive Staining (Sensitivity) Number of Cases Specificity Comments
Squamous cell carcinoma of lung (positive in 92%)[1]
Adenoid cystic carcinoma (without basilar growth)[3]
Urothelial carcinoma[4] 97%[4] 33/34[4]

  • Uncommonly, may be positive in melanoma
    • (2 out of 25 cases)[1]
    • (2 out of 59 cases)(but less than 30% of tumor cells stained in these 2 melanomas)[5]

Expression in Non-Neoplastic EntitiesEdit

Pertinent NegativesEdit

This antigen is typically NOT expressed by the following entities:

  • Most sarcomas
  • Invasive breast and prostatic adenocarcinomas
  • Collecting duct carcinoma of kidney [4]

Practical Uses / PanelsEdit

  • p63 is very useful for malignant cutaneous spindle cell tumors. Sarcomatoid squamous cell carcinomas are often negative for cytokeratins, but are typically positive for p63.
  • Good for identifying if invasive prostatic adenocarcinoma (vs. atrophy, high-grade PIN, etc.) is present.
  • p63 is useful in spindle areas when differentiating metaplastic carcinoma, phyllodes, fibromatosis and myofibroblastoma of the breast. The spindle area of metaplastic carcinoma is immunoreactive for p63 in contrast with the spindle cell areas of phyllodes, fibromatosis and myofibroblastoma which are nonreactive. [6]
  • p63 with PAX8 are useful as a panel in cases of poorly differentiated epithelial tumors of the renal medulla when the differential diagnosis includes collecting duct carcinoma (p63-, PAX8+) and urothelial carcinoma (p63+, PAX8-).

Common PitfallsEdit

Related Links/Other ResourcesEdit


  1. 1.0 1.1 1.2 1.3 1.4 1.5 Distribution of p63, cytokeratins 5/6 and cytokeratin 14 in 51 normal and 400 neoplastic human tissue samples using TARP-4 multi-tumor tissue microarray.VIRCHOWS ARCHIV. 2003. Volume 443, Number 2, 122-132.
  2. BarbareschiM, Pecciarini L, Cangi MG, Macri E, Rizzo A, Viale G, Doglioni C. p63, a p53 homologue, is a selective nuclear marker of myoepithelial cells in the human breast. Am J Surg Pathol. 2001;25(8):1054-60
  3. Mastropasqua MG, Maiorano E, Pruneri G, Orvieto E, Mazzarol G, Vento AR, Viale G. Immunoreactivity for c-kit and p63 as an adjunct in the diagnosis of adenoid cystic carcinoma of the breast. Mod Pathol. 2005;18(10):1277-82
  4. 4.0 4.1 4.2 4.3 PAX8 (+)/p63 (-) immunostaining pattern in renal collecting duct carcinoma (CDC): a useful immunoprofile in the differential diagnosis of CDC versus urothelial carcinoma of upper urinary tract. Am J Surg Pathol. 2010 Jul;34(7):965-9.
  5. Brinck U, et al. Comparative study of p63 and p53 expression in tissue microarrays of malignant melanomas. Int J Mol Med. 2002 Dec;10(6):707-11.
  6. [ Tse GM, Tan PH, Lui PC, Putti TC. Spindle cell lesions of the breast--the pathologic differential diagnosis. Breast Cancer Res Treat. 2008 May;109(2):199-207. Epub 2007 Jul 18.]

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