Test Catalog

Test ID: P63    
p63 Immunostain, Technical Component Only

Useful For Suggests clinical disorders or settings where the test may be helpful

Aiding in identifying squamous, urothelial, or myoepithelial differentiation in tumors

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

The p63 protein is a member of the p53 family of tumor-suppressor proteins. The predominant localization of p63 protein is in the basal layer of stratified squamous and transitional epithelia. p63 is negative in malignant tumors of the prostate. Striated muscle staining may be observed with p63.

Interpretation Provides information to assist in interpretation of the test results

This test does not include pathologist interpretation, only technical performance of the stain. If interpretation is required, order PATHC / Pathology Consultation for a full diagnostic evaluation or second opinion of the case.


The positive and negative controls are verified as showing appropriate immunoreactivity and documentation is retained at Mayo Clinic Rochester. If a control tissue is not included on the slide, a scanned image of the relevant quality control tissue is available upon request, call 855-516-8404.


Interpretation of this test should be performed in the context of the patient's clinical history and other diagnostic tests by a qualified pathologist.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Livasy CA, Karaca G, Nanda R, et al: Phenotypic evaluation of the basal-like subtype of invasive breast carcinoma. Mod Pathol. 2006;19:264-271

2. Ueo T, Kashima K, Daa T, Kondo Y, Sasaki A, Yokoyama S: Immunohistochemical analysis of morules in colonic neoplasma: morules are morphologically and qualitatively different from squamous metaplasia. Pathobiology. 2005;72(5):269-278

3. Varma M, Jasani B: Diagnostic utility of immunohistochemistry in morphologically difficult prostate cancer: review of current literature. Histopathology. 2005 Jul;47(1):1-16

4. Weinstein MH, Signoretti S, Loda M: Diagnostic utility of immunohistochemical staining for p63, a sensitive marker of prostatic basal cells. Mod Pathol. 2002 Dec;15(12):1302-1308