P63

Identifies a homologue of the p53 gene that is essential for normal breast and prostate development. p63 is expressed in myoepithelial cells, squamous and transitional epithelial cells, and in the basal layer of prostate and other epithelial tissues. Unlike other myoepithelial and basal cell markers, p63 immunoreactivity is localized to the nucleus. Detection of p63, or its absence, is useful for identifying invasive carcinoma in breast and prostate, as well as for the diagnosis of squamous and transitional cell carcinomas.