Benign and malignant odontogenic neoplasms of the jaws show a concordant nondiscriminatory p63/p40 positive immunophenotype

Objectives: Antibody p40, which recognizes exclusively ΔNp63 but not TAp63, has shown diagnostic utility in salivary gland and sinonasal tract malignancies. Although p63 immunophenotypic characterization of odontogenic lesions has been reported, p40 expression has not been previously studied. We aimed to study p40 immunoreactivity in odontogenic tumors (OTs) and odontogenic cysts (OCs) and to investigate possible discriminatory properties of the combined p63/p40 immunoprofile in OTs and OCs. Study Design: Fourteen ameloblastomas, 7 adenomatoid odontogenic tumors, 6 calcifying epithelial odontogenic tumors, 1 squamous odontogenic tumor, 4 primary intraosseous odontogenic carcinomas, 5 calcifying odontogenic cysts, 4 glandular odontogenic cysts, 3 odontogenic keratocysts, 3 dentigerous cysts, and 1 each radicular and orthokeratinized cysts were stained for p63 (4A4) and p40 (BC28) antibodies. Results: Ameloblastoma, adenomatoid odontogenic tumor, calcifying epithelial odontogenic tumor, squamous odontogenic tumor, and primary intraosseous odontogenic carcinoma demonstrated concordant p63+/p40+ immunophenotype. P40, similar to p63, highlighted almost all lesional cells of OTs and, overall, the full thickness of the epithelial lining of the cystic areas of OCs and ameloblastoma. The keratin layer of OKC and the adluminal ductal and mucous cells of GOC were p63–/p40–. Conclusions: Both ΔNp63 and TAp63 isoforms are present in neoplastic and developmental odontogenic lesions; and p63/p40 immunophenotype is nondiscriminatory pertaining to benign and malignant OTs and OCs.