Immunohistochemical Expression of CK13 and Molecular Analysis of KRT13 and APC in Odontogenic Ghost Cell Lesions, Adenoid Ameloblastoma, and Conventional Ameloblastoma

PURPOSE: The aim of this study was to evaluate the immunohistochemical expression of CK13 and specific mutations in KRT13 and APC genes in cases of calcifying odontogenic cyst (COC), dentinogenic ghost cell tumor (DGCT), adenoid ameloblastoma (AA), and conventional ameloblastoma (CA). MATERIALS AND METHODS: Twenty-nine cases (22 COC, 2 DGCT, 1 AA, and 4 CA) were collected from two diagnostic centers. Immunohistochemical analysis of CK13 expression and polymerase chain reaction (PCR)-based molecular investigation of specific mutations (APC E1080* and KRT13 M239V and Y281H) were performed. RESULTS: CK13 expression in COC was observed in the suprabasal/superficial layers of the cystic epithelium in 14 cases-64%; ghost cells showed positivity in 12 cases-54%. DGCT cases were negative in the epithelial proliferation but positive in ghost cells. The AA case was negative. Three CA cases demonstrated positivity in suprabasal/central cells. None of the cases harbored the investigated mutations. However, the intronic polymorphism KRT13 c.735 + 10A > G (dbSNP rs7211235) was identified in 16 COC cases, one DGCT case, one AA case, and one CA case, whereas KRT13 c.735 + 6C > T (dbSNP rs181122697) was detected in one COC case. Additionally, one case harbored a previously unreported silent/synonymous mutation, KRT13 c.690G > A (p.E230E), of unknown significance. CONCLUSIONS: CK13 expression in COC and CA suggests squamous differentiation of odontogenic epithelium. The detected KRT13 genetic variations are probably not associated with tumorigenic mechanisms in COC, DGCT, AA, and CA. The APC E1080* mutation was not identified in any of the entities included in the present study. Further studies are therefore required to more precisely define the genetic profile of these entities and, particularly, to clarify the potential biological relationship between dentinogenic ghost cell tumor and adenoid ameloblastoma.