Analysis of the neoplastic nature and biological potential of sporadic and nevoid basal cell carcinoma syndrome-associated keratocystic odontogenic tumor

Background: Keratocystic odontogenic tumor (KCOT), also known as odontogenic keratocyst, is a benign cystic neoplasm, which may be associated with nevoid basal cell carcinoma syndrome (NBCCS) and if it does, will occur as multiple cystic lesions. KCOT is locally destructive despite its bland histological features. However, the neoplastic nature of KCOT is not well established. Heparanase is an endo‐d‐glucuronidase enzyme that specifically cleaves heparan sulfate (HS) and the increase of its level in tumors promotes invasion, angiogenesis, and metastasis. Methods: To investigate the neoplastic character of KCOT, we studied the localization patterns of heparanase in KCOT, focusing on the differences between sporadic and NBCCS‐associated KCOTs, by immunohistochemistry and in situ hybridization. To compare the expression pattern of these cysts with non‐tumorous odontogenic developmental cyst, dentigerous cyst was included. Results: All the odontogenic cysts showed positive immunoreaction for heparanase protein in various intensities. The expression pattern of heparanase gene corresponded to that of protein expression. Interestingly, intense gene and protein expressions were observed in KCOT associated with NBCCS compared with sporadic ones and dentigerous cyst. Conclusions: The results implied that heparanase expression may be correlated with the neoplastic properties of KCOT, particularly in NBCCS‐associated cases.