Background: Keratocystic odontogenic tumors are benign neoplasms of the viscerocranium that occur sporadically as well as in association with Gorlin-Goltz syndrome. Multiple basal cell carcinomas of the skin are another typical feature of Gorlin-Goltz syndrome. Aberrant activation of sonic hedgehog signaling has been reported for sporadic and hereditary basal cell carcinoma caused by specific genetic mutations, but for keratocystic odontogenic tumors, the role of aberrant sonic hedgehog signaling has not yet been evaluated in detail.
Materials and methods: In the present study, 131 keratocystic odontogenic tumors were analyzed by immunohistochemistry for the expression of sonic hedgehog signaling proteins SHH, PTCH1, SMO, GLI1, and NMYC on tissue microarray sections.
Results: High expression of the analyzed proteins-between 67.3% (PTCH1) and 92.9% (SHH)-was found in the epithelial compartment of the keratocystic odontogenic tumors analyzed. In the stromal compartment of the tumors, high expression of the target proteins was found significantly less frequently (all p-values <0.001).
Conclusion: Aberrant sonic hedgehog signaling is critically involved in the molecular pathogenesis of keratocystic odontogenic tumors. This finding underlines the neoplastic character of this intraosseous lesion. Because of high recurrence rates after local excision, more radical surgical approaches are recommended for treating keratocystic odontogenic tumors.