Expression of bone resorption regulators (RANK, RANKL, and OPG) in odontogenic tumors.

Objective: To investigate the expression of bone resorption regulators (receptor activator of nuclear factor kappa B [RANK], RANK ligand [RANKL], and osteoprotegerin [OPG]) in calcifying cystic odontogenic tumor (CCOT), adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor (CEOT), odontogenic myxoma (OM), and ameloblastic fibroma (AF).
Study Design: The expression of these mediators was evaluated by means of immunohistochemistry.
Results: All specimens demonstrated positive immunoreactivity to RANK, RANKL, and OPG. The quantification of these mediators in epithelium revealed a similar pattern of expression for RANKL and OPG in CCOT, AOT, CEOT, and AF. With regard to stromal/mesenchymal cells, the majority of AOT and CCOT cases showed a higher content of OPG than RANKL, whereas CEOT, OM, and especially AF had a tendency to present a greater content of RANKL than OPG.
Conclusion: Our data indicate that the CCOT, AOT, CEOT, OM, and AF cell constituents express key regulators of bone metabolism that might locally modulate tumor-associated bone resorption.