Oral Pathology: Gene Expression in Odontogenic Cysts
Odontogenic cysts are a group of common pathological lesions of the jaw. Typically, they can be found randomly on X-rays as round benign lesions. However, some of them can behave aggressively with a tendency toward malig-nancy. Among odontogenic cysts with benign pathology, up to 60% of all jaw cysts are radicular cysts, which originate from root canal infection. Pathogenesis involves the interaction between osteoblasts, osteocytes, and osteoclasts as well as the expression of RANK-RANKL/OPG signaling system. Furthermore, collagenases (e.g., MMPs) are expressed in epithelial lining of the cyst. Among odontogenic cysts with potentially aggressive behavior, odontogenic keratocysts (OKCs) have a high rate of recurrence and very debatable treatment options; they can be associated with Gorlin syndrome. Keratocysts have developmental origin and show variability in their gene expression profiles. Their etiology is closely related to genetic factors, especially mutations in different members of Shh signaling pathway, including PTCH gene. cells proliferate, the epithelial nest is formed. When the epithelial nest reaches the size of 1 cm, the center becomes necrotic leading to the formation of future cystic cavity, which becomes lined with the epithelium. For unknown reasons, this epithelium starts secreting fluid, which is called cystic fluid. These steps lead to the formation of radicular cyst, a round cavity filled with fluid and lined with the epithelium and fibrous connective tissue. This description of the radicular cyst development is the prevailing theory.