In an attempt to contribute to a better understanding about the growth of odontogenic lesions and the role of matrix metalloproteinases (MMPs) in this event, the immunoexpression of MMP-1, -2 and -9 was evaluated in 15 radicular cysts (RCs), 10 residual radicular cysts (RRCs), 10 dentigerous cysts (DCs) and 10 odontogenic keratocysts (OKs). To the analysis of epithelium and supporting mesenchyme, the following scores were utilized: negative (-), focal (+) and diffuse (++). Our results showed that the epithelial lining of the RRCs (100%) and DCs (70%) was diffuse to MMP-1, while to the RCs (53%) and OKs (60%) was predominantly focal. MMP-2 immunoscores ranged from focal in the lining of OKs (100%) and RCs (60%) to diffuse in RRCs (60%) and DCs (60%). With relation to MMP-9, the lining of all lesions was immunoexpressed focally (100% of RCs, RRCs and OKs and 60% of DCs). In relation to mesenchyme, the immunoexpression was higher in all OKs: the MMP-1 scores were diffuse (100%), while most of the other studied lesions were focal; all OKs focally immunoexpressed the MMP-2, what differed from the other cysts which did not express this MMP. To MMP-9, the mesenchyme of the OKs were immunoscored as focal (50%) and diffuse (50%), while most of other cysts had not shown staining. These results suggest that the growth of the odontogenic cysts may be influenced by the secreted MMPs. The most exuberant expression of the MMPs in mesenchyme of the OKs confirms its active participation in the growth, what may in part justify its bigger aggressiveness in comparison to other cystic lesions.
Odontogenic cysts; Metalloproteinases; Immunohistochemistry
