Comparative analysis of the immunohistochemical expression of collagen IV, MMP-9, and TIMP-2 in odontogenic cysts and tumors

Objective The aim of this study was to evaluate the immunohistochemical expression of collagen IV, matrix metalloproteinase (MMP) 9 and tissue inhibitor of MMP (TIMP) 2 in dentigerous cysts (DCs), radicular cysts (RCs), keratocystic odontogenic tumors (KOTs), and ameloblastomas. Study design Twenty cases of DCs, 20 RCs, 20 KOTs, and 20 ameloblastomas were selected and analyzed by immunohistochemistry. Results Most DCs and RCs showed continuous and >50% staining for collagen IV in the basement membrane of the epithelium, whereas predominantly discontinuous thin and ≤50% staining was observed in KOTs and ameloblastomas, with a significant difference in staining percentage ( P < .001). MMP-9 was diffusely distributed and localized in both epithelial and mesenchymal cells of all of the lesions analyzed. The staining percentage was higher in the epithelium ( P = .058) and mesenchyme ( P = .005) of KOTs and ameloblastomas. Moreover, the distribution pattern, location, and percentage of expression of TIMP-2 were similar in the lesions studied, except for ameloblastoma, with a significant difference in staining percentage ( P < .001). Conclusion These results demonstrate that the interaction between collagen IV, MMP-9, and TIMP-2 is an important factor for the establishment of differences in the biologic behavior of the odontogenic cysts and tumors studied.