STUDY OF IMMUNOHISTOCHEMICAL EXPRESSION OF RANKL, OPG, IL-6, AND CTSK IN ODONTOGENIC CYSTS AND TUMORS

Abstract

Objective To evaluate the receptor activator of nuclear factor-K B ligand (RANKL), osteoprotegerin (OPG), interleukin-6 (IL-6), and cathepsin K (CTSK) antigens in 34 radicular cysts (RC), 28 odontogenic keratocysts (OKC), and 25 ameloblastomas (AM). Study Design The immunohistochemical expression of these proteins was evaluated considering the mean of percentage marked area in 10 consecutive fields (400 x), considering epithelial and connective tissue individually. The analysis of variance (ANOVA) test was used to compare the groups. A P value < .05 indicated statistically significant data. Results RANKL was statistically higher in CR and OKC compared with AM in epithelium and connective tissue. No statistical difference was found for the OPG between the groups. Statistical difference was noted to IL-6 between all groups only in connective tissue, decreasing from CR, to AM, and to OKC. CTSK was statistically higher in AM and OKC compared with CR. Conclusions In AM and OKC cases, the mechanism of bone resorption seems to be related to the CTSK pathway, whose expression was independent of the inflammatory component. To RC the mechanism of bone resorption is more related with RANKL and IL-6 proteins and dependent of an inflammatory component. To evaluate the receptor activator of nuclear factor-K B ligand (RANKL), osteoprotegerin (OPG), interleukin-6 (IL-6), and cathepsin K (CTSK) antigens in 34 radicular cysts (RC), 28 odontogenic keratocysts (OKC), and 25 ameloblastomas (AM). The immunohistochemical expression of these proteins was evaluated considering the mean of percentage marked area in 10 consecutive fields (400 x), considering epithelial and connective tissue individually. The analysis of variance (ANOVA) test was used to compare the groups. A P value < .05 indicated statistically significant data. RANKL was statistically higher in CR and OKC compared with AM in epithelium and connective tissue. No statistical difference was found for the OPG between the groups. Statistical difference was noted to IL-6 between all groups only in connective tissue, decreasing from CR, to AM, and to OKC. CTSK was statistically higher in AM and OKC compared with CR. In AM and OKC cases, the mechanism of bone resorption seems to be related to the CTSK pathway, whose expression was independent of the inflammatory component. To RC the mechanism of bone resorption is more related with RANKL and IL-6 proteins and dependent of an inflammatory component.