Overexpression of Fra-1, c-Jun and c-Fos in odontogenic keratocysts: potential correlation with proliferative and anti-apoptotic activity

Aims The purpose of this study was to explore the potential involvement of Fra-1, c-Jun and c-Fos, three vital members of the AP-1 complex, in the pathogenesis of odontogenic keratocysts (OKCs). Methods and results Tissue samples, containing 10 normal oral mucosa (OM), 10 dentigerous cysts (DC) and 32 OKC specimens, were applied to investigate the expression levels of Fra-1, c-Jun and c-Fos by immunohistochemistry and real-time-quantitative polymerase chain reaction (RT-qPCR). The association between Fra-1, c-Jun and c-Fos expression levels and markers of proliferation [Ki-67, proliferating cell nuclear antigen (PCNA)], anti-apoptosis (Bcl-2) was then investigated in the OKC serial tissue sections. The results showed that Fra-1, c-Jun and c-Fos expression levels were increased significantly in OKCs compared to these in OM and DC tissue samples. Meanwhile, the expression levels of Fra-1, c-Jun and c-Fos were associated positively with the expression levels of Ki-67, PCNA and Bcl-2, as confirmed further by double-labelling immunofluorescence analysis and hierarchical analysis. Conclusions This study revealed for the first time that Fra-1, c-Jun and c-Fos were overexpressed in OKCs and had a close correlation with proliferation and anti-apoptosis potential of OKCs.