Profiles of cytokine expression in radicular cyst-lining epithelium examined by RT-PCR.

Levels of messenger RNA (mRNA) extracted from five samples of radicular cyst-lining epithelium were analyzed for cytokines, growth factors and epithelial cell growth-related receptors by RT-PCR. All five samples expressed IL-1alpha, -1beta, IL-6, IL-8, IL-11, TGF-beta1, PDGF-A and aFGF, and receptors for EGF (c-erbB), KGF, HGF (c-met) and IL-6. Some of the specimens expressed MIP-1alpha, RANTES, GM-CSF, M-CSF, TNF-alpha, PDGF-B and bFGF, but no expression of IL-2, IL-4, IFN-gamma, IGF-I, EGF and KGF was detected. These results indicate that radicular cyst-lining epithelium, which is considered to be identical to the cell rests of Malassez, may play a role in periodontal pocket formation or apical cyst formation by interaction with surrounding connective tissue or hematopoietic cells through the expression of various cytokines.