Immunohistochemical Expression of PCNA in Epithelial Linings of Selected Odontogenic Lesions

Aim: Though odontogenic lesions have in common origin from the primitive odontogenic epithelium , there is a diversity in their initiation behavior and growth. The aggressive nature of odontogenic keratocyst similar to ameloblastoma in comparision with the other common odontogenic (dentigerous and radicular) cyst could be due to possible differences in their epithelial linings. PCNA (Proliferating cell nuclear antigen) is a cell cycle related antigen, used in the study of cell kinetics of these epithelial linings, to corelate the biological behaviour among these common odontogenic lesions. Objectives: This paper has intended to study the cell kinetics of 4 selected odontogenic lesions (dentigerous cyst, radicular cyst,odontogenic keratocyst and ameloblastoma) to demonstrate differences in their epithelial linings. Material and Methods: Sixty samples of paraffin embedded tissue specimens (archival tissues) were included (15 radicularcysts, 15 odontogenic keratocysts; 15 dentigerous cysts and15 Ameloblastoma. Results: Among cyst OKC had higher values than DC and RC. When staining results of all the cyst were compared individually with ameloblastoma ,the staining results of OKC was similar to ameloblastoma ,and ameloblastoma presented higher values than OKC (p=0.000). Conclusion: The results of this study show 1) Though OKC and DC are developmental in origin and radicular cyst is inflammatory, OKC has intrinsic growth potential among these cyst 2). Ameloblastoma has similar proliferative potential as OKC and hence it has been reinforced as KCOT(Keratocystic odontogenic tumour) in the recent classification.