Study of the cell proliferation index (Ki67) in inflammatory odontogenic cysts

Introduction

Inflammatory odontogenic cysts are lesions that develop from the cellular remains of odontogenesis. They are lesions that may recur after incomplete surgical enucleation with a variable clinical appearance depending on the clinical form. These clinical variations could be explained by the biological behaviour of the lesion cells which can be explored by the study of the cell proliferation index (Ki67). This justifies the initiation of this work whose objective was to study the level of expression of Ki67 and to measure the index of proliferation in odontogenic inflammatory cysts.

Material and method

This was a cross-sectional study with an analytical aim on surgical parts of odontogenic inflammatory cysts over a period of 31 months in the odontostomatology department of the Hôpital Général Idrissa Pouye. The Ki67 immunohistochemistry study was performed on 3μ thick histological sections of paraffin-fixed tissue. The inclusion criteria were any surgical specimen of odontogenic inflammatory cyst that we could collect. The variables studied were sociodemographic, clinical and histopathological.

Results

Radiculo-dental cysts represented 80.5% of the surgical specimens collected and residual cysts 12.2%. The percentage of Ki67-labelled cells was greater than 15% in 80.5% of the odontogenic inflammatory cysts and less than 7% in 19.5% of the cases. In addition, intense labelling was noted in radiculo-dental cysts and weak labelling in the other clinical forms of inflammatory odontogenic cysts obtained. An association was noted between the percentage of Ki67 labelled cells and histological types (p-value <0.001); but also between the intensity of Ki67 labelling and histological types (p-value <0.001).

Conclusion

The cell proliferation index (Ki67) could be used as a prognostic biomarker in odontogenic inflammatory cysts.