Comparative Immunohistochemical Analysis of p53 and Alpha-SMA in Ameloblastoma, AOT and OKC.

OBJECTIVES: Ameloblastoma is a benign but highly infiltrative tumour, a behaviour that is lacking in adenomatoid odontogenic tumour but partly shared by the odontogenic keratocyst which possesses a unique intrinsic growth potential with marked ability for destroying bone and a high tendency recurrence. High frequency of stromal myofibroblasts (assessed with alpha smooth muscle actin (α-SMA) correlates with aggressive behaviour while p53-cell cycle regulation system is critical in odontogenic tumours with immunoreactivity signifying prognostic status. This study aims to determine and compare the immunoreactivity of these selected tumours to p53 and α-SMA in order to establish if a relationship exists between the frequency and pattern of distribution of myofibroblasts and the behaviour of these lesions. MATERIALS AND METHODS: 69 blocks of ameloblastoma, and 23 each of adenomatoid odontogenic tumor (AOT), and odontogenic keratocyst (OKC/KCOT) were retrieved. Immunohistochemistry technique was applied for evaluation of these two markers staining with primary antibodies to p53 and -SMA and the frequency and pattern of distribution of myofibroblasts and immunoreactivity to p53 analysed and compared using ANOVA. p was set at <0.05. RESULTS AND CONCLUSION: Immunoreactivity to p53 and α-SMA was highest in ameloblastoma (solid compared to unicystic) with highest mean positive cells to α-SMA (29.7±20.1) and p53 (28.3±24.5) in plexiform ameloblastoma. This suggests that ameloblastoma was the most aggressive of tumours studied. Different pharmacological agents that can regulate stromal MF are useful aids to decrease the need for radical surgery in extensive and aggressive odontogenic tumours.

ABSTRAIT OBJECTIFS: L'améloblastome est bénin mais untumeur mes infiltratif, un comportement qui fait défaut dans la tumeur odontogénique adénomatoïde mais en partie partagé par le kératocyste odontogène qui possède un potentiel de croissance intrinsèque unique avec une capacité marquée de destructionet une récidive à forte tendance. Haute fréquence de stromalmyofibroblastes (évalués avec de l'actine musculaire alpha lisse (α-SMA) est en corrélation avec un comportement agressif lors de la régulation du cycle des cellules p53 est essentiel dans les tumeurs odontogènes immunoréactives signifiant le statut pronostique. Cette étude vise à déterminer et comparer activité l'immunoré de ces tumeurs sélectionnées à p53 et α-SMA afin d'établir s'il existe une relation entre le fréquence et schéma de distribution des myofibroblastes et de la comportement de ces lésions. MATÉRIAUX ET MÉTHODES: 69 blocs d'améloblastome, et 23 chacun de tumeur odontogénique adénomatoïde (AOT) et odontogènedes kératocystes (OKC/KCOT) ont été récupérés. Immunohistochimiela technique a été appliquée pour l'évaluation de ces deux marqueurs de coloration avec des anticorps primaires dirigés contre p53 et α-SMA et la fréquence et schéma de distribution des myofibroblastes et de l'immunoréactivité àp53 analysé et comparé à l'aide de l'ANOVA. p a été fixé à <0,05. RÉSULTATS ET CONCLUSION: Immuno réactivité à p53 et α-SMA était la plus élevée dans l'améloblastome (solide par rapport α-SMA (29,7±20,1) et p53(28,3±24,5) dans l'améloblastome plexiforme. Cela suggère que L'améloblastome était la tumeur la plus agressive étudiée. Les agents pharmacologiques différentes peuvent réguler la MF stromale sont des aides utiles pour diminuer le besoin de chirurgie radicale en cas de chirurgie étendue et agressive tumeurs odontogènes. Mots-clés: Améloblastome, AOT, OKC/KCOT, p53, α-SMA, myofibroblastes, tumeurs odontogènes, immunoréactivité.

Giant Cell Lesions of the Jaws:A Review and Comparative Histopathological Study.

BACKGROUND AND OBJECTIVES: Giant cell lesions (GCLs) are rare lesions which prominently feature multinucleated giant cells in their histology. They include central giant cell granuloma (CGCG), giant cell tumour of bone (GCT), peripheral giant cell granuloma (PGCG), Cherubism (CHB), e.t.c. This study reviewed the clinico-demographic parameters of GCLs of the jaws and assessed the giant cells. METHODS: This was a retrospective study examining the histopathology records of which part of the body of two tertiary institutions. All entries of cases diagnosed as GCLs were retrieved and data were extracted. Also, the giant cells in tissue sections were assessed. Data were analysed using SPSS Inc. version 20 while Chi square test was used to test for association. This was considered significant quand p < 0.05. RESULTS: Over the study period, 2,862 biopsy reports were reviewed. GCLs constituted 48(1.7%) and M: F ratio was 1:1.6 while majority occurred in the 2nd and 3rd decades. The mandible was the most common site recording 27(56.3%) cases and CGCG was the most frequently diagnosed GCL constituting 22(45.8%). Assessment of the giant cells revealed CGCG had predominantly large giant cells, a dense dispersal of giant cells and irregularly shaped giant cells, while CHB mainly had large giant cells with dense dispersal, but round shaped giant cells. CONCLUSION: GCLs are rare lesions commonly seen in females in the 2nd and 3rd decades of life with preference for the mandible. CGCG was the most commonly encountered lesion, while the giant cells in CGCG and CHB were similar in size as well as dispersal.