Epithelial-to-mesenchymal transition in ameloblastoma: focus on morphologically evident mesenchymal phenotypic transition.

The ameloblastoma is the most common and clinically significant odontogenic epithelial neoplasm known for its locally-invasive behaviour and high recurrence risk. Epithelial-to-mesenchymal transition (EMT) is a fundamental process whereby epithelial cells lose their epithelial characteristics and gain mesenchymal properties. EMT induction via transcription repression has been investigated in ameloblastoma.

Invadopodia proteins, cortactin, N-WASP and WIP differentially promote local invasiveness in ameloblastoma.

Background: Cell migration and invasion through interstitial tissues are dependent upon several specialized characteristics of the migratory cell notably generation of proteolytic membranous protrusions or invadopodia. Ameloblastoma is a benign odontogenic epithelial neoplasm with a locally infiltrative behaviour. Cortactin and MMT1-MMP are two invadopodia proteins implicated in its local invasiveness.

RANK, RANKL, and OPG in recurrent solid/multicystic ameloblastoma: their distribution patterns and biologic significance.

Objectives: To determine the distribution patterns of bone resorption regulators, receptor activator of nuclear factor κ-B (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) in recurrent ameloblastoma (RAs) and to clarify their impact on the biologic behavior of these neoplasms.

Materials And Methods: Fifteen paraffin-embedded RA cases were subjected to immunohistochemistry for expression of RANK, RANKL, and OPG.

Results: The RANK-RANKL-OPG triad was heterogeneously detected in RA samples.

Comparative assessment of the interfacial soft and hard tissues investing implants and natural teeth in the macaque mandible.

Objectives: The aim of this study was to conduct a comparative qualitative and quantitative assessment of the interfacial soft and hard tissues investing implants and natural teeth.

Materials And Methods: The test sample consisted of six adult healthy male Macaca fascicularis with three-unit splinted crowns, each crown supported by an Ankylos screw-shaped titanium implant. These implants were placed in the mandibular premolar-second molar region, one side by an immediate-loading (IL) and the other by delayed-loading (DL) protocol.

Intra-epithelially entrapped blood vessels in ameloblastoma.

Background: The ameloblastoma is a benign but locally aggressive odontogenic neoplasm with a high recurrence rate. While significant progress has been made in our understanding regarding the role of tumoral vasculature relative to the diverse behavioral characteristics of this tumor, no attention has been paid to a distinct subset of blood vessels entrapped within its epithelial compartment. As vascular niches are known to influence tumoral growth, clarification of these vessels is important.

Podoplanin, E-cadherin, β-catenin, and CD44v6 in recurrent ameloblastoma: their distribution patterns and relevance.

Background: Ameloblastoma is a benign but locally infiltrative odontogenic epithelial neoplasm with a high risk for recurrence. Podoplanin, a lymphatic endothelium marker, putatively promotes collective cell migration and invasiveness in this neoplasm. However, its role in the recurrent ameloblastoma (RA) remains unclear.

Identifying factors associated with diagnostic concordance/discordance in oral lichen planus.

Purpose: To identify factors associated with concordance and discordance between clinical and histopathologic diagnoses of oral lichen planus lesions.

Materials And Methods: A retrospective analysis was conducted on all study cases derived from archival oral pathology reports generated from all cases of oral lichen planus accessioned by the Faculty of Dentistry, University of Malaya. These study cases were diagnosed from January 1980 through December 2010.

Differential expression of transcription factors Snail, Slug, SIP1, and Twist in ameloblastoma.

Background: Epithelial-to-mesenchymal transition (EMT) via the mechanism of transcription repression is a crucial process for the induction of invasiveness in many human tumors. Ameloblastoma is a benign odontogenic epithelial neoplasm with a locally infiltrative behavior. Twist, an EMT promoter, has been implicated in its invasiveness.

Cementum status in natural teeth opposing implant-borne bridgework in Macaca fascicularis.

Objective: The objective of this study was to investigate the cementum status in natural teeth opposing implant-supported bridgework.

Methods: Maxillary premolars and molars opposing immediate-loading (IL) and delayed-loading (DL) mandibular implant-supported bridgework in 4 Macaca fascicularis were harvested after 3 months of functional loading. Another 2 monkeys without mandibular fixed prostheses served as control.

Differential expression of canonical and non-canonical Wnt ligands in ameloblastoma.

Background: Canonical and non-canonical Wnt signaling pathways modulate diverse cellular processes during embryogenesis and post-natally. Their deregulations have been implicated in cancer development and progression. Wnt signaling is essential for odontogenesis.

Ameloblastoma of the jaws: a retrospective analysis of 340 cases in a Malaysian population.

Purpose: Ameloblastoma of the human jaw is an uncommon but clinically significant odontogenic epithelial neoplasm. The aim was to analyze the clinicopathologic characteristics of ameloblastoma in a Malaysian population.

Materials And Methods: This is a retrospective study (1993 through 2008) of consecutive ameloblastoma cases accessioned in 2 main oral pathology diagnostic centers: the Unit of Stomatology, Institute for Medical Research and the Department of Oral Pathology, Oral Medicine, and Periodontology, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia.

Subcutaneous reactions and degradation characteristics of collagenous and noncollagenous membranes in a macaque model.

Background: collagenous and noncollagenous membranes have been investigated in many animal systems but their effects in the macaque model are unknown.

Objective: to determine subcutaneous cellular reactions and degradation characteristics following implantation of collagenous and noncollagenous membranes in a macaque model.

Methods: six adult male Macaca fascicularis, aged above 7 years, were used.

Notch4 overexpression in ameloblastoma correlates with the solid/multicystic phenotype.

Objective: Notch signaling has been implicated in cell fate decisions during odontogenesis and tumorigenesis of some odontogenic neoplasms; however, its role in solid/multicystic (SA), unicystic (UA), and recurrent (RA) ameloblastoma remains unclear. The aim of this study was to determine Notch receptor and ligand expressions in these subtypes and to speculate on their significance.

Methods: Notch receptors (Notch1, 2, 3, 4) and ligands (Jagged1, 2, and Delta1) were examined immunohistochemically in SA (n = 23), UA (n = 22), and RA (n = 19).

Differential expression of Notch receptors and their ligands in desmoplastic ameloblastoma.

Background: In mammals, the Notch gene family encodes four receptors (Notch1-4), and all of them are important for cell fate decisions. Notch signaling pathway plays an essential role in tooth development. The ameloblastoma, a benign odontogenic epithelial neoplasm, histologically recapitulates the enamel organ at bell stage.

Heparanase and vascular endothelial growth factor expression in the progression of oral mucosal melanoma.

Oral mucosal melanoma is an aggressive neoplasm with poor prognosis. Heparanase is an endo-beta-d-glucuronidase, which cleaves heparan sulphate chains. The vascular endothelial growth factor (VEGF) is the most potent angiogenic mitogen and interaction with its receptor (VEGFR) has been associated with angiogenesis.

An updated clinical and epidemiological profile of the adenomatoid odontogenic tumour: a collaborative retrospective study.

Background: Adenomatoid odontogenic tumour (AOT) is a benign odontogenic jaw lesion. The aim of this study was to update the biological profile of AOT.

Material And Methods: Cases published in the literature and cases in files of co-authors were included.

Osteosarcoma presenting as an aggressive nodular mass in the region of the mandible.

Osteosarcomas are highly malignant neoplasms of bone that are challenging to diagnose. These neoplasms often show atypical behavior. In the initial phase they may present as nondescript bony swellings with an indolent growth rate, only to become overtly aggressive and malignant towards the later phase of the disease.

Osteoma of the condyle as the cause of limited-mouth opening: a case report.

Osteoma is a benign tumour consisting of mature bone tissue. It is an uncommon lesion that occurs mainly in the bones of the craniofacial complex. Only a few cases involving the condylar process have been reported.

Oral candidosis in non-Hodgkin's lymphoma: a case report.

Though oral candidosis is an opportunistic fungal infection that commonly affects immunocompromised patients, little is known of its occurrence as a complication of Non-Hodgkin's lymphoma. This paper reports a case of oral candidosis in a 20-year-old Indonesian woman with this lymphoproliferative disease. She presented with acute pseudomembranous candidosis on the dorsum and lateral borders of the tongue, bilateral angular cheilitis and cheilocandidosis.

Odontogenic keratocyst with dentinoid formation.

Although rare, hard tissue deposits, namely dystrophic calcifications and cartilage, have been reported to occur in the connective tissue wall of the odontogenic keratocyst. However, dentinoid formation has not been previously documented. A case involving the left mandibular premolar-molar region in a 37-year-old Malay male is described here along with a brief review on the reported prevalence of hard tissue deposits in the odontogenic keratocyst.

An immunohistochemical study of two cases of either peripheral odontogenic fibroma (WHO type) or peripheral ameloblastoma.

Two cases of either peripheral odontogenic fibroma (POF) (WHO type) or peripheral ameloblastoma are reported. Their immunohistochemical characteristics were investigated in an attempt to clarify their histogenesis. The results showed that the epithelial component of this neoplasm tended to retain its distinct odontogenic character and expressed a keratin profile different from that of the overlying oral epithelium from which both cases most probably originated.

Combined calcifying epithelial odontogenic tumor and adenomatoid odontogenic tumor.

A case of combined epithelial odontogenic tumor associated with an unerupted maxillary canine tooth is described. The relative proportion of adenomatoid odontogenic tumor tissue and calcifying epithelial odontogenic tumor areas in a given tumor in determining the behaviour and growth potential of this entity is discussed.