Immunoexpression of BRAF, EGFR and CD10 in ameloblastoma.

The ameloblastoma is the most challenging odontogenic neoplasm to treat because of its locallyinvasive behaviour, severe clinical implication, risk of malignant transformation and high recurrence rate. Recent evidence suggests that BRAF, EGFR and CD10 have a role in the local invasiveness of ameloblastoma. However, the spatial distribution characteristics of these pro-invasive factors and their association with clinical parameters in this neoplasm are largely unexplored. We sought to address these issues in ameloblastoma subtypes and to determine their biological relevance. Nineteen unicystic (UA) and 20 conventional ameloblastoma (SMA) were subjected to immunohistochemical staining for BRAF, EGFR and CD10, and semiquantitative analysis was performed. All ameloblastoma cases (n=39/39; 100%) exhibited a BRAF+/EGFR+/CD10+immunoprofile. Their expression rates were significantly higher in SMA than UA (P<0.05). BRAF, essential for the progression and proliferation of ameloblastoma, was detected mainly in the cytoplasm of stellate reticulum-like>stromal>preameloblast- like cells (P<0.05). EGFR, a potent oncogenic protein, showed predominantly nuclear localisation. CD10, an apoptosis-inhibitory factor, was strongly expressed in the membrane of stellate reticulum-like cells. Taken together, present results suggest that the spatial distribution patterns of BRAF, EGFR and CD10 parallel the specific behaviours of SMA and UA. Their cellular and intracellular protein localisations have important targeted therapy implications.

Parenchyma-stromal interleukin-1 alpha and interleukin-6 overexpressions in ameloblastoma correlate with the aggressive phenotype.

INTRODUCTION: Ameloblastoma is a benign but locally invasive odontogenic epithelial neoplasm with a high recurrence rate after treatment. The two main subsets encountered clinically are unicystic (UA) and solid/multicystic ameloblastoma (SMA). Currently neoplastic progression of many tumour types are believed to be related to parenchyma-stromal cell-cell interactions mediated by cytokines notably interleukins (IL). However their roles in ameloblastoma remain ill-understood. MATERIALS AND METHODS: Thirty-nine formalin-fixed paraffin-embedded ameloblastoma cases comprising unicystic ameloblastoma (n=19) and solid/multicystic ameloblastoma (n=20) were subjected to IHC staining for IL-1α, IL-1ß, IL-6 and IL-8. A semi-quantitative method was used to evaluate the expression levels of these cytokines according to cell types in the tumoural parenchyma and stroma. RESULTS: Major findings were upregulations of IL-1α and IL-6 in SMA compared to UA. Both cytokines were heterogeneously detected in the tumoural parenchyma and stroma. Within the neoplastic epithelial compartment, IL-1α expression was more frequently detected in PA-like cells in UA whereas it was more frequently encountered in SR-like cells in SMA. IL-6 demonstrated higher expression levels in the stromal compartment of SMA. IL-1ß and IL-8 were markedly underexpressed in both tumour subsets. CONCLUSIONS: Overexpression of IL-1α in SMA suggests that this growth factor might play a role in promoting bone resorption and local invasiveness in this subtype. The expression levels of IL-1α and IL-6 in three cellular localizations indicate that parenchymal-stromal components of ameloblastoma interact reciprocally via IL-1α and IL-6 to create a microenvironment conducive for tumour progression.

The prevalence of tongue lesions in Malaysian dental outpatients from the Klang Valley area.

OBJECTIVES: To determine the prevalence of tongue lesions in Malaysian dental outpatients from the Klang Valley area. SUBJECTS AND METHODS: A cross sectional study was conducted on 600 Malaysian outpatients (257 men, 343 women, mean age, 37.7 years) attending the Primary Dental Care Unit at the Faculty of Dentistry, University of Malaya. Demographic and medical data were recorded for all respondents. RESULTS: One hundred eighty-one patients (30.2%) (81 men, 100 women, mean age 42.0 years) were diagnosed with at least one tongue lesion (n = 207) at the time of examination. Of these, 24 patients (4%) had two or more tongue lesions present synchronously. Seven different lesions were diagnosed: fissured tongue (13.8%), crenated tongue (7.8%), pigmented tongue (6.2%), geographic tongue (2.2%), ankyloglossia (1.7%), hairy tongue (1.0%) and median rhomboid glossitis (0.2%). Their racial prevalences were Malays (n = 65, 10.8%), Indians (n = 62, 10.3%), Chinese (n = 53, 8.8%) and other race (n = 1, 0.2%). A significant relationship was observed between crenated tongue and race; between four types of tongue lesions (fissured tongue, geographic tongue, crenated tongue and pigmented tongue) and age; and between fissured tongue and gender (P < 0.05). CONCLUSIONS: Distribution characteristics of tongue lesions in Malaysians are important as local reference data in the daily clinical practice.

Strawberry gingivitis as the first presenting sign of Wegener's granulomatosis: report of a case.

Wegener's granulomatosis is a rare multi-system disease characterized by the classic triad of necrotizing granulomas affecting the upper and lower respiratory tracts, disseminated vasculitis and glomerulonephritis. Oral lesions as a presenting feature are only encountered in 2% of these cases. Hyperplastic gingival lesions or strawberry gingivitis, is a characteristic sign of Wegener's granulomatosis. The latter consists of reddish-purple exophytic gingival swellings with petechial haemorrhages thus resembling strawberries. Recognition of this feature is of utmost importance for timely diagnosis and definitive management of this potentially fatal disease. A case of strawberry gingivitis as the first presenting sign of Wegener's granulomatosis affecting a 50-year-old Malay male is reported here. The differential diagnosis of red lesions that may present in the gingiva is discussed.

Notch signaling and ghost cell fate in the calcifying cystic odontogenic tumor.

Notch signaling is an evolutionarily conserved mechanism that enables adjacent cells to adopt different fates. Ghost cells (GCs) are anucleate cells with homogeneous pale eosinophilic cytoplasm and very pale to clear central areas (previous nucleus sites). Although GCs are present in a variety of odontogenic lesions notably the calcifying cystic odontogenic tumor (CCOT), their nature and process of formation remains elusive. The aim of this study was to investigate the role of Notch signaling in the cell fate specification of GCs in CCOT. Immunohistochemical staining for four Notch receptors (Notch1, Notch2, Notch3 and Notch4) and three ligands (Jagged1, Jagged2 and Delta1) was performed on archival tissues of five CCOT cases. Level of positivity was quantified as negative (0), mild (+), moderate (2+) and strong (3+). Results revealed that GCs demonstrated overexpression for Notch1 and Jagged1 suggesting that Notch1-Jagged1 signaling might serve as the main transduction mechanism in cell fate decision for GCs in CCOT. Protein localizations were largely membranous and/or cytoplasmic. Mineralized GCs also stained positive implicating that the calcification process might be associated with upregulation of these molecules. The other Notch receptors and ligands were weak to absent in GCs and tumoral epithelium. Stromal endothelium and fibroblasts were stained variably positive.

Squamous odontogenic tumor of the mandible: a case report demonstrating immunoexpression of Notch1, 3, 4, Jagged1 and Delta1.

BACKGROUND: Squamous odontogenic tumor (SOT) is a rare benign odontogenic epithelial neoplasm. A slow-growing painless expansive swelling is the common presenting symptom. Histopathologically, SOT can be easily misdiagnosed as an acanthomatous ameloblastoma. Although Notch receptors and ligands have been shown to play a role in cell fate decisions in ameloblastomas, the role of these cell signaling molecules in SOT is unknown. CASE REPORT: This paper describes a case of SOT affecting the anterior mandible of a 10-year-old Indian female. The patient was treated by local surgical excision and there has been no follow-up clinical record of recurrence 5 years after primary treatment. Histo?pathological examination revealed a solid, locally-infiltrative neoplasm composed of bland-looking squamatoid islands scattered in a mature fibrous connective tissue stroma and the diagnosis was SOT. Immunohistochemical evaluation showed positive reactivity of varying intensity in the neoplastic epithelial cells for Notch1, Notch3, Notch4, and their ligands Jagged1 and Delta1. Expression patterns showed considerable overlap. No immunoreactivity was detected for Notch2 and Jagged2. CONCLUSIONS: Present findings suggest that Notch receptors and their ligands play differential roles in the cytodifferentiation of SOT.

An unsuspected ameloblastoma in the subpontic region of the mandible with consideration of pathogenesis from the radiographic course.

The purpose of this report is to document a case of unsuspected ameloblastoma involving the right man dibular subpontic region in a 38-year-old Cambodian female patient. This lesion was purportedly preceded by multiple radiolucencies which were diagnosed as radicular cysts and treated a few times in the past years by enucleation followed by endodontic therapy of the affected teeth. Bridgework restoration of the partially edentulous area was performed. This case report demonstrates radiographic changes that occurred in the periods before and after the diagnosis of ameloblastoma. The case may represent an example of radicular cysts and ameloblastoma occurring as a collision phenomenon, or the ameloblastoma may have arisen as a result of neoplastic transformation of the lining epithelium in an inflammatory odontogenic epithelial cyst.

Notch signaling in benign and malignant ameloblastic neoplasms.

BACKGROUND: In general, Notch is a representative signal which controls morphosis and differentiation of cells, but its role in human odontogenic neoplasms, especially in ameloblastoma and its malignant counterpart, ameloblastic carcinoma, is not known. METHODS: We examined Notch1 peptide and its gene (mRNA) in an ameloblastoma (case 1: 27-year-old female, right mandibular tumor) and an ameloblastic carcinoma (case 2: 93-year-old female, right mandibular tumor), using immunohistochemistry (IHC) and in situ hybridization (ISH) techniques. RESULTS: Notch1 intracellular domain (NICD) positive products were observed in the cells at the peripheral layer of most proliferating epithelial tumor nests in case 1. In case 2, positive products were similarly detected. In particular, small numbers of mitoses were identified in the nuclear region with intense NICD positive reaction. CONCLUSIONS: Notch signaling plays some role in cytological differentiation or acquisition of tissue specific characteristics in neoplastic cells of odontogenic neoplasms, including ameloblastoma and ameloblastic carcinoma. Notch1 may also contribute to cell cycle arrest induced by Notch1 activation in ameloblastic carcinoma.

Chemiluminescence as a diagnostic aid in the detection of oral cancer and potentially malignant epithelial lesions.

Chemiluminescence was evaluated as a diagnostic aid in the detection of oral cancer and potentially malignant epithelial lesions (PMELs) by comparing it against 1% tolonium chloride mouth rinse. Forty-six clinically identified lesions [14 primary squamous cell carcinoma (SCC), 26 PMELs and 6 benign lesions] and five cases of normal oral mucosa from 40 subjects (inclusive of 10 previously treated SCC cases) were examined with a commercial chemiluminescent kit (Vizilite) and tolonium chloride. Biopsy and histological verification of 31 lesions disclosed 14 SCC (45.2%), 10 epithelial dysplasias (32.3%), 5 lichen planus (16.1%) and 2 benign lesions (6.4%). For the remaining 15 lesions, a biopsy was not performed owing to patient's lack of consent or ill-health. The five cases of normal oral mucosa which tested negative for both tools were also not biopsied for ethical reasons. Sensitivity for Vizilite and tolonium chloride was 100% and 70.3%, respectively; and specificity was 14.2% for Vizilite and 25% for tolonium chloride. Their accuracy was 80.6% and 64.5%, respectively. Current findings suggest that chemiluminescence is a more reliable diagnostic tool than tolonium chloride in the detection of oral cancer and PMELs, and for follow-up of patients treated for the same.

Oral candidal species among smokers and non-smokers.

OBJECTIVE: To determine the various oral Candidal species among healthy Malaysian adults. DESIGN: Case-control study. PLACE AND DURATION OF STUDY: This study was collaborated between the Department of Medical Microbiology, Faculty of Medicine and Department of Oral Pathology, Oral Medicine and Periodontology, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia, between September 2002 till January 2004. PATIENTS AND METHODS: One hundred adults (50 smokers and 50 non-smokers), aged between 40 and 70 years were studied. Swabs and carbohydrate assimilation (Saboraud Dextrose Agar, Corn Meal Agar, API 20C AUX System) were performed. Specimens were collected from dorsum of the tongue, buccal mucosa and commissures (right and left each). Colony forms were established by positive colony forming units, on SDA medium (24-48 hours). Germ tube test for (true/pseudohyphae) growth was done on Corn Meal Agar Medium. Candida biotypes were evaluated by API 20C AUX system, which had a numerical 7 digit profile, added to evaluate a definite Candida species. RESULTS: Thirty-five percent of Malaysian adults harbored Candida intraorally. Candidal species identified among 100 subjects had C. albicans (27) 77%, C. glabrata (3) 8%, C. famata, C. tropicalis, C. krusei, C. lusitaniae and C. guilliermondii (1) 3% each. Thirty-three positive cases comprised of 35 species i.e. two cases had two species each. Fifty seven percent of these were smokers and 43% non-smokers. These included 40% Chinese, 36% Malays and 24% Indians. Species were, however, not specified according to intra-oral sites i.e. buccal, commissural mucosa and dorsum of tongue. CONCLUSION: On this series C. albicans is the most common species found in the oral cavity of Malaysian adults. It is equally frequent in smokers and non-smokers, but showed a predilection for the ethnic Chinese group.

Localization of type IV collagen a 1 to a 6 chains in basement membrane during mouse molar germ development.

The dental basement membrane (BM) putatively mediates epithelial-mesenchymal interactions during tooth morphogenesis and cytodifferentiation. Type IV collagen alpha chains, a major network-forming protein of the dental BM, was studied and results disclosed distinct expression patterns at different stages of mouse molar germ development. At the dental placode and bud stage, the BM of the oral epithelium expressed alpha 1, alpha 2, alpha 5 and alpha 6 chains while the gubernaculum dentis, in addition to the above four chains, also expressed a 4 chain. An asymmetrical expression for alpha 4, alpha 5 and alpha 6 chains was observed at the bud stage. At the early bell stage, the BM associated with the inner enamel epithelium (IEE) of molar germ expressed alpha 1, alpha 2 and alpha 4 chains while the BM of the outer enamel epithelium (OEE) expressed only alpha 1 and a 2 chains. With the onset of dentinogenesis, the collagen a chain profile of the IEE BM gradually disappeared. Howeverfrom the early to late bell stage, the gubernaculum dentis consistently expressed alpha 1, alpha 2, alpha 5 and a 6 chains resembling fetal oral mucosa. These findings suggest that stage- and position-specific distribution of type IV collagen alpha subunits occur during molar germ development and that these changes are essential for molar morphogenesis and cytodifferentiation.

Peri-implant bone reactions to immediately loaded implants. An experimental study in monkeys.

BACKGROUND: There are reports which demonstrate that immediately loaded splinted implants can be osseointegrated when they are placed in the anterior part of the lower jaw. The concept of immediate loading has not been well investigated in the posterior mandible. The aim of this study was to evaluate the bone reactions around immediately loaded implants placed in the posterior region of the lower jaw in the monkey model. METHODS: Six adult Macaca fascicularis monkeys were used in this study. A total of 36 implants were placed after extraction of the second premolars, first and second molars, and complete healing of the sockets. Three control (C) group implants were placed in one quadrant of the lower jaw of each monkey. After a delay of 3 months to allow osseointegration to take place, the implants were loaded for 1 month using temporary resin bridges and later for 2 months using metal splinted crowns. In the contralateral region of the lower jaw, 3 test (T) group implants were placed and loaded immediately with the same sequence as carried out for the C implants. Specimens were examined and evaluated histologically after sacrifice. RESULTS: All of the implants were osseointegrated. Compact, cortical bone in contact with the implant surface without any gaps or connective tissue formation was observed. CONCLUSIONS: It was concluded that immediately loaded, splinted implants can be osseointegrated with a similar hard and soft tissue peri-implant response as delayed-loaded implants in the posterior mandible.

Quantitative histological analysis of the human coronal dentine in dentinogenesis imperfecta types I and II.

The coronal dentine of 3 teeth from dentinogenesis imperfecta (DI) type I, 9 teeth from DI type II and 4 controls were examined by a quantitative histological technique. In each case, two representative demineralized sections, one stained in H + E and the other in Schmorl's picrothionin were used. The relative amount of dentinal tubule, atubular dentine and canals/clefts were assessed using the point-counting method. Three basic patterns of distribution of tubules were observed. Pattern 1 formed the largest group and showed a gradual decrease in tubule count from enamel-dentine junction (EDJ) pulpwards, pattern 2 was characterized by a drop in tubule count approximately midway between EDJ and pulpal border, and pattern 3 exhibited a gradual increase in tubule score as the pulp was approached. At the 5 per cent level, both patterns 1 and 2 were found to be statistically significant. Pattern 3 was statistically insignificant for the test specimens and highly significant for the controls. The variation in the distribution of the tubules in coronal dentine in this study indirectly supports the concept of abnormal dentinogenesis in DI attributable to a diminution or lack of normal functional odontoblasts.

Squamous cell carcinoma in an orthokeratinised odontogenic keratocyst.

Clinicopathological differences between the typical parakeratinised odontogenic keratocyst (OKC) and the orthokeratinised variant are outlined. A case conforming to the histological criteria of an orthokeratinised OKC occurring in association with a squamous cell carcinoma is described and possible relationships between the two entities discussed.

Review of oral histoplasmosis in Malaysians.

We reviewed biopsy records for 37 cases of oral histoplasmosis for patient characteristics, clinical features, and histopathologic findings. These represented cases diagnosed in the Division of Stomatology, Institute for Medical Research, Kuala Lumpur between July 1967 and October 1994. All were male patients who ranged in age from 11 to 79 years (mean age, 56.7 years). There were 40.6% Malays, 37.8% Chinese, 18.9% Indians, and 2.7% other races. Five patients with mouth lesions as the initial presenting lesions were proven to be cases of disseminated histoplasmosis. In the remaining cases apart from the biopsy-proven oral histoplasmosis lesions, the extent of the disease elsewhere was unknown. The majority of these lesions involved the gingiva, tongue, and palate in decreasing order of frequency. The most frequent presenting symptom was oral mucosal ulceration. Squamous cell carcinoma and tuberculosis were the two most common clinical differential diagnoses. Our present findings compare favorably with published reports from other regions.

Oral biopsy turnaround time: 20-year experience of the Department of Oral Pathology, Oral Medicine and Periodontology, Faculty of Dentistry, University of Malaya.

The turnaround time (TAT) for oral biopsies received for histological examination by the Department of Oral Pathology, Oral Medicine and Periodontology, Faculty of Dentistry, University of Malaya, for the years 1978, 1988 and 1998 was evaluated. For the three years studied, TATs for 61, 233 and 463 specimens were retrospectively analysed. Testing intervals, that is, from the dates the surgeons procured the specimens, the laboratories accessioned them and until the pathologists signed off the diagnoses, were used to calculate TAT. The performance level of the respective pathologists, the growth of tissue diagnostic services and the possible variables that influence TAT were also evaluated. As prompt diagnosis means prompt treatment, which in turn has a bearing on prognosis, the TAT pertinent to oral malignant tumors was emphasized. The mean TAT, its mode and median fell significantly in 1998 compared with the previous 2 years; it was lower for soft tissue than for hard tissue specimens, and lower for malignant, than for non-malignant specimens. The progression of tissue diagnostic services is up to a satisfactory level, as 88.89 % of biopsies could render diagnoses within a fair period of time in 1998.

A clinicopathological and immunohistochemical study of the calcifying epithelial odontogenic tumour (Pindborg tumour) in Malaysians.

We reviewed the clinicopathological characteristics of 13 cases of calcifying epithelial odontogenic tumour (CEOT) (Pindborg tumour) diagnosed in the Division on Stomatology, Institute for Medical Research, Kuala Lumpur, over a 29-year period. There were eight female and five male patients. These consisted of eight (61.5 per cent) Malays, three (23.1 per cent) Chinese, one (7.7 per cent) Indian and one (7.7 per cent) Melanau. Their ages at presentation ranged from 19-61 years (mean age, 31.8 years). There were 12 central and one peripheral CEOT. Of these, 76.9 per cent of cases were located in the maxilla, the remaining in the mandible. The commonest clinical diagnosis was a dentigerous cyst (66.7 per cent). Enucleation was the main mode of treatment. Histologically, sheets and strands of polyhedral epithelial cells containing eosinophilic, homogeneous globules with Liesegang rings were observed. One case also showed extensive calcification and clear cell differentiation. Immunohistochemistry revealed a variable keratin staining of the CEOT epithelium, confirming its heterogeneity.

Aggressive (malignant?) epithelial odontogenic ghost cell tumour of the maxilla.

A case is described of ameloblastoma of the mandible presenting with multiple recurrences and subsequent extension to the maxilla with resultant transformation into an aggressive (malignant?) epithelial odontogenic ghost cell tumour. The latter is a rare, biologically virulent entity that affects mainly males, exhibits a preference for the maxilla and is histologically characterized by atypical malignant odontogenic epithelium associated with areas of ghost cell formation and varying amounts of dentinoid.

Atypical peripheral ameloblastoma of the palate.

Clinical, radiological and histological characteristics of the peripheral ameloblastoma are briefly outlined. A case found occurring in the palate and presenting with atypical histological features is reported. The differential diagnosis of this lesion, its treatment and histogenesis are discussed.

Squamous cell carcinoma of the oral mucosa in Malaysia--any change?

The prevalence rate of 749 cases of oral squamous cell carcinomas (SCC) recorded between 1978-1984 was studied. Results showed that the Indians formed the dominant group (63.8%) followed by the Malays (19.6%) and Chinese (16.6%). The peak incidences were generally located between the sixth and eighth decades. Only in the Chinese group a male preponderance was noted. In the Indians, the buccal mucosa was the most prevalent site; in the Malays and Chinese males, the gingiva and alveolus; and the Chinese female, the tongue. In all three groups, the well-differentiated SCC was the commonest type and the poorly differentiated least common.