Characterization and potential roles of bone marrow-derived stromal cells in cancer development and metastasis.

Background: The tumor microenvironment and its stromal cells play an important role in cancer development and metastasis. Bone marrow-derived cells (BMDCs), a rich source of hematopoietic and mesenchymal stem cells, putatively contribute to this tumoral stroma. However their characteristics and roles within the tumor microenvironment are unclear. In the present study, BMDCs in the tumor microenvironment were traced using the green fluorescent protein (GFP) bone marrow transplantation model. Methods: C57BL/6 mice were irradiated and rescued by bone marrow transplantation from GFP-transgenic mice. Lewis lung cancer cells were inoculated into the mice to generate subcutaneous allograft tumors or lung metastases. Confocal microscopy, immunohistochemistry for GFP, α-SMA, CD11b, CD31, CD34 and CD105, and double-fluorescent immunohistochemistry for GFP-CD11b, GFP-CD105 and GFP-CD31 were performed. Results: Round and dendritic-shaped GFP-positive mononuclear cells constituted a significant stromal subpopulation in primary tumor peripheral area (PA) and metastatic tumor area (MA) microenvironment, thus implicating an invasive and metastatic role for these cells. CD11b co-expression in GFP-positive cells suggests that round/dendritic cell subpopulations are possibly BM-derived macrophages. Identification of GFP-positive mononuclear infiltrates co-expressing CD31 suggests that these cells might be BM-derived angioblasts, whereas their non-reactivity for CD34, CD105 and α-SMA implies an altered vascular phenotype distinct from endothelial cells. Significant upregulation of GFP-positive, CD31-positive and GFP/CD31 double-positive cell densities positively correlated with PA and MA (P<0.05). Conclusion: Taken together, in vivo evidence of traceable GFP-positive BMDCs in primary and metastatic tumor microenvironment suggests that recruited BMDCs might partake in cancer invasion and metastasis, possess multilineage potency and promote angiogenesis.

Spatial distribution of osteopontin, CD44v6 and podoplanin in the lining epithelium of odontogenic keratocyst, and their biological relevance.

BACKGROUND AND AIMS: The odontogenic keratocyst (OKC) remains the most challenging jaw cyst to treat because of its locally-aggressive behaviour and high recurrence potential. Emerging evidence suggests that osteopontin, its receptors CD44v6 and integrin αv, and podoplanin, have a role in the local invasiveness of this cyst. However the spatial distribution characteristics of these pro-invasive markers in the lining epithelium of OKC, and their association with the clinicopathologic parameters of OKC are largely unexplored. This study sought to address these issues in comparison with dentigerous cysts (DCs) and radicular cysts (RCs) and to evaluate their biological relevance. METHODS: A sample consisting of 20 OKC cases, 10 DCs and 10 RCs was subjected to immunohistochemical staining for osteopontin, CD44v6 and integrin αv, and podoplanin, and semiquantitative analysis was performed. RESULTS: All factors (except integrin αv) were detected heterogeneously in the constitutive layers of the lining epithelium in all three cyst types. Key observations were significant upregulation of CD44v6 and podoplanin in OKC compared to DCs and RCs, suggesting that these protein molecules may play crucial roles in promoting local invasiveness in OKC (P<0.05). Osteopontin underexpression and distribution patterns were indistinctive among all three cysts indicating its limited role as pro-invasive factor. Clinical parameters showed no significant correlations with all protein factors investigated. CONCLUSIONS: Present findings suggest that an osteopontinlow CD44v6high and podoplaninhigh immunoprofile most probably represent epithelial signatures of OKC and are markers of local invasiveness in this cyst.

Parenchyma-stromal interactions induce fibrosis by secreting CCN2 and promote osteoclastogenesis by stimulating RANKL and CD68 through activated TGF-ß/BMP4 in ameloblastoma.

BACKGROUND: Tumor parenchyma-stromal interactions affect the properties of tumors and their dynamics. Our group previously showed that secreted frizzled related protein (sFRP)-2 impairs bone formation and promotes bone invasion in ameloblastoma. However, the effects of the secreted growth factors CCN2, TGF-ß, and BMP4 on stromal tissues in ameloblastoma remain unclear. MATERIALS AND RESULTS: Thirty-five paraffin-embedded ameloblastoma cases, ameloblastoma-derived cell lines (AM-1), and primary cultures of ameloblastoma stromal fibroblasts (ASF) were used. Immunohistochemistry, MTT assay, Western blotting, and RT-PCR were performed on these samples. Parenchyma-stromal CCN2 overexpression correlated significantly with fibrous-type stroma, but not with myxoid-type stroma, suggesting a role of CCN2 in fibrosis (P < 0.05). Recombinant CCN2 induction of enhanced ASF proliferation in AM-1 medium supports this view. Conversely, BMP4 and TGF-ß were expressed in myxoid-type fibroblasts, but little expression was found in parenchyma. RANKL-positive and CD68-positive stromal cell populations were significantly greater in myxoid-type tumor areas than in fibrous-type tumor areas, while a higher Ki-67 labeling index was recorded in ameloblastoma with fibrous-type stroma. These data suggest that stromal properties influence bone resorption-related activities and growth rates, respectively. CONCLUSIONS: These results suggest that the effects of secreted growth factors are governed by ameloblastoma parenchyma-stromal interactions. CCN2 promotes fibrogenesis independent of TGF-ß signaling. Absence of CCN2 expression is associated with a phenotypic switch to a myxoid-type microenvironment that is conducive for TGF-ß/BMP4 signaling to promote osteoclastogenesis.

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. Other invadopodia regulators, namely N-WASP, WIP and Src kinase remain unclarified. This study addresses their roles in ameloblastoma. MATERIALS AND METHOD: Eighty-seven paraffin-embedded ameloblastoma cases (20 unicystic, 47 solid/multicystic, 3 desmoplastic and 17 recurrent) were subjected to immunohistochemistry for expression of cortactin, N-WASP, WIP, Src kinase and F-actin, and findings correlated with clinicopathological parameters. RESULTS: Invadopodia proteins (except Src kinase) and F-actin were widely detected in ameloblastoma (cortactin: n = 73/87, 83.9%; N-WASP: n = 59/87; 67.8%; WIP: n = 77/87; 88.5%; and F-actin: n = 87/87, 100%). Protein localization was mainly cytoplasmic and/or membranous, and occasionally nuclear for F-actin. Cortactin, which functions as an actin-scaffolding protein, demonstrated significantly higher expression levels within ameloblastoma tumoral epithelium than in stroma (P < 0.05). N-WASP, which coordinates actin polymerization and invadopodia-mediated extracellular matrix degradation, was overexpressed in the solid/multicystic subtype (P < 0.05). WIP, an upstream regulator of N-WASP, and F-actin were significantly upregulated along the tumour invasive front compared to tumour centres (P < 0.05). Except for males with cortactin overexpression, other clinical parameters (age, ethnicity and anatomical site) showed no significant correlations. CONCLUSIONS: Present results suggest that local invasiveness of ameloblastoma is dependent upon the migratory potential of its tumour cells as defined by their distribution of cortactin, N-WASP and WIP in correlation with F-actin cytoskeletal dynamics.

Oral Thrush of Tongue with Erythematous 'Kissing Lesion' on the Palate Complicating Fixed Orthodontic Appliance Therapy.

Oral candidiasis is a well-recognized opportunistic fungal infection whereas orthodontic therapy is a well-established treatment with few risks. We report here an unusual case of oral thrush of tongue with erythematous palatal 'kissing lesion' in an otherwise healthy 16-year-old girl, complicated by her fixed orthodontic appliance and low salivary pH.

Podoplanin, E-cadherin, ß-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. As morphological, signaling, and genetic differences may exist between primary and recurrent tumors, clarification of their distribution patterns is of relevance. MATERIALS AND METHODS: Podoplanin was examined immunohistochemically in conjunction with E-cadherin, ß-catenin, and CD44v6 in 25 RA. Immunostaining according to tumor area, cellular type, and location, and relationship of these proteins were analyzed. Findings were compared with 25 unrelated primary ameloblastomas (UPA). RESULTS: All four proteins were detected in RA and UPA samples. Expression rates for each protein were not significantly different between these two groups. RA demonstrated significant upregulation of podoplanin at the invasive front (P < 0.05), whereas upregulation of ß-catenin and CD44v6 and downregulation of E-cadherin at this site were not statistically significant (P > 0.05). Immunolocalization for all four proteins was predominantly membranous and less frequently cytoplasmic. Pre-ameloblast-like cells were podoplanin(+) /CD44v6(-), while stellate reticulum-like cells were podoplanin(-)/CD44v6(+). Acanthomatous, granular cell, and desmoplastic variants in both RA and UPA were podoplanin(-/low) but stained weak-to-moderate for E-cadherin, ß-catenin, and CD44v6. Stromal fibroblasts and lymph channels were variably podoplanin-positive. CONCLUSIONS: Podoplanin, ß-catenin, and CD44v6 upregulation at the tumor invasive fronts in RA and UPA supports a differential regulatory role by these molecules in mediating collective cell migration and local invasiveness. E-cadherin downregulation suggests altered cell adhesion function during tumor progression.

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. The objectives of this study were to investigate the morphologic characteristics of intra-epithelially entrapped blood vessels (IEBVs) in ameloblastoma and to speculate on their relevance. MATERIALS AND METHOD: Here, we evaluated the frequency, microvessel density (MVD), morphology, and distribution pattern of IEBVs in 77 ameloblastoma of different subtypes based on their immunoreactivity for endothelial markers (CD34, CD31, CD105), vascular tight junction protein (claudin-5), pericyte [α-smooth muscle actin (α-sma)], and vascular basement membrane (collagen IV). RESULTS: IEBVs were heterogeneously detected in ameloblastoma. Their mean MVD (CD34 = 15.46 ± 7.25; CD31 = 15.8 ± 5.04; CD105 = 0.82 ± 0.51) showed no significant correlation with different subtypes, and between primary and recurrent tumors (P > 0.05). These microvessels may occur as single/clusters of capillary sprouts, or formed compressed branching/non-branching slits entrapped within the epithelial compartment, and in direct apposition with polyhedral/granular neoplastic epithelial cells. They expressed proteins for endothelial tight junctions (claudin-5-positive) and pericytes (α-sma-positive) but had deficient basement membrane (collagen IV weak to absent). Aberrant expression for CD34, CD31, and CD105 in tumor epithelium was variably observed. CONCLUSIONS: Although rare in occurrence, identification of IEBVs in ameloblastoma could potentially represent a new paradigm for vascular assessment of this neoplasm.

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. The animals were sacrificed after 3 months of functional loading. Another two monkeys with natural dentition served as controls. Nondecalcified sections were prepared for assessment of optical intensities (OI) under a confocal laser scanning microscope. RESULTS: In both the test (IL and DL) and control, the soft tissue complexes demonstrated a highly fluorescent keratinized layer and diminished cytoplasmic and enhanced membranous fluorescence in the remaining epithelium. Peri-implant mucosa was further characterized by an intense fluorescence at the junctional epithelium-implant interface and in the stromal mononuclear infiltrate. Connective tissue contact and periodontal ligament were weakly fluorescent. In hard tissues, a high fluorescence was observed in peri-implant woven bone and along the implant-bone interface. Mean OI was significantly higher in peri-implant woven bone than around teeth (P < 0.05). In the remaining soft and hard tissue complexes, no significant differences in mean OI between the test and control were observed (P > 0.05). CONCLUSIONS: Present findings suggest that peri-implant woven bone is highly mineralized, while the peri-implant and gingival mucosa share structural similarities. CLINICAL RELEVANCE: Optical intensities of interfacial tissues investing implants and teeth are related to their biological properties.

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. The roles of the other transcription factors remain unclarified. MATERIALS AND METHODS: Four transcription factors, namely Snail, Slug, SIP1, and Twist, were examined immunohistochemically in 64 ameloblastoma [18 unicystic (UA), 20 solid/multicystic (SA), 4 desmoplastic (DA), and 22 recurrent (RA)]. RESULTS: All four transcription factors were differentially expressed in ameloblastoma [Snail: n = 60/64 (94%); Slug: n = 21/64 (33%); SIP: n = 18/64 (28%); Twist: n = 26/64 (41%)] (P < 0.05). Their distribution patterns were heterogeneous and were not significantly different between the tumor invasive front and central area (P > 0.05). Intracellular protein localization was predominantly nuclear for Snail, cytoplasmic>nuclear for Slug and SIP1, and cytoplasmic/nuclear for Twist. Overexpression of Snail in most subsets (UA = 18/18; SMA = 19/20; DA = 4/4; RA = 19/22) compared with the other transcription factors (P < 0.05) and selective expression for Slug, SIP1, and Twist in squamous/keratinous foci and at sites of epithelial cystic degeneration were among the main observations made. Stromal cells surrounding immunoreactive tumor cells tended to stain positive. CONCLUSIONS: Present findings suggest that these transcription factors probably play differential roles in mediating local invasiveness in ameloblastoma. Overexpression of Snail in most subsets suggests that this molecule is most likely the prototype transcription factor involved in inducing EMT in the ameloblastoma.

Histologic, histomorphometric, and cone-beam computerized tomography analyses of calcium sulfate and platelet-rich plasma in socket preservation: a pilot study.

OBJECTIVES: To assess dimensional changes and histologic/histomorphometric aspects of grafted sockets using either calcium sulfate-platelet-rich plasma (CS-PRP) or CS alone in socket preservation procedure. STUDY DESIGN: Twelve subjects with single nonmolar teeth underwent atraumatic extraction. Six sockets received CS grafts and 6 sockets received CS-PRP grafts. Cone-beam computerized tomography scans taken immediately after extraction and 4 months after surgery were used to measure vertical and horizontal dimensional changes. Histologic and histomorphometric analyses of grafted sites were performed at 4 months after surgery. Intergroup changes were compared using Mann-Whitney U test. RESULTS: CS group demonstrated 18.6% horizontal resorption as compared with 9.2% in CS-PRP group. Resorption for buccal height (BH) (14%) and palatal/lingual height (PH) (13.7%) in CS group was nearly 3 times more than resorption in BH (5%) and PH (4.6%) for CS-PRP group. Mineralized bone component in CS-PRP group (11.19% ± 6.59%) was significantly more than CS group (1.51% ± 2.86%) (P = 0.01). CONCLUSION: CS-PRP-grafted sites demonstrated higher mineralized bone content than CS-grafted sites.

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. Predictor variables were diagnosis year, demographics, experience of the examiner, clinical appearance and diagnosis, and final histopathologic diagnosis; these were recorded for each study case. The outcome variable was agreement between the clinical and histopathologic diagnoses, and this was classified as concordant or discordant. Descriptive statistics and multiple linear regression analyses were computed to identify associations between predictors and outcomes. Statistical significance was set at P ≤ .05. RESULTS: The sample was composed of 441 study cases with 593 oral mucosal lesions that met the inclusion criteria. The mean age of the sample was 47.5 ± 13.07 years (range, 12 to 82 yr) and 64.4% were female. The mean concordance was 83.2%. Diagnosis year and demographics showed no influence on concordance or discordance. The multiple linear regression model included experience of the examiner, clinical appearance and diagnosis, and final histopathologic diagnosis (R(2) = 0.82). Except for experience of the examiner (P = .12), clinical appearance and diagnosis and final histopathologic diagnosis were the variables statistically associated with concordance (P ≤ .01). CONCLUSIONS: The present results suggest that concordance is governed primarily by the clinical appearance and diagnosis of the lesion and the final histopathologic diagnosis.

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. The ameloblastoma is an odontogenic epithelial neoplasm of enamel organ origin. Altered expressions of Wnts-1, -2, -5a, and -10a are detected in this tumor. The activity of other Wnt members remains unclarified. MATERIALS AND METHODS: Canonical (Wnts-1, -2, -3, -8a, -8b, -10a, and -10b), non-canonical (Wnts-4, -5a, -5b, -6, 7a, -7b, and -11), and indeterminate groups (Wnts-2b and -9b) were examined immunohistochemically in 72 cases of ameloblastoma (19 unicystic [UA], 35 solid/multicystic [SMA], eight desmoplastic [DA], and 10 recurrent [RA]). RESULTS: Canonical Wnt proteins (except Wnt-10b) were heterogeneously expressed in ameloblastoma. Their distribution patterns were distinctive with some overlap. Protein localization was mainly membranous and/or cytoplasmic. Overexpression of Wnt-1 in most subsets (UA = 19/19; SMA = 35/35; DA = 5/8; RA = 7/10) (P < 0.05), Wnt-3 in granular cell variant (n = 3/3), and Wnt-8b in DA (n = 8/8) was key observations. Wnts-8a and -10a demonstrated enhanced expression in tumoral buddings and acanthomatous areas. Non-canonical and indeterminate Wnts were absent except for limited Wnt-7b immunoreactivity in UA (n = 1/19) and SMA (n = 1/35). Stromal components expressed variable Wnt positivity. CONCLUSION: Differential expression of Wnt ligands in different ameloblastoma subtypes suggests that the canonical and non-canonical Wnt pathways are selectively activated or repressed depending on the tumor cell differentiation status. Canonical Wnt pathway is most likely the main transduction pathway while Wnt-1 might be the key signaling molecule involved in ameloblastoma tumorigenesis.

Dimensional profile of oral mucosa around combined tooth-implant-supported bridgework in macaque mandible.

PURPOSE: A stable oral mucosa is crucial for long-term survival and biofunctionality of implants. Most of this evidence is derived from clinical and animal studies based solely on implant-supported prosthesis. Much less is known about the dimensions and relationships of this soft tissue complex investing tooth-implant-supported bridgework (TISB). The aim here was to obtain experimental evidence on the dimensional characteristics of oral mucosa around TISB with two different abutment designs. METHODS: Sixteen 3-unit TISB were constructed bilaterally in the mandible of eight adult Macaca fascicularis. An implant system with a standard progressive thread design was the bone-anchoring implant in the second mandibular molar region while the second mandibular premolar served as the natural tooth abutment. Eight implants were connected with the tapered abutment, the remaining with butt-joint abutment, in a split-mouth design. These were allowed to functional load for 6 months before sacrification for histomorphometry. Six soft tissue indices were scored: coronal gingival mucosa-to-implant top distance (DIM); sulcus depth (SD); junctional epithelium (JE); connective tissue contact (CTC); implant top to first bone-to-implant contact distance (DIB); and biologic width (BW=SD+JE+CTC); corresponding parameters in the natural tooth abutment were also measured. RESULTS: Mucosal dimensions in tapered implants (*BW=3.33±0.43; SD=1.03±0.24; JE=1.08±0.13; CTC=1.22±0.23 mm) were comparable with those of natural tooth abutments (BW=3.04±0.18; SD=0.93±0.1; JE=0.78±0.1; Attachment=1.33±0.09 mm), but differed from butt-joint implants (*BW=4.88±1.24; SD=1.47±0.38; JE=1.49±0.4; CTC=1.92±0.93 mm) (*P<0.05). CONCLUSIONS: Results suggested that soft tissue dimensions around TISB are influenced by the implant-abutment interface and abutment material used. Mucosa investing tapered abutment tends to recapitulate soft tissue physiologic dimensions of natural tooth.

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. Data on patient demographics, tumor location, symptomology, duration, radiographic appearance, preoperative diagnosis, clinicopathologic subtypes, treatment, and recurrence were analyzed. RESULTS: Three hundred forty cases of ameloblastoma were reviewed. These were from 197 male patients (57.9%) and 143 female patients (42.1%), with a male-to-female ratio of 1.4:1. A wide age range (7 to 85 years), mean onset age of 30.3 ± 16.3 years, and peak incidence in the second decade of life were recorded. Most were mandibular tumors (n = 311/340, 91.5%). These consisted of 95 (28%) unicystic ameloblastomas, 221 (65%) solid/multicystic ameloblastomas, 22 (6.4%) desmoplastic ameloblastoma, and 2 (0.6%) peripheral ameloblastomas. Unicystic ameloblastoma (41.1%) and solid/multicystic ameloblastoma (52.0%) mostly affected Malays patients, whereas desmoplastic ameloblastoma (59.1%) was prevalent in Chinese patients. Unicystic ameloblastoma (56.8%) and solid/multicystic ameloblastoma (47.1%) occurred predominantly in the body and posterior mandible, whereas desmoplastic ameloblastoma (36.4%) preferentially involved the anterior jaw segment. Most tumors presented as multilocular radiolucencies (36.8%). Enucleation (n = 42/92, 45.7%) was the treatment of choice. About 18 cases (13.3%) presented with recurrence. CONCLUSIONS: Because ameloblastoma subsets differ in their biologic behavior, the present data are significant as baseline references for clinicians and pathologists.

Prevalence of bilateral 'mirror-image' lesions in patients with oral potentially malignant epithelial lesions.

Early detection of oral potentially malignant epithelial lesions (PMELs) is aimed at improving survival rates as carcinogenesis is a multistep process and prevention is possible if these lesions are detected at an early and reversible stage of the disease. A prospective clinical study aimed at determining the prevalence of bilateral 'mirror-image' oral PMELs was carried out. Sample consisted of 32 (53.3%) Indians, 23 (38.3%) Chinese, 4 (6.7%) Malays and one (1.7%) Nepalese. All had histopathological confirmation of their primary existing PMEL as inclusion criteria. A total of 70 primary lesions were detected. The most common PMEL found was oral lichen planus. Of these, 28 (46.7%) patients exhibited bilateral 'mirror-image' lesions (n = 42) either synchronously (n = 32/42) or metachronously (n = 10/42). The remaining 32 (53.3%) patients had normal-looking contralateral mucosa. Present findings suggest that patients presenting with oral PMELs are at greater risk of developing a second lesion, most probably in the contralateral 'mirror-image' site.

Heparanase and cyclooxygenase-2 gene and protein expressions during progression of oral epithelial dysplasia to carcinoma.

Heparanase and cyclooxygenase-2 (COX-2) are 2 key enzymes that modulate diverse physiological processes during embryonic development and in adult life. Their deregulations have been implicated in the growth and progression of many cancer types. To date, comparatively little is known about the roles of these molecules during oral carcinogenesis. The aim of this study was to investigate the expression patterns of heparanase and COX-2 during progression of oral epithelial dysplasia (OED) to carcinoma. In situ hybridization and immunohistochemistry were performed on 5 cases of normal mucosa, 15 cases of OED, 5 cases of carcinoma in situ and/or microinvasive carcinoma, and 40 cases of oral squamous cell carcinoma (OSCC). Results demonstrated that heparanase and COX-2 messenger RNA and protein were absent in normal oral mucosa but were coexpressed in increasing intensity as OED progressed to OSCC. Concomitant heparanase- and COX-2-positive staining in the stromal cells suggests that OED/OSCC progression may be modulated by stromal-cancer cell interactions. Diffuse intense staining of poorly differentiated OSCC compared with staining localized to tumor nest periphery in well- and moderately differentiated OSCC suggests that heparanase and COX-2 overexpressions correlated with tumor grade. Strong expression of these enzymes in tumor cells at the advancing front suggests a role in local tumor spread. These results, taken together, suggest that heparanase and COX-2 might play complementary roles in the stepwise progression of OED to carcinoma.

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. Six commercially available collagenous (Bio-Gide [BG], Tissue Fleece [TFL] TissueFoil E forte [TFO], Lycoll [LC], Surgicoll [SG] and Tutodent [TU]) and two noncollagenous (Tabotamp [TA] and Gelita-Tampon [GT]) membranes (size 2 × 2 cm each) were implanted in unconnected subcutaneous pouches in the monkey's back and wounds were allowed to heal by primary intention. The total sample size for each membrane was six. Two monkeys were sacrificed for each experimental period of 4, 14 and 28 days. Explanted specimens were prepared for histologic and histomorphometric analysis. Digitized images of implant sites were systematically sampled using an Image Analyzer with a grid containing 35 intersection points. Four parameters were quantified: membrane degradation, foreign body reaction, tissue organization and vascularization. RESULTS: biodegradation rate and vascularization scored higher in collagenous than in noncollagenous membranes. Except for TFL and TU, the remaining six membranes showed a moderately intense foreign body reaction at week 2. Tissue organization was initiated early in four out of six collagenous (TFL>LC>SG>TFO>BG>TU) compared with one of two noncollagenous (TA>GT) membranes. CONCLUSIONS: the results suggest that differences in membrane structure and composition underlie their different cellular reactions and degradation characteristics.

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. Notch has been detected in the plexiform and follicular ameloblastoma. Its activity in the desmoplastic ameloblastoma is unknown. METHOD: Notch1-4 and their ligands (Jagged1, Jagged2 and Delta1) were examined immunohistochemically in 10 cases of desmoplastic ameloblastoma. RESULTS: Ameloblastoma tumor epithelium demonstrated positive expression for Notch1 (n = 5/10), Notch3 (n = 8/10), Notch4 (n = 10/10), Jagged1 (n = 6/10) and Delta1 (n = 5/10), but no reactivity for Notch2 (n = 10/10) and Jagged2 (10/10). Expression patterns were distinct with some overlap. Positive activity was detected largely in the cell membrane and cytoplasm of peripheral and central neoplastic epithelial cells, and sometimes in the nucleus. Staining score was highest for Notch4. Stromal components namely endothelial cells and fibroblasts showed overexpression for Notch4 but were mildly or non-reactive for the other Notch members and their ligands. CONCLUSIONS: These findings suggest that Notch receptors and their ligands may play differing roles during the development of the desmoplastic ameloblastoma with Notch4 probably playing a greater role in the acquisition of tissue-specific cellular characteristics in the desmoplastic ameloblastoma.

Angiogenic squamous dysplasia-like phenomenon in oral epithelial precursor lesions.

STATEMENT OF THE PROBLEM: Dysplasia, the morphological yardstick of epithelial precursor lesions, is the collective term for a variety of architectural and cytological changes within the altered oral epithelium. Angiogenic squamous dysplasia (ASD), a distinct morphological characteristic in pre-invasive bronchial lesions, describes the presence of capillary tufts that are closely juxtaposed to and projecting into the dysplastic bronchial epithelium. OBJECTIVE: To determine whether ASD-like phenomenon occurs in oral epithelial precursor lesions, and to speculate on its relevance. METHODS: Twenty cases each of mild, moderate and severe oral dysplasia (inclusive of carcinoma-in-situ), and 10 normal oral mucosa (normal controls) were serial sectioned for H and E staining, and for microvessel density (MVD) scoring with CD31, CD34 and CD105. Microcapillary pattern images were digitally captured for 3-D reconstruction. RESULTS: Oral ASD foci consisting of CD31- and CD34-positive capillary loops abutting onto the overlying dysplastic oral epithelium (and causing it to assume an irregular or papillary surface configuration) were identified in moderate (3/20; 15%) and severe dysplasia (13/20; 65%), but not in normal oral mucosa and mild dysplasia. MVD score demonstrated increasing vascularity as epithelium progressed from normal to severe dysplasia (p<0.05). CD105 demonstrated increase neovascularization in all dysplasia grades (p<0.05). CONCLUSIONS: These preliminary findings taken together suggest that: 1. ASD-like phenomenon may be an important intermediary biomarker in oral precursor lesions; and 2. architectural alterations of the entire disturbed mucosa may be a more useful pre-malignancy index.

Influence of abutment design on clinical status of peri-implant tissues.

OBJECTIVE: To compare the clinical soft tissue responses around implant tooth-supported 3-unit bridges using tapered abutments with those using butt-joint abutments. METHODS: In a split-mouth design study, 8 mm Ankylos (Dentsply Friadent, Germany) implants were placed in the second mandibular molar region of 8 adult Macaca fascicularis monkeys about 1 month after extraction of all mandibular molars. After 3 months of submerged healing, 3-unit metal bridges were constructed. Clinical data was collected by the author who was blind to the abutment selections. Implants were clinically evaluated using Waite plaque index, sulcus bleeding index, probing pocket depth (PPD), probing attachment loss (PAL), and width of keratinized mucosa at baseline (BL) and 3-month and 6-month intervals. Stability of the implant was assessed using Periotest device at BL and after 6 months. RESULTS: At BL, all the clinical variables did not differ statistically between the tapered and the butt-joint groups except for PPD (P < 0.05), where the mean PPD was greater in the butt-joint group (2.75 ± 1.02 mm) as compared with the tapered group (1.97 ± 0.65 mm). At the 3-month assessment, there was no difference in all clinical variables. After 6-month loading, no significant difference between these 2 groups was detected in all these variables, with the exception of PAL (P = 0.05) where mean PAL was greater for implants with the butt-joint abutments (0.91 ± 0.86 mm) in comparison with the tapered abutments (0.50 ± 0.88 mm), and mean Periotest values (PTVs) that indicate the tapered-abutment implants (PTV = -4.5 ± 1.60) were more stable than butt-joint-abutment implants (PTV = -1.5 ± 3.59) with P < 0.05. CONCLUSIONS: The differences in these mucogingival responses between these 2 groups at BL (during seating of abutments, especially of butt-joint abutments) and after 6-month loading indicated enhanced peri-implant soft tissue stability around the tapered abutments of this system. There was also enhanced-PTV in the test group for clinical mobility assessment after 6-month loading.