Genomic copy number alterations of primary and secondary metastasizing pleomorphic adenomas

AIMS

Metastasizing pleomorphic adenoma (MPA) is a rare tumour, and its mechanism of metastasis still is unknown. To date, there has been no study on MPA genomics. We analysed primary and secondary MPAs with array comparative genomic hybridization to identify somatic copy number alterations and affected genes.

METHODS AND RESULTS

Tumour DNA samples from primary (parotid salivary gland) and secondary (scalp skin) MPAs were subjected to array comparative genomic hybridization investigation, and the data were analysed with NEXUS COPY NUMBER DISCOVERY. The primary MPA showed copy number losses affecting 3p22.2p14.3 and 19p13.3p123, and a complex pattern of four different deletions at chromosome 6. The 3p deletion encompassed several genes: CTNNB1, SETD2, BAP1, and PBRM1, among others. The secondary MPA showed a genomic profile similar to that of the primary MPA, with acquisition of additional copy number changes affecting 9p24.3p13.1 (loss), 19q11q13.43 (gain), and 22q11.1q13.33 (gain).

CONCLUSION

Our findings indicated a clonal origin of the secondary MPA, as both tumours shared a common profile of genomic copy number alterations. Furthermore, we were able to detect in the primary tumour a specific pattern of copy number alterations that could explain the metastasizing characteristic, whereas the secondary MPA showed a more unbalanced genome.

Abstract 4998: In-depth analysis of myoma organotypic model can determine potential markers of oral cancer invasion

Oral squamous cell carcinoma (OSCC) is the eighth most prevalent malignant neoplasm and accounts for 2% of all deaths by cancer worldwide. OSCCs have a highly variable clinical course, and because it is often diagnosed only after it has reached an advanced stage, the overall survival rate is less than 50% in 5 years. A better knowledge of the mechanisms that influence OSCC development and its progression is still needed. Particularly, most of the attention has been driven to mechanisms associated with tumor cell invasion and how the surrounding tumoral stroma may influence it. The myoma organotypic model is a novel fully human organotypic invasion model that mimics the tumor microenvironment (TME) (Nurmenniemi et al. 2009). Aiming to investigate the molecular mechanisms related to OSCC development and search for prognostic markers for this tumor, we used the myoma organotypic assay, followed by MS-ESI technique of laser microdissected invaded tissue, to analyze several features related to OSCC invasive vs. non-invasive cells. Our results showed that the HSC-3, an aggressive and invasive oral squamous cell carcinoma cell line, invaded as small islands and cell chords and penetrated deeply in the tissue. Unlike, the less aggressive LN2 cells, formed a well structured epithelium layer, but they invaded less in myoma. The proteomic analysis was able to characterize the differential expressed proteins of these, and revealed a group of proteins exclusively expressed in the cells that deeply invade the myoma, such as HMGA2 (high mobility group), JUP (junction plakoglobin), PLEC (plectin), HIST1H2B (Histone H2B), IQGAP1 (Ras GTPase-activating-like protein), EEF1A1 (elongation factor 1-alpha), HSPA9 (Stress-70 protein, mitochondrial), HADHA (Trifunctional enzyme subunit alpha). Additionally, the TME is a unique ambient created and shaped by the tumor, which orchestrates molecular and cellular events taking place in surrounding tissues. Interestingly, we found a group of high abundant proteins expressed in the TME surrounding the invasive island. Among them are PALLD (palladin), TNC (tenascin C), LMNA (laminin), VIM (vimentin), and COL1A (collagen-type I-alpha I), which have been described to be involved in cell migration and proliferation. Our preliminary data suggests that the myoma organotypic tumor invasion assay is successful in determining new molecules and potential pathways associated with OSCC tumor invasion. We also present here a new insight for head and neck cancer biomarkers research that can, ultimately, contribute to more individualized treatment of patients affected by OSCC. However, validation of such results in clinical sample cohorts is important for a better understanding of the biological events associate with tumor invasion and disease spread (metastasis) in those patients.

Citation Format: Nilva K. Cervigne, Carolina Bitu, Bianca A. Pauletti, Adriana F. Paes Leme, Tuula Salo, Ricardo Della Coletta. In-depth analysis of myoma organotypic model can determine potential markers of oral cancer invasion. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4998. doi:10.1158/1538-7445.AM2014-4998

Clinicopathological and immunohistochemical evaluation of oral and oropharyngeal squamous cell carcinoma in Chilean population

In oral and oropharyngeal squamous cell carcinoma (OCSCC and OPSCC) exist an association between clinical and histopathological parameters with cell proliferation, basal lamina, connective tissue degradation and surrounding stroma markers. We evaluated these associations in Chilean patients. A convenience sample of 37 cases of OCSCC (n=16) and OPSCC (n=21) was analyzed clinically (TNM, clinical stage) and histologically (WHO grade of differentiation, pattern of tumor invasion). We assessed the expression of p53, Ki67, HOXA1, HOXB7, type IV collagen (ColIV) and carcinoma-associated fibroblast (α-SMA-positive cells). Additionally we conducted a univariate/bivariate analysis to assess the relationship of these variables with survival rates. Males were mostly affected (56.2% OCSCC, 76.2% OPSCC). Patients were mainly diagnosed at III/IV clinical stages (68.8% OCSCC, 90.5% OPSCC) with a predominantly infiltrative pattern invasion (62.9% OCSCC, 57.1% OPSCC). Significant association between regional lymph nodes (N) and clinical stage with OCSCC-HOXB7 expression (Chi-Square test P < 0.05) was observed. In OPSCC a statistically significant association exists between p53, Ki67 with gender (Chi-Square test P < 0.05). In OCSCC and OPSCC was statistically significant association between ki67 with HOXA1, HOXB7, and between these last two antigens (Pearson's Correlation test P < 0.05). Furthermore OPSCC-p53 showed significant correlation when it was compared with α-SMA (Kendall's Tau-c test P < 0.05). Only OCSCC-pattern invasion and OPSCC-primary tumor (T) pattern resulted associated with survival at the end of the follow up period (Chi-Square Likelihood Ratio, P < 0.05). Clinical, histological and immunohistochemical features are similar to seen in other countries. Cancer proliferation markers were associated strongly from each other. Our sample highlights prognostic value of T and pattern of invasion, but the conclusions may be limited and should be considered with caution (small sample). Many cases were diagnosed in the advanced stages of the disease, which suggests that the diagnosis of OCSCC and OPSCC is made late.

Stromal myofibroblasts in squamous cell carcinoma of the tongue in young patients - a multicenter collaborative study

OBJECTIVE

The purpose of this study was to evaluate the presence of myofibroblasts, frequently associated with a more aggressive neoplastic behavior, in oral tongue squamous cell carcinoma (TSCC) of young patients and to compare with the distribution observed in older patients.

STUDY DESIGN

Tumor samples from 29 patients younger than 40 years old affected by TSCC were retrieved and investigated for the presence of stromal myofibroblasts by immunohistochemical reactions against α smooth muscle actin, and the results obtained were compared to TSCC cases affecting older patients.

RESULTS

No positive reaction could be found in the stromal areas devoid of neoplastic tissue, whereas myofibroblasts were present in 58.6% of the lesions in young patients and in 75.9% of the older ones. No significant difference was found when comparing the invasive front and the overall stroma of both groups, and no correlation could be obtained with stromal α smooth muscle actin expression, higher tumor grades or clinical stage (P > .05).

CONCLUSION

There was no significant difference between the presence of stromal myofibroblasts of TSCC affecting young and old individuals.

Clinical and radiographic features of Hutchinson-Gilford progeria syndrome: A case report

Hutchinson-Gilford progeria syndrome (HGPS) is a rare dysmorphic syndrome characterized by several features of premature aging with clinical involvement of the skin, bones, and cardiovascular system. HGPS has an estimated incidence of one in four million to one in eight million births. The main clinical features of HGPS include short stature, craniofacial dimorphism, alopecia, bone fragility, and cardiovascular disorders. The most frequent cause of death is myocardial infarction at a mean age of 13 years old. Dental manifestations include delayed development and eruption of teeth, discoloration, crowding and rotation of teeth, and displaced teeth. Cone beam computed tomography images revealed the absence of the sphenoid, frontal, and maxillary sinus, flattening of the condyles and glenoid fossa, and bilateral hypoplasia of the mandibular condyles. The disease is caused by mutations in lamin A/C (LMNA). Here, we present a case report of an 11-year-old boy with classical features of HGPS, which was caused by a de novo germ-line mutation (C1824T, G608G) in exon 11 of the LMNA gene. Some uncommon HGPS-associated features in our patient, such as alterations in the facial sinuses and hypoplasia of the condyles, contributed to the expansion of the phenotypic spectrum of this syndrome from a dentomaxillofacial perspective.

Clinicopathological prognostic factors of oral tongue squamous cell carcinoma: a retrospective study of 202 cases

Although several histopathological parameters and grading systems have been described as predictive of the treatment response and outcome of oral squamous cell carcinoma (OSCC), none is universally accepted. A new scoring system, the histological risk model, was recently described to be a powerful predictive tool for recurrence and overall survival in OSCC. The aim of this study was to verify the predictive role of the histological risk model in a cohort of 202 patients at all stages of oral/mobile tongue squamous cell carcinoma (OTSCC). Demographic and clinical data were collected from the medical records and the tumours were evaluated using the histological risk model. Statistical analyses were performed using the χ(2) test, the Kaplan-Meier method, and the Cox regression model. The histological risk model showed no statistical correlation with demographic or clinical parameters and did not Predict the outcome of the OTSCC patients. However, multivariate regression analysis revealed a significant correlation of the clinical disease stage with the disease outcome. Despite major efforts to identify new predictive parameters and histological systems, clinical features are still the most reliable prognostic factors for patients with OTSCC.

Low-level laser therapy promotes proliferation and invasion of oral squamous cell carcinoma cells

Low-level laser therapy (LLLT) has been shown to be effective in promoting cell proliferation. There is speculation that the biostimulatory effect of LLLT causes undesirable enhancement of tumor growth in neoplastic diseases since malignant cells are more susceptible to proliferative stimuli. This study evaluated the effects of LLLT on proliferation, invasion, and expression of cyclin D1, E-cadherin, β-catenin, and MMP-9 in a tongue squamous carcinoma cell line (SCC25). Cells were irradiated with a diode laser (660 nm) using two energy densities (0.5 and 1.0 J/cm(2)). The proliferative potential was assessed by cell growth curves and cell cycle analysis, whereas the invasion of cells was evaluated using a Matrigel cell invasion assay. Expression of cyclin D1, E-cadherin, β-catenin, and MMP-9 was analyzed by immunofluorescence and flow cytometry and associated with the biological activities studied. LLLT induced significantly the proliferation of SCC25 cells at 1.0 J/cm(2), which was accomplished by an increase in the expression of cyclin D1 and nuclear β-catenin. At 1.0 J/cm(2), LLLT significantly reduced E-cadherin and induced MMP-9 expression, promoting SCC25 invasion. The results of this study demonstrated that LLLT exerts a stimulatory effect on proliferation and invasion of SCC25 cells, which was associated with alterations on expression of proteins studied.

ADAM17 mediates OSCC development in an orthotopic murine model

BACKGROUND

ADAM17 is one of the main sheddases of the cells and it is responsible for the cleavage and the release of ectodomains of important signaling molecules, such as EGFR ligands. Despite the known crosstalk between ADAM17 and EGFR, which has been considered a promising targeted therapy in oral squamous cell carcinoma (OSCC), the role of ADAM17 in OSCC development is not clear.

METHOD

In this study the effect of overexpressing ADAM17 in cell migration, viability, adhesion and proliferation was comprehensively appraised in vitro. In addition, the tumor size, tumor proliferative activity, tumor collagenase activity and MS-based proteomics of tumor tissues have been evaluated by injecting tumorigenic squamous carcinoma cells (SCC-9) overexpressing ADAM17 in immunodeficient mice.

RESULTS

The proteomic analysis has effectively identified a total of 2,194 proteins in control and tumor tissues. Among these, 110 proteins have been down-regulated and 90 have been up-regulated in tumor tissues. Biological network analysis has uncovered that overexpression of ADAM17 regulates Erk pathway in OSCC and further indicates proteins regulated by the overexpression of ADAM17 in the respective pathway. These results are also supported by the evidences of higher viability, migration, adhesion and proliferation in SCC-9 or A431 cells in vitro along with the increase of tumor size and proliferative activity and higher tissue collagenase activity as an outcome of ADAM17 overexpression.

CONCLUSION

These findings contribute to understand the role of ADAM17 in oral cancer development and as a potential therapeutic target in oral cancer. In addition, our study also provides the basis for the development of novel and refined OSCC-targeting approaches.

Non-syndromic oral clefts and risk of cancer: a systematic review

Objective: To discuss the risk of cancer among relatives of individuals with cleft lip and palate (CL/P), as well as the risk of CL/P among relatives of individuals with cancer, since studies published currently have suggested  an increased risk of cancer among relatives of cleft individuals. Design: A systematic literature review was carried out in accordance with the Cochrane Collaboration Group protocol, including literature search strategy, selection of papers through the inclusion and exclusion criteria, data extraction and quality assessment. PubMed, Scopus and ISI - Web of Science databases were systematically searched using the fallowing search strings: “cleft lip and palate” AND “cancer”, “oral clefts” AND “cancer” and “orofacial clefts” AND “cancer”. Results: From 653 studies accessed, 8 comprised the final sample: 6 investigating CL/P index cases and their family history of cancer and 2 investigating individuals with cancer and their family history for CL/P. The sample sizes were not homogeneous. Oral clefts, the type of cancer and the degree of kinship family were not categorized in all studies. Leukemia, breast cancer and colon cancer were the most cited types, even as first-and-second degree relatives. Conclusions: An increased risk of cancer among relatives of cleft individuals could not be entirely confirmed. However, studies with this specific purpose suggest that first-and-second degrees relatives of cleft individuals have some types of cancer more often than unexposed families, highlighting that future studies should expand their samples to investigate possible common molecular mechanisms that allow relating oral clefts and cancer.

Immunohistochemical features of multifocal melanoacanthoma in the hard palate: a case report

BACKGROUND

Melanoacanthoma (MA) has been described in the oral mucosa as a solitary lesion or, occasionally, as multiple lesions. MA mainly affects dark skinned patients and grows rapidly, showing a plane or slightly raised appearance and a brown to black color. The differential diagnosis includes oral nevi, amalgam tattoos, and melanomas. We report here the case of a 58-year-old black woman who presented multiple pigmented lesions on the hard palate.

CASE PRESENTATION

Based on the differential diagnosis of melanoma, a punch biopsy (4 mm in diameter) was performed. The material was fixed in 10% formalin, embedded in paraffin, and stained with hematoxylin-eosin or submitted to immunohistochemical analysis. Immunohistochemistry using antibodies against protein S-100, melan-A, HMB-45, MCM-2, MCM-5, Ki-67 and geminin was performed. Immunohistochemical analysis revealed strong cytoplasmic immunoreactivity of dendritic melanocytes for proteinS-100, HMB-45 and melan-A.Positive staining for proliferative markers (MCM-2, MCM-5, Ki-67) was only observed in basal and suprabasal epithelial cells, confirming the reactive etiology of the lesion. The diagnosis was oral Melanoacanthoma (MA).

CONCLUSION

The patient has been followed up for 30 months and shows no clinical alterations. MA should be included in the differential diagnosis of pigmented lesions of the oral cavity.

The fatty acid synthase inhibitor orlistat reduces experimental metastases and angiogenesis in B16-F10 melanomas

BACKGROUND

Fatty acid synthase (FASN) is overexpressed and associated with poor prognosis in several human cancers. Here, we investigate the effect of FASN inhibitors on the metastatic spread and angiogenesis in experimental melanomas and cultured melanoma cells.

METHODS

The lung colonisation assay and cutaneous melanomas were performed by the inoculation of mouse melanoma B16-F10 cells in C57BL6 mice. Blood vessel endothelial cells (RAEC and HUVEC) were applied to determine cell proliferation, apoptosis, and the formation of capillary-like structures. Vascular endothelial growth factor A (VEGFA) expression was evaluated by quantitative RT-PCR and ELISA in B16-F10, human melanoma (SK-MEL-25), and human oral squamous carcinoma (SCC-9) cells. Conditioned media from these cancer cell lines were used to study the effects of FASN inhibitors on endothelial cells.

RESULTS

B16-F10 melanoma-induced metastases and angiogenesis were significantly reduced in orlistat-treated mice. Fatty acid synthase inhibitors reduced the viability, proliferation, and the formation of capillary-like structures by RAEC cells, as well as the tumour cell-mediated formation of HUVEC capillary-like structures. Cerulenin and orlistat stimulated the production of total VEGFA in B16-F10, SK-MEL-25, and SCC-9 cells. Both drugs also enhanced VEGFA(121), (165), (189,) and (165b) in SK-MEL-25 and SCC-9 cells.

CONCLUSION

FASN inhibitors reduce metastasis and tumour-induced angiogenesis in experimental melanomas, and differentially modulate VEGFA expression in B16-F10 cells.

Increased number of Langerhans cells in oral lichen planus and oral lichenoid lesions

OBJECTIVE

The aim of this study was to quantify the presence of Langerhans cells (LC) in oral lichen planus (OLP) and oral lichenoid lesions (OLL), comparing them with normal epithelium.

STUDY DESIGN

Thirty-six patients with biopsy-proven OLP or OLL were selected for the study, as well as 23 control subjects free of inflammatory conditions. Immunohistochemical reactions were performed using the streptavidin-biotin peroxidase complex method with CD1a and CD83 primary antibodies. Densities were compared between groups and correlated with microscopic findings.

RESULTS

Patients with lichenoid conditions (OLP + OLL) presented higher densities of CD1a(+) cells than the control subjects (P = .03). Higher densities of CD1a were associated with a thinner layer of inflammatory cells (P = .02).

CONCLUSIONS

This study indicates that OLP and OLL are characterized by the recruitment of LC, which may play a significant role on its pathogenesis.

Cleidocranial dysplasia: oral features and genetic analysis of 11 patients

BACKGROUND

Cleidocranial dysplasia (CCD) is a dominantly inherited autosomal disease characterized by typical bone defects including short stature, persistently open or delayed closure of the cranial sutures, and hypoplastic or aplastic clavicles. Oral features are frequent and include supernumerary teeth, delayed eruption or impaction of the permanent teeth, and malocclusion. Heterozygous mutations in RUNX2 gene, which encodes a transcription factor essential for osteoblast differentiation, were identified as the etiological cause of CCD.

OBJECTIVE AND METHODS

Herein, we performed physical and radiographic examination and screening for RUNX2 mutations in 11 patients from five families with CCD.

RESULTS

All patients demonstrated the classical phenotypes related to CCD. Families whose affected members had several dental alterations such as multiple impacted and supernumerary teeth demonstrated heterozygous missense mutations (R190Q and R225Q) that impair the runt domain of RUNX2. On the other hand, CCD patients from families with low frequency of dental abnormalities showed no mutation in RUNX2 or mutation outside of the runt domain (Q292fs→X299).

CONCLUSION

The current findings suggest a correlation between dental alterations and mutations in the runt domain of RUNX2 in CCD patients. Further clinical and genetic studies are needed to clarify the relationship between phenotypes and genotypes in CCD and to identify other factors that might influence the clinical features of this uncommon disease.

Sclerotherapy followed by surgery for the treatment of oral hemangioma: a report of two cases

Hemangiomas, vascular malformations, and varices are common benign vascular lesions in the head and neck region. They can occur in the mouth and primarily affect the lips, tongue, buccal mucosa, and palate. The main types of treatments are surgery and intralesional injection of sclerosant agents. However, other therapies have been considered, such as systemic corticosteroids, laser therapy, interferon a, and cryotherapy. Currently, sclerotherapy is employed largely because of its efficiency and ability to conserve the surrounded tissues. Surgery can be used exclusively or associated with sclerotherapy in lesions that do not show complete resolution. This article describes the cases of two patients with oral hemangiomas that were submitted to sclerotherapy with ethanolamine oleate. Although an important decrease was detected after seven applications in both cases, surgical resection of the residual lesion was performed to achieve optimal results.

Impact of smoking on inflammation: overview of molecular mechanisms

BACKGROUND

Inflammation is a critical component of normal tissue repair, as well as being fundamental to the body's defense against infection. Environmental factors, such as smoking, have been reported to modify the host response and hence modify inflammation progression, severity and outcome. Therefore, a comprehensive understanding of the molecular mechanisms by which smoking affects inflammation is vital for preventive and therapeutic strategies on a clinical level.

AIM

The purpose of the present article is to review the potential biological mechanisms by which smoking affects inflammation, emphasizing recent developments.

RESULTS

Smoking is reported to effect a number of biological mediators of inflammation through its effect on immune-inflammatory cells, leading to an immunosuppressant state. Recent evidence strongly suggests that the molecular mechanisms behind the modulation of inflammation by smoking mainly involve the nuclear factor-kappa B (NF-kB) family, through the activation of both an inhibitor of IkB kinase (IKK)-dependent and -independent pathway. In addition to NF-kB activation, a number of transcriptional factors including GATA, PAX5 and Smad 3/4, have also been implicated.

CONCLUSION

Multiple mechanisms may be responsible for the association of smoking and inflammation, and the identification of potential therapeutic targets should guide future research.

Imaging evalution of the gingival fibromatosis and dental abnormalities syndrome

OBJECTIVE

The purpose of this study was to evaluate the dentomaxillofacial imaging features of one family affected by the gingival fibromatosis (GF) and dental abnormalities (DA) syndrome.

METHODS

Conventional radiographs (periapical and panoramic) and cone beam CT (CBCT) were performed in nine members of this family: four were affected by the syndrome and five were not.

RESULTS

The four affected members demonstrated mild generalized GF in association with DA, including hypoplastic amelogenesis imperfecta, intrapulpal calcifications, delay on tooth eruption and pericoronal radiolucencies in unerupted teeth. None of these oral changes were identified in the five unaffected members. All nine members presented alterations in the paranasal sinuses and mucosal thickening of the maxillary sinus was the most common finding.

CONCLUSION

Family members not affected by the syndrome showed similar alterations in the paranasal sinuses and CBCT was useful to characterize the dentomaxillofacial features of this new syndrome associating GF and DA.

Impact of smoking on inflammation: overview of molecular mechanisms

BACKGROUND

Inflammation is a critical component of normal tissue repair, as well as being fundamental to the body's defense against infection. Environmental factors, such as smoking, have been reported to modify the host response and hence modify inflammation progression, severity and outcome. Therefore, a comprehensive understanding of the molecular mechanisms by which smoking affects inflammation is vital for preventive and therapeutic strategies on a clinical level.

AIM

The purpose of the present article is to review the potential biological mechanisms by which smoking affects inflammation, emphasizing recent developments.

RESULTS

Smoking is reported to effect a number of biological mediators of inflammation through its effect on immune-inflammatory cells, leading to an immunosuppressant state. Recent evidence strongly suggests that the molecular mechanisms behind the modulation of inflammation by smoking mainly involve the nuclear factor-kappa B (NF-kB) family, through the activation of both an inhibitor of IkB kinase (IKK)-dependent and -independent pathway. In addition to NF-kB activation, a number of transcriptional factors including GATA, PAX5 and Smad 3/4, have also been implicated.

CONCLUSION

Multiple mechanisms may be responsible for the association of smoking and inflammation, and the identification of potential therapeutic targets should guide future research.

Cyclosporin A-induced gingival overgrowth is not associated with myofibroblast transdifferentiation

Cyclosporin A (CyA) induces gingival overgrowth via its stimulatory effects on expression of transforming growth factor-beta1 (TGF-beta1) and collagen. It is not known whether CyA has a direct effect on gingival fibroblasts or induces its effect indirectly via stimulation of myofibroblast transdifferentiation. The present study was undertaken to examine the in vivo and in vitro effect of CyA on myofibroblast transdifferentiation. Rats were treated for 60 days with a daily subcutaneous injection of CyA, and the gingival overgrowth tissue was analyzed by immunohistochemistry. In vitro, fibroblasts from normal gingiva (NG) were cultured in the presence of different concentrations of CyA, and subjected to semi-quantitative reverse transcriptase-polymerase chain reaction and western blot. Although CyA treatment stimulated TGF-beta1 expression by NG fibroblasts, it lacked to induce expression and production of isoform alpha of smooth muscle actin (alpha-SMA), the specific myofibroblast marker. The expression levels of connective tissue growth factor (CTGF), which has been considered a key molecule to promote the transdifferentiation of myofibroblasts via TGF-beta1 activation, were unaffected by CyA. Our results demonstrate that CyA-induced gingival overgrowth is not associated with activation of myofibroblast transdifferentiation, since CyA is not capable to increase CTGF expression.

Immunohistochemical study of androgen, estrogen and progesterone receptors in salivary gland tumors

The aim of this work was to study the immunohistochemical expression of androgen receptor, estrogen receptor and progesterone receptor in pleomorphic adenomas, Warthin's tumors, mucoepidermoid carcinomas and adenoid cystic carcinomas of salivary glands. A total of 41 pleomorphic adenomas, 30 Warthin's tumors, 30 mucoepidermoid carcinomas and 30 adenoid cystic carcinomas were analyzed, and the immunohistochemical expression of these hormone receptors were assessed. It was observed that all cases were negative for estrogen and progesterone receptors. Androgen receptor was positive in 2 cases each of pleomorphic adenoma, mucoepidermoid carcinoma and adenoid cystic carcinoma. In conclusion, the results do not support a role of estrogen and progesterone in the tumorigenesis of pleomorphic adenomas, Warthin's tumors, mucoepidermoid carcinomas and adenoid cystic carcinomas. However, androgen receptors can play a role in a small set of salivary gland tumors, and this would deserve further studies.

Idiopathic gingival fibromatosis: description of two cases

Gingival fibromatosis is an enlargement localized or generalized of the gingival tissue characterized by an expansion and accumulation of the connective tissue, predominantly type I collagen, with occasional presence of increased number of cells, supposed fibroblastic proliferation. Gingival fibromatosis can be induced as a side effect of systemic drugs, such as phenytoin, cyclosporin, and nifedipine, or due to hereditary factors. However, in some cases, the gingival overgrowth is idiopathic. This paper reports two cases of idiopathic gingival fibromatosis and discusses the diagnosis, histopathological features, treatment and immunohistochemical evaluation of myofibroblasts of this condition. The tissues removed were fixed in formalin, and sections used for hematoxylin and eosin and Masson tricromic stain. To determine the presence of myofibroblasts, we performed immunohistochemistry against a-SMA protein. Histological examination revealed epithelial hyperplasia with long rete pegs and increase in the dense fibrous connective tissue. The Masson tricromic stain revealed wide bundles of collagen strongly stained. It was showed negative labeling to a-SMA. These results strongly suggest that myofibroblasts are not involved in gingival overgrowth in the cases of IGF reported. Future studies will be necessary to determine the pathogenesis of idiopathic gingival fibromatosis.

Expression of Six1 homeobox gene during development of the mouse submandibular salivary gland

BACKGROUND

Members of the Six family of homeoproteins are expressed in numerous tissues during vertebrate embryogenesis, and are critical regulators of both cell proliferation and survival. Here we report the temporal and spatial expression of Six1 during maturation of the mouse submandibular salivary gland (SSG) from embryonic day 18.5 (E18.5) to postnatal day 28. Additionally, we examine the role of Six1 during SSG development using Six1-deficient mice.

METHODS

Six1 expression was assessed by reverse transcription-polymerase chain reaction, Western blot, and immunofluorescence. Proliferation was measured by bromodeoxyuridine (BrdU) incorporation index, and apoptosis was evaluated by TUNEL assay.

RESULTS

Six1 mRNA and protein levels are high in the epithelial SSG cells at E18.5 and decrease progressively in the postnatal maturing SSG. Although SSGs from Six1(-/-) embryos are significantly smaller than wild type SSGs, the histological structures of the SSG acini and ducts are similar. Six1(-/-) salivary epithelial cells exhibit an intrinsic defect in cell proliferation accompanied by a significant reduction in the Six1 target gene cyclin A1, previously shown to be a critical mediator of Six1-induced proliferation.

CONCLUSION

Our results suggest that the reduction in size of Six1(-/-) SSGs is result of a decrease in cell proliferation during development/maturation.

Comparative clinicopathological study of intraoral sebaceous hyperplasia and sebaceous adenoma

OBJECTIVE

The objective of this study was to compare the clinicopathological features of oral sebaceous hyperplasia and sebaceous adenoma.

STUDY DESIGN

Clinical data, microscopical characteristics, and ki-67 immunoexpression were comparatively analyzed on 2 intraoral sebaceous adenomas, 6 intraoral sebaceous hyperplasias, and 21 normal intraoral sebaceous glands.

RESULTS

Clinically, sebaceous glands presented as multiple separated papules, sebaceous hyperplasias as a single enlarged papule, and sebaceous adenoma as a well-defined nodule. Microscopically, sebaceous adenoma presented an increased number of lobules, smaller lobules, and a greater number of germinative/squamous cells. Sebaceous hyperplasia also had an increased number of lobules and fewer number of germinative/squamous cells, as compared to normal oral sebaceous glands. Ki-67 expression was seen only in germinative cells and counts were higher in sebaceous adenomas followed by hyperplasias and normal glands.

CONCLUSIONS

Sebaceous hyperplasias and adenomas showed different clinical, microscopic, and proliferative characteristics, suggesting the usefulness of the studied criteria on diagnosis of these uncommon oral lesions.

An epidemiologic study of lip and palate clefts from a Brazilian reference hospital

OBJECTIVE

To investigate the distribution of several types of clefts among adolescents and adults receiving treatment at the Center for Rehabilitation of Craniofacial Anomalies, Unifenas, Minas Gerais State, Brazil.

METHODS AND MATERIALS

A total 154 untreated patients of low socioeconomic means with cleft lips and/or palates, without additional malformations, who came to the Center for Rehabilitation of Craniofacial Anomalies for treatment were analyzed, and clinical and socioeconomic variables were detailed.

RESULTS

A predominance of complete cleft lip and palate, either unilateral or bilateral, was observed (52.60%), followed by isolated cleft lip (33.12%) and isolated cleft palate (14.28%). A discrete relationship between cleft palate and the female gender was noticed, and males were more affected by other types of clefts.

CONCLUSIONS

Non-Caucasian males with unilateral complete cleft lip and palate constituted the main profile of affected individuals.

Prevalence of nonsyndromic oral clefts in a reference hospital in the state of Minas Gerais, Brazil, between 2000-2005

The aim of the present study was to analyze the prevalence of nonsyndromic oral clefts in children receiving treatment at the Center for the Rehabilitation of Craniofacial Anomalies, José do Rosário Vellano University, Alfenas, MG, Brazil. All the data for the epidemiological study was retrieved from the files of 126 pediatric patients with oral clefts without any additional malformation, who came to the center for treatment between 2000 and 2005. A predominance of clefts was observed in Caucasians, and the ratio of male to female was 1.3. Males were 2.57 times more affected by cleft lip and palate (CLP) than females. CLP with a prevalence of 39.68% and isolated cleft lip (CL) with a prevalence of 38.09% were the most common anomalies, followed by isolated cleft palate (CP; 22.23%). Complete and unilateral CLP (26.19%) presented the highest prevalence, followed by incomplete and unilateral CL (23.81%). The present study presents the experience of a reference hospital in the state of Minas Gerais; however, the real prevalence of oral clefts in Brazil is still unknown. Our findings differ from those of a few previous Brazilian reports because they suggest similar prevalences of CLP and CL, and a higher prevalence of CLP in Caucasian males.

Chondrosarcoma involving the periodontum: clinicopathological and immunohistochemical features of a case study

Chondrosarcoma is a rare flat bone neoplasm. Herein, we present the clinicopathological and immunohistochemical findings of a case affecting the periodontum. A 16-year-old girl presented a painless reddish mass in the lower anterior gingiva. Radiographs showed bone affected by vertical and horizontal loss and enlargement of periodontal space. The histopathological features showed atypical cartilage arranged in lobules compatible with chondrosarcoma. Immunohistochemistry showed that tumor cells were immunoreactive for the anti-vimentin and S-100 antibodies. Moreover, no tumor cells had been immunostained by anti-p53. Treatment consisted of chemotherapy, followed by radical surgery and postsurgery treatment with an association of radio and chemotherapy. After one year, no signs of recurrence have been observed.

Hereditary Gingival Fibromatosis: Report of a Five-Generation Family Using Cellular Proliferation Analysis

BACKGROUND

Hereditary gingival fibromatosis (HGF) is an uncommon condition characterized by an accumulation of extracellular matrix resulting in a fibrotic enlargement of the gingiva. The goal of this article is to describe one kindred affected with HGF and discuss the diagnosis, treatment, and control of the disease. The pattern of inheritance, histopathologic characteristics, and proliferative potential of epithelial and mesenchymal cells of HGF are also emphasized.

METHODS

To characterize the pattern of inheritance and the clinical appearance of gingival overgrowth, 117 family members were examined. The recurrence risk was estimated by the use of a genetic analysis program. Immunohistochemistry against the proliferating cell nuclear antigen (PCNA) and pKi-67 was performed to assess cellular proliferation of normal gingiva (NG) and HGF cells.

RESULTS

Examination of the family pedigree demonstrated an autosomal dominant trait of inheritance, and a sibling recurrence risk of 0.085 and an offspring recurrence risk of 0.078, indicating that HGF was a consequence of genetic alteration with low penetrance. Unaffected and affected members transmitted the disease to their offspring. The affected patients showed a generalized but mild gingival overgrowth. Surgical treatment consisted of a combination of gingivectomy and gingivoplasty. Histologic examination showed that the gingival lesions of all patients were quite similar, with increased amounts of collagen fiber bundles in the connective tissue. Immunohistochemistry revealed that the proliferative potential of epithelial cells was significantly higher in the HGF group compared to the NG group, whereas mesenchymal cells from both groups were negative for the proliferative markers.

CONCLUSION

Our data demonstrated that, in the studied family, HGF is transmitted by an autosomal dominant pattern with incomplete disease penetrance, and although the gingival enlargement resulted from an excessive accumulation of collagen fibers, HGF is characterized by an increase in the proliferation rate of epithelial cells.

Parotid mycobacteriosis is frequently caused by Mycobacterium tuberculosis in advanced AIDS

BACKGROUND

Tuberculosis is one of the leading infectious diseases in the world, with more than 2 million new cases annually. It is one of the main causes of death of human immunodeficiency virus (HIV)-positive patients, involving multiple organs and particularly the lungs. Nevertheless there are few consistent studies about tuberculosis involving the parotid of HIV patients. The objective of this work was to describe the histological and immunohistochemical characteristics of 10 cases of mycobacteriosis involving the parotid of autopsied patients with advanced acquired immunodeficiency syndrome (AIDS), including identification of the Mycobacterium species.

METHODS

Detection of 'M. tuberculosis complex' was performed by polymerase chain reaction (PCR) and ligase chain reaction (LCR) and Mycobacterium avium by PCR.

RESULTS

All cases showed involvement of intraparotid lymph nodes, but the glandular parenchyma was affected in only three cases. Most of the cases (80%) presented a chronic non-caseating granulomatous inflammation, and in two cases predominated foamy macrophages, full of bacteria, and no granuloma formation. In areas of mycobacteriosis, macrophages predominated followed by TCD8, B and TCD4 lymphocytes. All cases were infected by Mycobacterium genus and 'M. tuberculosis complex' was detected in five cases by LCR and in eight by PCR, while M. avium was positive in one case only, which was also positive for M. tuberculosis.

CONCLUSIONS

Parotid mycobacteriosis in advanced AIDS is characterized by intraparotid lymph node non-caseating inflammatory granulomatous lesion, caused mainly by M. tuberculosis.

Sialolithiasis of minor salivary glands: a clinical and histopathological study

Sialolithiasis is one of the most common disorders of particular major salivary glands. It is caused by sialolith within the ducts or parenchyma of particularly major salivary glands. Although sialolithasis is not uncommon, it often is clinically misdiagnosed when minor salivary glands are affected. This article describes the clinical and microscopic findings of nine cases of sialolithiasis of minor salivary glands. The lesions frequently appeared as single and asymptomatic nodules in middle-aged patients. Only three sites were affected: four lesions were found in the upper lip, three in the buccal mucosa, and two in the lower lip. The most common clinical hypotheses for diagnosis were mucocele, sialoadenitis, and benign salivary gland tumor. Sialolithiasis of minor salivary glands was misdiagnosed frequently. It should be considered as a possible diagnosis when swelling of the oral tissues is observed.

Peutz-Jeghers syndrome in a 14-year-old boy: case report and review of the literature

Peutz-Jeghers syndrome (PSJ) is a relatively rare but well-recognized condition, with a prevalence of approximately one in 120,000 births in the USA. It is generally inherited as an autosomal dominant trait, although 35% of cases are new mutations. This disorder is characterized by melanocytic macules on the hands, feet, peri-oral skin and oral mucosa, and multiple gastrointestinal hamartomatous polyps. People with PSJ have an increased risk for developing a variety of malignant tumours. The aim of the present study was to report one case of PSJ in a 14-year-old boy with mucocutaneous pigmentation associated with duodenal hamartomatous polyps.

Ovariectomy reduces the gelatinolytic activity and expression of matrix metalloproteinases and collagen in rat molar extraction wounds

Osteoporosis is commonly associated with estrogen deficiency. However, the mechanisms by which the lack of this hormone causes bone loss are poorly understood. The bone structure of the oral cavity seems to be affected by estrogen deficiency, since a delayed healing process after tooth extraction has been observed after ovariectomy in rats. The aim of this study was to describe the effect of the absence of estrogen on the expression and activity of matrix metalloproteinases (MMC)-2 and -9 and expression of types I and III collagens in the alveolar granulation tissue of young female rats after tooth extraction. Sixty-six, four-week-old female rats underwent bilateral ovariectomies (OVX) or sham operations. Three weeks later, both first and second mandibular molars were extracted and the animals were killed by cervical dislocation 3, 5, or 7 days after tooth extraction. The granulation tissues were collected from the extracted alveolar sockets and used for zymographic, Western blot, or reverse transcription polymerase chain reaction (RT-PCR) analysis. There was a gradual increase on the expression of all studied proteins as well as MMP-2 and -9 activities in the periods after surgery. In contrast, OVX animals showed a significant decrease in the gelatinolytic activities and expression of MMP-2 and -9 and types I and III collagens. The results presented here in suggest that the absence of estrogen may possibly contribute to the delayed alveolar wound healing by interfering with the extracellular matrix turnover.

Proliferation of Fibroblasts Cultured From Normal Gingiva and Hereditary Gingival Fibromatosis Is Dependent on Fatty Acid Synthase Activity

BACKGROUND

Fatty acid synthase (FAS) is the enzyme that synthesizes palmitate from malonyl-CoA and acetyl-CoA. Recent studies have shown that FAS is overexpressed in human cancers and that its activity is necessary for cell proliferation. Hereditary gingival fibromatosis (HGF) is a genetic disease manifested as a progressive enlargement of the gingiva. The pathogenesis of this condition is not understood; however, a proliferative advantage of HGF fibroblasts in comparison with cells from normal gingiva (NG) has been described. The aim of this study was to investigate the role of FAS in NG and HGF fibroblast proliferation.

METHODS

NG and HGF fibroblasts had their proliferative potential assessed by automated cell counting and immunocytochemistry against Ki-67 or proliferating cell nuclear antigen (PCNA). The production of FAS, androgen receptor (AR), and ErbB2 was analyzed by Western blot and the pattern of FAS expression studied by immunocytochemistry. FAS activity was blocked by the specific inhibitor cerulenin.

RESULTS

Higher proliferation rates were found in fibroblasts isolated from HGF than from NG. HGF fibroblasts with greater proliferative potential produced more FAS and AR than the cell lines with lower growth rates, and all studied cell lines produced similar amounts of the ErbB2 protein. In addition, the FAS inhibitor cerulenin was able to significantly reduce the proliferation of both NG and HGF cells.

CONCLUSIONS

These results show that FAS is expressed by gingival fibroblasts and that highly proliferative HGF cells produced more FAS and AR than the other fibroblast cell lines. Moreover, FAS inhibition significantly reduced both NG and HGF fibroblast growth, suggesting a role for the androgen-driven fatty acid biosynthesis in their proliferation.

Dental Alterations Associated with X-Linked Hypophosphatemic Rickets

The X-linked hypophosphatemic rickets is a rare metabolic disorder characterized by low serum phosphate levels caused by a decreased renal tubular reabsorption of inorganic phosphates. The initial complaints are a delay in the development of walking caused by deformity of the legs. Oral findings include poorly mineralized dentin, enlarged pulp chambers and root canals, and periradicular abscesses in caries-free teeth. We present three patients from the same family with X-linked hypophosphatemic rickets showing bone and dental alterations.

Cyclosporin A induces proliferation in human gingival fibroblasts via induction of transforming growth factor-beta1

BACKGROUND

Cyclosporin A (CsA) is a widely used immunosuppressant that causes significant side effects including gingival overgrowth. The pathogenesis of this condition is not fully understood; however, recent studies show that CsA regulates the transcription of several cytokines including transforming growth factor-beta 1 (TGF-beta1). In this study, we evaluated the effects of CsA and TGF-beta1 on human normal gingival (NG) fibroblast proliferation, and explored a possible autocrine stimulation of TGF-beta1 as a cellular regulator of proliferation induced by CsA in NG fibroblasts.

METHODS

NG fibroblast cell lines were incubated with increasing concentrations of CsA or TGF-beta1 and the proliferation index determined by automatic cell counting, BrdU incorporation, PCNA expression, and mitotic potential. To determine the effect of TGF-beta1 on the proliferation rate of NG fibroblasts under CsA treatment, NG fibroblast cultures were simultaneously treated with CsA and antisense oligonucleotides against the translation-start site of the TGF-beta1 mRNA.

RESULTS

Treatment of NG fibroblasts with CsA or TGF-beta1 significantly stimulated the cell proliferation in a dose-dependent manner. Furthermore, neutralization of TGF-beta1 production in CsA-treated NG fibroblasts inhibited CsA's effect on NG fibroblast proliferation, demonstrating an autocrine stimulatory effect of TGF-beta1 in CsA-treated NG fibroblast proliferation.

CONCLUSION

The results presented here suggest that CsA stimulatory induction of NG fibroblast proliferation is mediated via TGF-beta1 in an autocrine fashion.

Sebaceous adenoma of oral cavity: report of case and comparative proliferation study with sebaceous gland hyperplasia and Fordyce's granules

Sebaceous adenoma (SA) is a rare solitary tumour with a predilection for the forehead and scalp. In the English literature, less than 10 cases of SA have been described in the oral cavity. The objective of this study was to examine the clinicopathologic features and evaluate the expression of epidermal growth factor and its receptor, estrogen receptor and androgen receptor in SA and in its differential diagnoses including sebaceous gland hyperplasia (SGH) and Fordyce's granules (FG). Additionally, we analysed the proliferative potential of sebaceous cells from SA, SGH and FG by measuring proliferating cell nuclear antigen (PCNA) expression and quantification of argyrophilic nuclear organizer regions (AgNORs). The SA showed many clinicopathologic similarities to cases previously reported including the biphasic population of cells, in the periphery of lobules undifferentiated basaloid cells whereas the central area was formed by mature sebocytes. SA was composed of 198 lobules of sebaceous cells, whereas SGH and FG showed a mean of 21 +/- 7.81 and 5.84 +/- 2.83, respectively. The AgNOR and PCNA indices were similar in SA, SGH and FG. These data suggest that lobule counts may be used as additional criteria in distinguishing SA of the oral cavity from other intraoral sebaceous gland lesions.

Histomorphometric characteristics and expression of epidermal growth factor and its receptor by epithelial cells of normal gingiva and hereditary gingival fibromatosis

OBJECTIVE

The objective of this study was to examine the histomorphometric features and evaluate the expression of epidermal growth factor (EGF) and transmembranic receptor (EGFr) and the proliferative potential of epithelial cells from normal and hereditary gingival fibromatosis (HGF) gingival tissues.

BACKGROUND

EGF is a multifunctional cytokine with a variety of biological effects including stimulation of cell proliferation by binding to its specific EGFr.

METHODS

Immunohistochemistry was performed to measure EGF and EGFr expression and the epithelial cell proliferation was determined by measuring proliferating cell nuclear antigen (PCNA).

RESULTS

Histomorphometric evaluation indicated that in HGF the mean height of the epithelial papillae was higher compared to the normal gingiva (NG), whereas mean epithelial area and number of epithelial papillae were quite similar in both groups. The EGF and EGFr positive cells were observed in the basal, spinous and granular cell layers of both normal and HGF tissues, with a gradual reduction from the basal layer. Although the expressions of EGF and EGFr in the control group were significantly higher than those from HGF, in HGF the epithelial papilla tips showed increased number of proliferating cells and elevated expression of EGF and EGFr. There was a correlation between the proliferative potential of epithelial cells and the expression of EGF or EGFr only in the epithelial papilla tips of HGF gingiva.

CONCLUSION

Our data suggest that EGF and EGFr in the oral epithelium of HGF gingiva may stimulate epithelial cell proliferation, with the resultant apical migration of the oral epithelium and formation of the slender deep epithelial papillae; however, without hyperplastic alterations.

Effect of transforming growth factor-beta1, interleukin-6, and interferon-gamma on the expression of type I collagen, heat shock protein 47, matrix metalloproteinase (MMP)-1 and MMP-2 by fibroblasts from normal gingiva and hereditary gingival fibromatosis

BACKGROUND

Increased collagen and extracellular matrix deposition within the gingiva is the main characteristic feature of hereditary gingival fibromatosis (HGF). To date, it is not well established if these events are a consequence of alterations in the collagen and other extracellular matrix molecules synthesis or disturbances in the homeostatic equilibrium between synthesis and degradation of extracellular matrix molecules. Cytokines are important regulators of expression of the profibrogenic genes, including type I collagen and its molecular chaperone heat shock protein (Hsp)47 and proteolytic enzymes degrading extracellular matrix such as matrix metalloproteinases-1 and -2 (MMP-1 and MMP-2).

METHODS

In this study, we analyzed the expression and production of type I collagen, Hsp47, MMP-1, and MMP-2 in normal gingiva (NG) and HGF fibroblasts, and investigated the effects of transforming growth factor-beta1 (TGF-beta1), interleukin-6 (IL-6) and interferon-gamma (IFN-gamma) on the expression of these genes by NG and HGF fibroblasts.

RESULTS

Our results obtained from semi-quantitative reverse transcription-polymerase chain reactions (RT-PCR), Western blots, enzyme-linked immunosorbent assays (ELISA), and enzymographies clearly demonstrated that the expression and production of type I collagen and Hsp47 were significantly higher in fibroblasts from HGF than from NG, whereas MMP-1 and MMP-2 expression and production were lower in fibroblasts from HGF patients. Addition of TGF-beta1 and IL-6, which are produced in greater amounts by HGF fibroblasts, promoted an increase in type I collagen and Hsp47 and a decrease in MMP-1 and MMP-2 expression. IFN-gamma reduced both type I collagen and Hsp47 expression, whereas it had a slight effect on the expression of MMP-1 and MMP-2.

CONCLUSION

These patterns of expression and production suggest that enhanced TGF-beta1 and IL-6 production simultaneously increase the synthesis and reduce the proteolytic activities of fibroblasts from patients with HGF, which may favor the accumulation of extracellular matrix observed in patients with this condition.

Expression of matrix metalloproteinases in cyclosporin-treated gingival fibroblasts is regulated by transforming growth factor (TGF)-beta1 autocrine stimulation

BACKGROUND

Gingival overgrowth is a common side effect following the administration of cyclosporin A (CsA). The pathogenesis of this condition is not fully understood; however, recent studies show that CsA regulates the transcription of several cytokines including transforming growth factor-beta1 (TGF-beta1). The aim of this study was to investigate the potential role of TGF-beta1 in the pathogenesis of CsA-induced gingival overgrowth, exploring a possible autocrine stimulation of TGF-beta1 as a cellular regulator of synthesis of matrix metalloproteinases (MMPs) and its tissue inhibitors (TIMPs).

METHODS

Gingival fibroblasts from human normal gingiva were incubated with increasing concentrations of CsA, cultured for 24 hours, and the expression and production of TGF-beta1 determined by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. MMP and TIMP mRNA expression levels were also analyzed by RT-PCR. To determine the effect of TGF-beta1 on the expression of MMP and TIMP by human gingival fibroblasts under CsA treatment, human gingival fibroblast cultures were treated with sense oligonucleotides (SON) or antisense oligonucleotides (AON).

RESULTS

CsA simultaneously stimulated TGF-beta1 expression and production and inhibited expression of MMP-1 and MMP-2 by human gingival fibroblasts, whereas CsA has a slight effect on TIMP-1 and TIMP-2 expression. AON reduced TGF-beta1 production as demonstrated by ELISA, whereas TGF-beta1 mRNA expression levels were not significantly modified. The inhibition of TGF-beta1 production by AON modulated MMP expression, demonstrating the autocrine inhibitory effect of TGF-beta1 in CsA-treated human gingival fibroblasts.

CONCLUSIONS

The data presented here suggest that TGF-beta1 in an autocrine fashion may contribute to a reduction of proteolytic activity of human gingival fibroblasts in CsA-induced gingival overgrowth, which favors the accumulation of extracellular matrix.

[Comparison between gingival and periodontal ligament fibroblasts from the same subject]

The objective of this study was to compare fibroblasts from the periodontal ligament (PLF) and gingival fibroblasts (GF) as to morphology, proliferation rate and protein synthesis. PLF and GF were explanted from tissues of the same patient. To characterize and compare the morphology of cells, PLF and GF were plated and analyzed under phase-contrast and optical microscopies. Proliferation rates were determined by means of automated counts carried out in days 1, 4, 7, 15 and 21, and also by means of the bromodeoxyuridine labelling index (BrdU). Total protein content was analyzed by means of electrophoresis in 10% polyacrylamide gel and zimography containing gelatin as substrate. PLF were bigger and more elongated than GF in subconfluence and confluence conditions. The proliferative rate of PLF was higher than that of GF at 1, 4, and 7 days (p < 0.05). At 15 and 21 days, there was no statistically significant difference as to the number of cells. PLF presented a significantly greater proliferative potential, in relation to GF (p < 0.05). The synthesis of protein in a period of 24 hours was similar for both PLF and GF. Our results demonstrated that PLF and GF are different as to morphology and proliferative capacity, however, they do not differ as to protein synthesis.

Basaloid squamous carcinoma of oral cavity: a histologic and immunohistochemical study

Basaloid squamous carcinoma (BSC) is an aggressive variant of squamous cell carcinoma (SCC) with a predilection for the upper aerodigestive tract. In the English literature, approximately 40 cases of BSC have been described in the oral cavity. BSC has frequently been confused with adenoid cystic carcinoma (ACC), basal cell adenocarcinoma, and undifferentiated SCC. The purpose of the investigation was to examine the histological features and immunohistochemical expression of differentiation-related substances, including cytokeratin (CK) subtypes, vimentin, S-100, chromogranin, laminin, and type IV collagen, for the characterization of biological features of these tumours. We studied three cases of BSC of the oral cavity, three cases of ACC, and one case of basal cell adenocarcinoma. Well-differentiated and undifferentiated SCCs were also studied for comparison. The BSCs showed many histopathologic similarities to cases previously reported. Among the CK subtypes analyzed, CK14 was the only subtype expressed by all basaloid cells of BSC. Potentially useful for the differential diagnosis was the finding of CKs 7 and 19 expression in the basaloid cells of ACC, and CKs 7 and 8 in basal cell adenocarcinoma. In BSCs, laminin and type IV collagen were found in the microcystic spaces between basaloid cells, but neither ACCs nor basal cell adenocarcinoma showed this feature. These data suggest that immunohistochemical findings are helpful in distinguishing BSC of the oral cavity from other histopathologically similar tumours.

Transforming growth factor-beta1 autocrine stimulation regulates fibroblast proliferation in hereditary gingival fibromatosis

BACKGROUND

Hereditary gingival fibromatosis (HGF) is a rare oral disease characterized by a slow and progressive enlargement of both the maxilla and mandible gingiva. Increased proliferation, elevated synthesis of extracellular matrix, particularly collagen, and reduced levels of matrix metalloproteinases seem to contribute to the pathogenesis of gingival overgrowth in HGF patients. Transforming growth factor-beta1 (TGF-beta1) is an important cytokine thought to play a major role in fibrotic disorders such as HGF due to its ability to stimulate the synthesis and reduce the degradation of extracellular matrix. In HGF fibroblasts, TGF-beta1 autocrine stimulation reduces expression and production of matrix metalloproteinases. However, the role of TGF-beta1 in fibroblast growth modulation has not been established in this disease.

METHODS

The aim of this study was to confirm the increased proliferation rate of HGF fibroblast cell lines and to explore a possible autocrine role of TGF-beta1 as a cell growth stimulator by blocking production of this endogenous cytokine using 2 well-established systems: antisense oligonucleotides and neutralizing antibodies.

RESULTS

Four different cellular proliferation assays, bromodeoxyuridine labeling, argyrophilic nucleolar organizing region staining, proliferating cell nuclear antigen, and mitotic indexes, confirmed that fibroblasts from HGF proliferate significantly faster than those from normal gingiva. Antisense oligonucleotides reduced TGF-beta1 production as demonstrated by capture enzyme-linked immunosorbent assay, whereas TGF-beta1 expression levels were not significantly modified. Blocking TGF-beta1 synthesis with oligonucleotides or its activity with specific antibodies resulted in a decreased magnitude of HGF fibroblast proliferation.

CONCLUSION

These results are consistent with the existence of an autocrine role of TGF-beta1 as a stimulator of HGF fibroblast proliferation.

Morphometric evaluation of gingival overgrowth and regression caused by cyclosporin in rats

Cyclosporin A is a selective immunosuppressant, used in organ transplants to prevent graft rejection. Cyclosporin A can cause various side effects including gingival overgrowth. The aim of this work was to evaluate gingival overgrowth of rats treated daily with 10 mg/kg bodyweight of cyclosporin A for 60 days, as well as the regression after the interruption of treatment. All rats treated with cyclosporin A developed gingival overgrowth, with increased thickness of the epithelium, height and width of the connective tissue. The density of fibroblasts and collagen fibers also increased. Five to 90 days after the interruption of treatment with cyclosporin A, there was a progressive reduction of the gingival volume and of collagen fibers and fibroblast densities. The reduction was more pronounced in the initial periods and after 90 days did not return to the normal values.