Synchronous cemento-ossifying fibromas: a systematic review.

BACKGROUND: This systematic review aimed to incorporate published data regarding synchronous cemento-ossifying fibromas (COF), with an analysis of their demographic and clinicopathological characteristics. MATERIAL AND METHODS: Case reports and case series of synchronous COF were searched in PubMed, Web of Science, Scopus, EMBASE, and LILACS according to the PRISMA (2020) statement. Also, a manual search was carried out and the grey literature was assessed. A descriptive statistical analysis was performed. RESULTS: Nineteen studies comprising 20 cases of synchronous COF were included. The mean age at diagnosis was 35 years (±13.8), with a predominance of female patients (n=12/60%). In 13 cases (65%) the mandible and the maxilla were affected simultaneously. In two cases (10%) first-degree relatives (parents or siblings) had been previously diagnosed with COF. The diagnostic hypotheses were reported in 8 cases (40%), with florid cemento-osseous dysplasia, ameloblastic fibroodontoma, calcifying cystic odontogenic tumor, osteoma and cementoblastoma being cited in the differential diagnosis. Among the cases with details about management (n=17), eleven were treated by surgical enucleation and/or excision (64.7%). Follow-up was provided for 10 cases (50%), with a mean period of 44.7±62.19 months. Recurrence occurred in three of informed cases. CONCLUSIONS: Synchronous manifestation of COF is rare. Female patients around the 3rd decade of life are more commonly affected. Bilateral involvement of the mandible and maxilla is the most common clinical presentation.

Oral pathology and oral medicine in Latin American countries: current stage.

BACKGROUND: Oral Pathology (OP) and Oral Medicine (OM) are specialties in dentistry whose main objective is the diagnosis and treatment of oral and maxillofacial diseases, and aspects related to the academic training of professionals and fields of practice are distinct and heterogeneous around the world. This study aimed to evaluate professional training and areas of activity in OP and OM in Latin American countries. MATERIAL AND METHODS: A questionnaire was sent to 11 countries, with a professional in each country responsible for answering it. The questionnaire had 21 questions related to the process of professional training, areas of practice, the existence of scientific events in each country, and also collected demographic and population information. RESULTS: OP and OM are practiced in all the countries studied, but the specialty is not recognized in all of them. Brazil was the first to recognize both as a specialty. Postgraduate programs designed to train specialists are available in various countries. Two countries offer residency programs, 6 countries provide specialization courses, 6 offer master's programs, and 3 have doctoral programs. Brazil boasts the highest number of undergraduate courses (n=412), while Uruguay has the lowest (n=2). Professional societies representing the specialty exist in ten countries. Brazil has the highest number of OP and OM specialists (n=422 and 1,072), while Paraguay has the smallest number (n=1 and 3). CONCLUSIONS: Although both specialties are widely practiced around the globe, professional training, the number of dentists trained and the fields of professional practice are very different between the countries studied.

Frequency of BRAF V600E immunoexpression in ameloblastomas: a multi-institutional analysis of 86 cases in Latin America and comprehensive review of the literature.

BACKGROUND: Paracoccidioidomycosis (PCM) is the leading cause of death among systemic mycoses in Brazil. On the other hand, oral squamous cell carcinoma (OSCC) is the most prevalent malignant neoplasm of the mouth. Both lesions rarely affect the tongue dorsum and may share similar clinical characteristics. This study aimed to retrieve cases of single oral ulcers diagnosed as PCM or OSCC. MATERIAL AND METHODS: A cross-sectional retrospective study was conducted. All patients who had a single ulcer on dorsum of the tongue and confirmed diagnosis of PCM or OSCC were evaluated. RESULTS: A total of 9 patients (5 women and 4 men) were evaluated, 5 patients had OSCCs (mean age = 69,8 years old), and 4 patients PCM (mean age = 51 years old). Most of the lesions were infiltrated and indurated in the palpation exam. Duration ranged from 1 to 12 months (mean time of 5.2 months and 4.7 months for OSCC and PCM, respectively). OSCC was the main clinical diagnosis hypothesis. CONCLUSIONS: Although uncommon, PCM and OSCC should be considered as a differential diagnosis hypothesis in infiltrated ulcers on the tongue dorsum. Incisional biopsy is mandatory to confirm the diagnosis and indicate the appropriate treatment.

DNA oxidative damage in oral cancer: 8-hydroxy-2´-deoxyguanosine immunoexpression assessment.

BACKGROUND: The development and establishment of oral squamous cell carcinoma are confined to carcinogenesis, which involves oxidative stress via oxygen-free radical production as a hydroxyl radical (HO•), considered the most important cause of oxidative damage to basic biomolecules since it targets DNA strands. 8-Hydroxy-2´-deoxyguanosine (8-OHdG) is considered a free radical with a promutagenic capacity due to its ability to pair with adenosine instead of cytosine during replication. MATERIAL AND METHODS: We collected 30 paraffin-embedded tissue samples of OSCC from patients treated between 2013 and 2018. We recorded risk habits, disease stage, disease free survival and death with at least 3 years of follow-up. 8-Hydroxyguanosine was evaluated by immunohistochemistry and subsequently classified as weak-moderate or strong positive expression. Additionally, we noted whether it was expressed in the cytoplasm and/or nucleus. RESULTS: Most of the cases expressed 8-OHdG with a strong intensity (80%). All neoplastic cells were preferentially stained in only the cytoplasm (70.0%), but nuclear positivity was found in 30%, independent of the intensity. Based on the location in the cytoplasm and/or nucleus, tumors >4 cm showed a high frequency (95.5%) of 8-OHdG expression in only the cytoplasm, with a significant difference (p value 0.001). Additionally, overall survival was affected when immunoexpression was present in the cytoplasm and nucleus because all deaths were in this group were statistically significant (p value = 0.001). CONCLUSIONS: All tumors showed DNA oxidative damage, and 8-OHdG was preferentially expressed in the cytoplasm. This finding was associated with tumor size and, when present in the nucleus, might also be related to death.

Stafne's bone defect: a systematic review.

BACKGROUND: This systematic review integrated the available data published in the literature on Stafne's bone defect (SBD), considering the clinical, imaging and histopathological results. MATERIAL AND METHODS: An electronic search was undertaken in six databases. Eligibility criteria were: articles in English, Spanish, and Portuguese describing case reports or case series of SBD, reported up to September/2021. Risk of bias was assessed using the Joanna Briggs Institute tool. RESULTS: A total of 98 articles were retrieved, involving 465 individuals with SBD and were included for quantitative analysis. Mean age was 52.78 years (range: 11-89 years), with male predilection (n=374/80.85%). Radiographs were the most frequent imagiological exams (n=298/64.09%), followed by computed tomography (n=98/21.08%). SBD was more prevalent in the posterior mandible (n=361/93.77%) as a hypodense radiolucent lesion (n=250/77.40%). Mean size was 1.58 cm (range: 0.3-.8.0 cm). Two-hundred-and-two lesions (97.37%) were unilocular and 126 (91.97%) were classified as well-defined. Clinical symptoms were reported in 73 cases, while 68 cases (93.15%) were asymptomatic. Only 34 cases (12.32%) were submitted to histopathological examination. Mean follow-up time was 26.42 ±25.39 months. CONCLUSIONS: SBD is more frequent in male patients in the fifth and sixth decade of life. Classic SBD is radiographically characterized as a single, unilocular and well-defined lesion in the posterior region of the jaw with a radiolucent/hypodense appearance.

The value of Phosphohistone H3 as a cell proliferation marker in oral squamous cell carcinoma. A comparative study with Ki-67 and the mitotic activity index.

BACKGROUND: The Phosphohistone H3 (PHH3) antibody is recognized as a biomarker of cell proliferation, specific for cells in mitosis, of prognostic value in different malignant neoplasms, however it has been poorly studied in oral squamous cell carcinoma (OSCC). The main objective of this study was to evaluate the immunoexpression of the PHH3 in the OSCC, through the correlation with the immunoexpression of Ki-67, the mitotic activity index (MAI), histological grading, clinical-morphological parameters and the rate of survival. MATERIAL AND METHODS: The study sample consisted of 62 cases of OSCC diagnosed in the Pathological Anatomy Laboratory of the Faculty of Dentistry, University of the Republic (Uruguay). In each of them, an immunohistochemical technique was performed for Ki-67 and PHH3 (serine 10) antibodies. Image J software was used for the MAI and biomarker quantification, defining the percentage of positivity and mitotic figures per 1000 tumor cells. RESULTS: a significant association was obtained between the expression of PHH3 (p 0.016) and MAI (p 0.031) with survival time. However, no similar relationship was found with Ki-67 (p 0.295). Although it was confirmed a statistical association between histological grade and Ki-67 immunoexpression (p 0.004), PHH3 did not show a similar relationship (p 0.564). CONCLUSIONS: It was confirmed the role of the PHH3 antibody as a biomarker of mitotic figures in OSCC and as a potential marker of cell proliferation. It is noteworthy that this is one of the first works that evaluates a possible relationship between the expression of this antibody and survival in OSCC.

Ep-CAM (MOC-31) expression in tooth germ and ameloblastoma.

BACKGROUND: Ep-CAM, a transmembrane glycoprotein expressed in most epithelium in normal conditions, has diverse roles in these tissues, including in cell adhesion, proliferation, differentiation, cell cycle regulation, migration and intracellular signaling. It is also over-expressed in most malignant neoplasia, participating in the initiation, progression, and metastatic dissemination of the tumor. The expression and roles of this protein in oral neoplasia, particularly in odontogenic tumors, remain unestablished. The objective of this study consisted in analyzing the expression of this protein in ameloblastoma and tooth germ. MATERIAL AND METHODS: Ep-CAM (MOC-31) expression was evaluated by immunohistochemistry in tooth germs (TG) (n = 16) ameloblastomas (AM) (n = 60) and 2 ameloblastic carcinomas. Sections were visualized in their totality with an optical microscope, and positivity observed in cell membrane and cytoplasm was graded according to the following semi-quantitative scale: Neg, "essentially unstained", for negative sections or staining <5% of cells; + for staining of 5-50% of cells; ++ for staining >50% of cells. RESULTS: Most tooth germs expressed MOC-31 (81.3%), strong staining was observed both in the inner epithelium of the enamel organ and in the adjacent stellate reticulum. 16.7% of the AM cases showed MOC-31 expression, the immunoexpression expression was diffuse at the cytoplasmic and membrane level. The only two cases of ameloblastic carcinoma included were strong positive to MOC-31. No correlation was observed between protein expression and gender, age, clinical variants, or histological subtypes. CONCLUSIONS: Overexpression was found in TG and ameloblastic carcinoma compared to AM; further studies with different experimental strategies are suggested to clarify the biological significance of this finding.

Connexin 43, Bcl-2, Bax, Ki67, and E-cadherin patterns in oral squamous cell carcinoma and its relationship with GJA1 rs12197797 C/G.

BACKGROUND: To our knowledge, there is no useful and accurate prognostic biomarker or biomarkers for patients with oral squamous cell carcinoma (OSCC), a tumor with uncertain biological behavior, and unpredictable clinical progress. The purposes of this study were: a) to determine the expresión profile of Connexin 43, Bcl-2, Bax, E-cadherin, and Ki67 in patients with OSCC; b) identify the GJCA1 rs12197797 genotypic composition. MATERIAL AND METHODS: A cross-sectional study using genomic DNA and biopsy samples extracted from the oral mucosa with/without OSCC, older than 18 years, both genders, attended at Facultad de Odontología, Universidad Nacional Córdoba. Immunostaining for Cx43, Bcl-2, Bax, E-cadherin, and Ki67 and genotyping GJA1 rs12197797 by RFLP were performed. Odds Ratio (95% CI), Spearman Coefficient were estimated. Mann-Whitney test was applied to analyze immunostaining between controls/cases (p <0.05 was set for statistical significance). RESULTS: GG (mutant) was the most frequent genotype in patients with OSCC diagnosis (53.2%) in relation to CC "healthy" genotype (p=0.00487; OR=7.33; CI95% [1.1-54.7]). And, the allele G (mutant) had a presence in 75.5% of OSCC patients. However, no significant association was observed between alleles C/G and diagnosis (p=0.0565). The heterozygous genotype was the most frequent in the patients of both groups Cx43 and E-cadherin markers were lower in OSCCs in relation to controls. Ki67 and Bcl-2 immunolabeling were high on OSCC, and Bax immunomarker was diminished in OSCC. CONCLUSIONS: We hypothesized that the oral epithelium losses Connexin 43 and E-cadherin in the membrane, which modifies cell differentiation. The Ki67 and Bcl2 overexpression would increase the cell density in the tissue, by promoting proliferation and decreasing apoptosis. And, this study shows evidence that patients who carry on allele G of GJA1rs12197797 could be at risk of developing OSCC.

Localization of interleukin-6 signaling complex in epithelialized apical lesions of endodontic origin.

OBJECTIVES: We aimed to determine the immunolocalization patterns of the interleukin (IL)-6 signaling complex in epithelialized and non-epithelialized apical lesions of endodontic origin (ALEOs). MATERIALS AND METHODS: Epithelialized (n = 8) and non-epithelialized (n = 7) ALEOs were obtained from teeth with indication of extraction in patients with clinical diagnosis of apical periodontitis. All tissues were subjected to routine processing for histopathologic examination and primary antibodies for IL-6, IL-6 receptor (R), and glycoprotein (gp)-130 were used for immunohistochemistry and double immunofluorescence co-localization. RESULTS: IL-6, IL-6R, and gp-130 were immunolocalized in endothelial cells and mononuclear leukocytes in a diffuse pattern within the connective tissue of epithelialized and non-epithelialized ALEOs. In the epithelialized lesions, two different patterns were identified: IL-6 signaling complex was localized within the proliferating epithelium in a diffuse intracellular pattern and in a cell membrane localization pattern within the mature epithelial lining, showing a decreased intensity towards the surface layers. CONCLUSIONS: IL-6, IL-6R, and gp-130 localized to mononuclear inflammatory cells, vascular endothelial cells, and immature proliferating epithelia in a diffuse pattern and in mature lining epithelia in a localized cell membrane pattern, supporting a role for epithelial proliferation during cyst formation. Additional cell membrane co-localization of IL-6 receptor complex suggests classic signaling involvement in addition to trans-signaling.

Expression of caveolin-1 in tooth germ, ameloblastoma and ameloblastic carcinoma.

BACKGROUND: The caveolin-1 protein (structural component of membrane caveolae) plays important roles in several biological functions, such as endocytosis, cell adhesion, and cell signaling. However, this protein has been associated with mechanisms of tumorigenesis in several neoplasms. The expression patterns and roles of caveolin-1 in the oral epithelium and in embryonic and odontogenic tumor tissues are still unclear. MATERIAL AND METHODS: The expression of caveolin-1 was evaluated in samples of the normal gingival epithelium (n=7), human tooth germ (TG) (n=12), ameloblastoma (AM) (n=83), and ameloblastic carcinoma (AC) (n=9) by immunohistochemistry. Additionally, AM samples were analyzed by qRT-PCR and Western blot. RESULTS: Most TG (91.7%), AM (73.5%) and AC (100%) samples showed diverse patterns of immunohistochemical positivity for caveolin-1, while only one gingival sample was positive. The transcript levels of cav-1 were significantly upregulated by 14.9-fold in AM tissue (P = 0.0014) compared to those in normal gingival epithelial tissue, as shown by qRT-PCR. Presence of caveolin-1 protein was confirmed by Western blot analysis. The caveolin-1 immunoexpression patterns throughout the stages of TG show its importance during odontogenesis. CONCLUSIONS: The overexpression of caveolin-1 in AM and AC compared to its expression in normal gingival epithelium (adult tissue) suggests a possible role of caveolin-1 in protumoral events, but due to the similar immunoexpression observed in AM and AC, caveolin-1 may not necessarily participate in the malignant transformation process. However, future studies are needed to clarify and confirm these hypotheses.

Immunoexpression of galectin-3 and its potential relation to hypoxia-inducible factor-1α in ameloblastomas.

In tumor biology, hypoxia triggers signaling pathways that induce transcription of genes related to angiogenesis, metastasis, glucose metabolism and apoptosis. We investigated the expression of hypoxia related proteins, galectin-3 (Gal-3) and hypoxia-inducible factor-1α (HIF-1α), in conventional (CA) and unicystic ameloblastomas (UA). We applied immunohistochemistry for Gal-3 and HIF-1α to 72 cases of ameloblastoma: 59 cases of CA and 13 cases of unicystic UA. Immunoexpression was evaluated semiquantitatively. Gal-3 expression was observed in 40% of the cases: 23/59 CA and 6/13 UA. HIF-1α immunostaining was observed in 55% of cases: 36/59 CA and 4/13 UA. 19 CA and 2 UA were positive for both markers. Immunostaining was evident in the center of the tumor islands, which exhibited squamous metaplasia or cystic degeneration. The expression of Gal-3 and HIF-1α in ameloblastomas could be interpreted as a response to hypoxic stress. Co-expression of both proteins in CA may suggest a potential interaction that participates in the biological behavior of this ameloblastoma variant.

E-Cadherin gene expression in oral cancer: Clinical and prospective data.

BACKGROUND: Low protein expression of E-cadherin in oral squamous cell carcinoma (OSCC) has been associated with clinical and histopathological traits such as metastases, recurrence, low survival and poor tumor differentiation, and it is considered a high-risk marker of malignancy. However, it is still unknown whether low expression of E-cadherin is also present at the mRNA level in OSCC cases. OBJECTIVE: The aim of this study was to compare E-cadherin mRNA expression in OSCC patients and controls and to correlate the expression with clinical and prospective characteristics. MATERIAL AND METHODS: Forty patients and 40 controls were enrolled. E-cadherin mRNA expression was evaluated by quantitative real-time polymerase chain reaction using TaqMan probes. RESULTS: E-cadherin mRNA expression was significantly decreased in OSCC patients compared to that of controls (p<0.001). Whereas no significant association between clinical parameters and E-cadherin expression levels was observed, we noted lower E-cadherin expression levels in patients with positive lymph node metastasis. CONCLUSIONS: E-cadherin mRNA expression was markedly diminished in OSCC, in agreement with previous results that examined E-cadherin expression at the protein level. E-cadherin is downregulated in the early clinical stages of OSCC, and its mRNA levels do not change significantly in the advanced stages, suggesting that there is limited usefulness of this parameter for predicting disease progression.

Expression of proteoglycans in two types of ameloblastoma: novel Immunohistochemical findings.

Alterations in cellular and extracellular matrix components play an important role during tumorigenesis; proteoglycans are included among these components. Ameloblastomas are odontogenic tumors distinguished as invasive and infiltrative neoplasms and are divided into different histological types, the most common of which are the unicystic ameloblastoma and the conventional ameloblastoma. The aim of this study was to identify the presence of two proteoglycans, perlecan and biglycan, in different types of ameloblastoma. Using immunohistochemistry, we determined the presence of both proteins in 28 unicystic ameloblastomas and 23 conventional ameloblastomas. We identified the cytoplasmic and nuclear presence of perlecan and the cytoplasmic presence of biglycan in both types of ameloblastoma. The mean values of immunoexpression were higher in the conventional type compared to the unicystic type. Neither the presence of biglycan in ameloblastomas nor the nuclear presence of perlecan in any odontogenic tumor has previously been reported. The differential immunoexpression of perlecan and biglycan in these types of ameloblastomas suggests their participation in the developmental process of these tumors.

Primordial odontogenic tumor: Subepithelial expression of Syndecan-1 and Ki-67 suggests origin during early odontogenesis.

Primordial odontogenic tumor (POT) is composed of variably cellular myxoid connective tissue, surrounded by cuboidal to columnar odontogenic epithelium resembling the inner epithelium of the enamel organ, which often invaginates into the underlying connective tissue. The tumor is delimited at least partially by a thin fibrous capsule. It derives from the early stages of tooth development. Syndecan-1 is a heparan sulfate proteoglycan that has a physiological role in several cellular functions, including maintenance of the epithelial architecture, cell-to-cell adhesion and interaction of cells with extracellular matrix, and with diverse growth factors, stimulating cell proliferation. Ki-67 is considered the gold standard as a cell proliferation marker. The aim of this study was to examine the expression of Syndecan-1 and Ki-67 proliferation index in POT and normal tooth germs to better understand the biological behavior of this tumor. Results showed that Syndecan-1 was more intensely expressed in subepithelial mesenchymal areas of POT, in a pattern that resembles the early stages of tooth development. The cell proliferation index (4.1%) suggests that POT is a slow growing tumor. Syndecan-1 expression in tooth germs in late cap and early bell stages was similar to POT, showing immunopositivity in subepithelial mesenchymal condensed areas. The immunohistochemical findings showed a pattern in which the population of subepithelial mesenchymal cells exhibited greater proliferative activity than the central portion of the dental papilla.

Expresión de E-Cadherina y Syndecan-1 en Liquen Plano de Piel y de Mucosa Oral / Expression of E-Cadherin and Syndecan-1 in Oral and Skin Lichen Planus

El liquen plano es una lesión inmunológica que se caracteriza por presentar apoptosis de los queratinocitos basales, licuefacción de la membrana basal e infiltrado linfoplasmocitario en banda, estas características pudieran estar asociadas con la pérdida de adhesiones celulares y riesgo de transformación maligna. Para identificar el potencial regulatorio asociado a la adhesión celular de los queratinocitos basales y la posible capacidad de transformación maligna, se investigó la expresión "in situ" de E-cadherina y Syndecan-1 el liquen plano de piel y de mucosa oral. En un total de 37 casos de liquen plano de piel y 5 casos de liquen plano oral, se realizaron estudios de inmunohistoquímica para la detección de E-cadherina y Syndecan-1. En las áreas de enfermedad activa del liquen plano de piel los queratinocitos basales no expresaron E-cadherina y la expresión de Syndecan-1 fue focal, en las áreas de tejido epitelial libre de enfermedad la expresión de ambas proteínas fue muy similar. Los cambios de expresión de las proteínas E-cadherina y Syndecan-1 sugieren una posible asociación de las mismas a la patogénesis de Liquen plano de piel y de mucosa oral.

Lichen planus is an immunological lesion is characterized by basal keratinocytes apoptosis, liquefaction of the basal membrane and linphoplasmocitary infiltration, these features may be associated with loss of cellular adhesion and risk of malignant transformation. To identify the regulatory potential associated with cell adhesion of basal keratinocytes and the malignant transformation potential, the "in situ" expression of E-cadherin and Syndecan-1 proteins in skin and oral lichen planus were investigated. A total of 37 cases of skin lichen planus and 5 cases of oral lichen planus we reevaluated by immunohistochemical approach, using E-cadherin and Syndecan-1antibodies. In areas of active disease in skin lichen planus the basal keratinocytes did not express E-cadherin and Syndecan-1 expression was focal, in the of epithelial tissue areas of free lesion the expression of both proteins were similar. Changes in E-cadherin and Syndecan-1 expression suggest a possible association of this proteins with the pathogenesis of skin and oral lichen planus.

Prognostic factors and treatment strategies for adult head and neck soft tissue sarcoma.

Adult head and neck soft tissue sarcomas are rare and display a variety of histological types and clinical characteristics; they are also associated with a variety of mortality risks. The purpose of this study was to examine all patients treated at the Instituto Nacional de Cancerologia for head and neck sarcoma during a 5-year period. Fifty-one adult patients were examined and treated for head and neck sarcomas from 2004 to 2009. The 51 tumours were histologically re-evaluated by expert pathologists and classified as low, intermediate or high grade sarcomas. A multivariate analysis was performed to evaluate the surgical margins, histological grades, and clinical stages as prognostic factors for the disease. Adult head and neck soft tissue tumours are rare, and they are associated with poor prognosis for patients, especially at clinical stages III and IV. The average survival rate after 2 years is 45%, and most of these patients die because of disease progression and metastases.

Syndecan-1 (CD138) and Ki-67 expression in different subtypes of ameloblastomas.

Ameloblastoma is the most frequent odontogenic tumor and is considered a benign, but locally invasive, neoplasm with variable clinico-pathological expression. Syndecan-1 is a cell surface proteoglycan that binds cells to the extracellular matrix and its expression is down-regulated in many cellular transformation models. The aims of this study were to examine the pattern of syndecan-1 expression, to evaluate the proliferating activity in a large series of solid/multicystic (SA) and unicystic ameloblastomas (UA), and to study its possible correlation to their biological behavior. Immunohistochemical studies were performed for syndecan-1 (clone MI15) and Ki-67 (clone MIB-1) in 120 ameloblastomas (75 SA and 45 UA). The salient finding was that expression of syndecan-1 was related to the histological subtype of tumors, as there was a lower expression in SA (40.2%) as compared to UA (49.7%) (p<0.05). These findings did not correlate with Ki-67 expression, as this was similar in both types of ameloblastomas. Our results suggest that the reduced expression of syndecan-1 supports the view that SA has a more aggressive biological behavior than the UA. The lack of correlation between reduction of the syndecan-1 and Ki-67 index may be due to the different histomorphologies of both types of ameloblastoma, and more studies are necessary to better understand the role of this protein in the biological behavior of these tumors.