Propolis: A useful agent on psychiatric and neurological disorders? A focus on CAPE and pinocembrin components.

Propolis consists of a honeybee product, with a complex mix of substances that have been widely used in traditional medicine. Among several compounds present in propolis, caffeic acid phenethyl ester (CAPE), and pinocembrin emerge as two principal bioactive compounds, with benefits in a variety of body systems. In addition to its well-explored pharmacological properties, neuropharmacological activities have been poorly discussed. In an unprecedented way, the present review addresses the current finding on the promising therapeutic purposes of propolis, focusing on CAPE and pinocembrin, highlighting its use on neurological disturbance, as cerebral ischemia, neuroinflammation, convulsion, and cognitive impairment, as well as psychiatric disorders, such as anxiety and depression. In addition, we provide a critical analysis, discussion, and systematization of the molecular mechanisms which underlie these central nervous system effects. We hypothesize that the pleiotropic action of CAPE and pinocembrin, per se or associated with other substances present in propolis may result in the therapeutic activities reported. Inhibition of the pro-inflammatory cascade, antioxidant activity, and positive neurotrophic modulatory effects consist of the main molecular targets attributed to CAPE and pinocembrin in health benefits.

Matrix stiffness mechanically conditions EMT and migratory behavior of oral squamous cell carcinoma.

Tumors are composed of heterogeneous phenotypes, each having different sensitivities to the microenvironment. One microenvironment characteristic - matrix stiffness - helps to regulate malignant transformation and invasion in mammary tumors, but its influence on oral squamous cell carcinoma (OSCC) is unclear. We observed that, on stiff matrices, a highly invasive OSCC cell line (SCC25) comprising a low E-cad to N-cad ratio (InvH/E:NL; SCC25) had increased migration velocity and decreased adhesion strength compared to a less invasive OSCC cell line (Cal27) with high E-cad to N-cad ratio (InvL/E:NH; Cal27). However, InvL/E:NH cells acquire a mesenchymal signature and begin to migrate faster when exposed to prolonged time on a stiff niche, suggesting that cells can be mechanically conditioned. Owing to increased focal adhesion assembly, InvL/E:NH cells migrated faster, which could be reduced when increasing integrin affinity with high divalent cation concentrations. Mirroring these data in human patients, we observed that collagen organization, an indicator of matrix stiffness, was increased with advanced disease and correlated with early recurrence. Consistent with epithelial tumors, our data suggest that OSCC cells are mechanically sensitive and that their contribution to tumor progression is mediated in part by this sensitivity.This article has an associated First Person interview with the first author of the paper.

Continuing education activities improve dentists' self-efficacy to manage oral mucosal lesions and oral cancer.

OBJECTIVES: This cross-sectional study aims to evaluate whether Continuing Education Activities (CEA) influence dentists' behaviour in relation to oral lesions. The secondary aim is to assess the association between dentists' perception of learning adequacy and self-efficacy for oral mucosal lesion management. METHODS: A self-administered online questionnaire was conducted on dentists working at the public health system of Rio Grande do Sul State, Brazil. The questionnaire included questions pertaining to perception of adequacy for oral diagnosis classes upon graduation, participation in oral cancer CEA and self-efficacy in managing oral mucosal lesions. RESULTS: 221 dentists from 91 municipalities answered the questionnaire. Most participants were female (71.5%) with a mean age of 38.3 years. Perception of learning as adequate during undergraduate coursework was associated with self-efficacy to diagnose, biopsy, and treat oral mucosal lesions (P < .05, Chi-squared test). However, 83.3% of dentists considered the time devoted to these topics prior to graduation insufficient. The frequency of oral lesion detection was related to self-efficacy to treat oral lesions and detecting oral cancer (P < .05, Chi-squared test). Among dentists who detected oral lesions frequently, 88.9% had attended CEA, whereas 11.1% of them had never attended these activities. CONCLUSIONS: CEA may improve awareness and efficacy of primary healthcare professional's detection of oral cancer.

Prognostic value of CRTC1-MAML2 translocation in salivary mucoepidermoid carcinoma: Systematic review and meta-analysis.

The presence of the CRTC1-MAML2 translocation has been described in mucoepidermoid carcinoma (MEC) as a predictor of better survival rates. However, the real prognostic value of the translocation has been debated due to recent controversial findings. The aim of this study was to perform a systematic review to understand the prognostic potential of the CRTC1-MAML2 translocation in MEC. An electronic search was carried out using the MEDLINE/PubMed, EMBASE and Scopus databases. Articles that assessed the association between the CRTC1-MAML2 translocation and survival of MEC patients were selected for the systematic review. Ten published articles were included in the qualitative synthesis. The prevalence of the translocation varied from 33.7% to 69.7%. Seven studies observed a significant association between the presence of the CRTC1-MAML2 translocation and a favourable clinical outcome, which could improve disease-free, disease-specific or overall survival. Five studies were included in the quantitative synthesis. Fixed-effects model confirmed that translocation-positive patients have a decreased risk of death (combined odds ratio 0.08, 95% confidence interval - 0.03-0.23, P < .00001). The detection of the CRTC1-MAML2 translocation appears to be useful as a prognostic factor in MEC. However, the level of evidence is not as high as it could be once important limitations were found in the published studies.

Photobiomodulation therapy improves human dental pulp stem cell viability and migration in vitro associated to upregulation of histone acetylation.

This in vitro study evaluated the role of photobiomodulation therapy (PBMT) on viability and migration of human dental pulp stem cells (hDPSCs) and its association to epigenetic mechanisms such as histone acetylation. The hDPSCs were characterized and assigned into control and PBMT groups. For the PBMT, five laser irradiations at 6-h intervals were performed using a continuous-wave InGaAlP diode laser. Viability (MTT), migration (scratch), and histone acetylation H3 (H3K9ac immunofluorescence) were evaluated immediately after the last irradiation. PBMT significantly increased the viability (P = 0.004). Also, PBMT group showed significantly increased migration of cells in the wound compared to the control in 6 h (P = 0.002), 12 h (P = 0.014) and 18 h (P = 0.083) being faster than the control, which only finished the process at 24 h. PBMT induced epigenetic modifications in hDPSC due to increased histone acetylation (P = 0.001). PBMT increased viability and migration of hDPSCs, which are related with the upregulation of histone acetylation and could be considered a promising adjuvant therapy for regenerative endodontic treatment.

A multicentre study of 268 cases of calcifying odontogenic cysts and a literature review.

OBJECTIVES: To investigate the frequency of calcifying odontogenic cysts (COCs) that have been submitted for microscopic examination from representative geographic regions of Brazil and to compare it with literature data. MATERIALS AND METHODS: A retrospective study was conducted on biopsies obtained from 1953 to 2016 at 10 Brazilian oral and maxillofacial pathology centres. A total of 198,350 biopsy specimens were analysed. Demographic data and histopathological diagnosis were evaluated descriptively and statistically. In addition, a literature review of case series was carried out in four electronic databases. RESULTS: A total of 268 cases of COC were surveyed, representing 0.1% of the oral lesions at the centres studied. Female patients in their second decade of life and the maxilla were more affected. The mean lesion size of symptomatic individuals was larger than that of cases without symptoms (p = 0.026). The literature review showed a higher frequency in Asia and Europe, mainly affecting men in the third decade of life. CONCLUSIONS: COC is a rare lesion. Novel data on the clinicopathological features of 268 cases have been added to the literature. Data regarding gender and age of the Brazilian patients reported herein contrast with findings of case series and retrospective studies reported elsewhere.

Hypoacetylation of acetyl-histone H3 (H3K9ac) as marker of poor prognosis in oral cancer.

AIMS: Epigenetics refers to changes in cell characteristics that occur independently of modifications to the DNA sequence. Oral carcinogenesis is influenced by modifications in epigenetic mechanisms, including changes in histones, which are proteins that support chromatin remodelling for the dynamic regulation of gene expression and silencing. The dysregulation of histone acetylation can lead to the uncontrolled activity of different genes, thereby triggering events associated with malignant transformation. The aim of this study was to analyse the expression of acetyl-histone H3 at lys9 (H3K9ac) in oral leucoplakia (OL) and oral squamous cell carcinoma (OSCC) in addition to its association with cell proliferation, epithelial-mesenchymal transition (EMT) and clinical-pathological findings. METHODS AND RESULTS: Samples of normal oral mucosa (NOM), OL and OSCC were submitted to immunohistochemical analysis using anti-H3K9ac, Ki67 and vimentin. Slides were submitted to quantitative analysis regarding the percentage of positive cells. OSCC presented less expression of H3K9ac in comparison to OL (P < 0.01), whereas Ki67 and vimentin levels increased from OL to OSCC (P < 0.001 and P = 0.03, respectively). OSCC patients with poor prognosis had less H3K9ac expression (P = 0.04). The Kaplan-Meier cumulative survival curves also revealed lower survival rates in patients with less H3K9ac expression (P < 0.01). CONCLUSIONS: The present findings suggest that changes in H3K9ac occur during the process of oral carcinogenesis along with an increase in cell proliferation and EMT. The results demonstrate that H3K9ac may be a useful novel prognostic marker for OSCC.

New photobiomodulation protocol prevents oral mucositis in hematopoietic stem cell transplantation recipients-a retrospective study.

Oral mucositis (OM) is an adverse side effect among hematopoietic stem cell transplantation (HSCT) recipients. The objective of this retrospective study was to evaluate the preventive effect of photobiomodulation (PBM) applied three times per week versus seven times per week in patients undergoing HSCT. The risk factors related to the incidence and severity of OM were also assessed. This was a retrospective study that evaluated 99 HSCT recipients who received different PBM protocols. Group I received three sessions per week, and group II received daily treatment. PBM was applied using a continuous-wave diode laser (InGaAlP; MM Optics, São Carlos, SP, Brazil) at a wavelength of 660 nm (visible-red) and a total radiant energy of 0.24 J per point. The baseline disease, type of transplant, type of conditioning, prophylaxis against graft-versus-host disease, OM grade, absolute leukocyte and platelet counts, and levels of liver and renal function markers were collected from medical records. The patients' age ranged from 13 to 71 years (mean/SD, 40.54 ± 16.45). No significant difference was observed between groups I and II regarding sex, age, ethnic, diagnosis, donor type, and conditioning treatment. Both PBM protocols were equally efficient in preventing OM (p = 0.34, ANOVA). Independent of the PBM protocol used, patients who received allogeneic transplant (p < 0.01-Fischer's exact test), total body irradiation (TBI-12Gy) (p = 0.01-chi-square test), busulfan + cyclophosphamide (p < 0.01-chi-square test), or methotrexate-containing regimens (p < 0.01-Fischer's exact test) demonstrated higher OM incidence and severity. Myelosuppression (p < 0.01-Mann-Whitney test) and impaired renal function (p = 0.02-Mann-Whitney test) were also considered risk factors for OM. Based on this retrospective data, PBM was effective in preventing OM in patients undergoing HSCT even when it was applied three times a week. A prospective study might be necessary to confirm these findings.

Teledentistry: A Tool to Promote Continuing Education Actions on Oral Medicine for Primary Healthcare Professionals.

BACKGROUND: Difficulties in diagnosis of oral mucosal lesions are a significant cause of delayed oral cancer diagnosis, and this difficulty may be due to gaps in knowledge. This study evaluated the diagnostic skills of primary healthcare professionals regarding oral cancer and presented them with an e-learning course. MATERIALS AND METHODS: Forty-seven primary healthcare professionals (32 dentists and 15 nondentists) enrolled in a 24-h course on oral medicine delivered through an e-learning platform. A test, based on 33 clinical images of oral lesions, was used to evaluate the diagnostic skills of participants. The participants were requested to classify each lesion as benign, potentially malignant, or malignant as well as to inform their clinical impression. Three specialists also took the test as the gold standard. RESULTS: Twenty-seven participants completed the test. Nondentists and dentists showed a comparable sensitivity of 68.8 ± 11.1 and 63.7 ± 15.8, respectively. Specialists performed somewhat better; however, the difference was not statistically significant (81.0% ± 4.1%, p = 0.16). Dentists and specialists (70.0% ± 16.6% and 95.5% ± 3.1%, respectively) showed higher specificity than nondentists (39.3 ± 20.6, p < 0.01). Nondentists had a higher number of unanswered questions (p < 0.01) for classification and clinical impression (50.0% ±45.1% and 72.0% ± 25.0%, respectively) than dentists (5.7% ±11.9% and 19.8% ± 20%, respectively). Both dentists and nondentists had low attendance in the course (44.57% ± 37.38% and 26.53% ± 26.53%, respectively, p = 0.26). To the best of our knowledge, this is the first study to assess the diagnostic skills of public health workers belonging to different professional categories. CONCLUSION: Both dentists and nondentists have a fairly good capacity for discriminating the nature of oral lesions. Early squamous cell carcinoma is the most challenging situation and remains an issue to be addressed.

Semaphorins and neuropilins expression in salivary gland tumors.

BACKGROUND: Salivary gland tumors (SGT) account for 3-10% of all head and neck neoplasms, and little is known about their angiogenic properties. Despite semaphorins and neuropilins have been demonstrated to be prognostic determinants in many human cancers, they remain to be investigated in SGT. Therefore, the objective of this study was to analyze the clinical significance of the expression of class 3 semaphorins A (Sema3A) and B (Sema3B) and neuropilins-1 (Np-1) and neuropilins-2 (Np-2), in SGT. METHODS: Two hundred and forty-eight SGT were organized in tissue microarray paraffin blocks and expression of CD34, Sema3A, Sema3B, Np-1, and Np-2 was determined through immunohistochemistry. The immunoreactions were quantified using digital algorithms and the results correlated with clinicopathological parameters. RESULTS: Malignant tumors had an increased vascular density than their benign counterparts and their increased vascular area significantly correlated with recurrences (P < 0.05). Patients older than 40 years and the presence of recurrences determined an inferior survival rate (P = 0.0057 and P = 0.0303, respectively). In normal salivary glands, Np-1 and Np-2 expression was restricted to ductal cells, whereas Sema3A and Sema3B were positive in the serous acinar compartment. Tumors were positive for all markers and the co-expression of Np-1/Np-2 significantly correlated with the presence of paresthesia and advanced stages of the tumors (P = 0.01 and P = 0.04, respectively). CONCLUSION: Sema3A, Sema3B, Np-1, and Np-2 may be involved in the pathogenesis of SGT, but their expression did not present a statistically significant prognostic potential in this study.

Gingival Cysts of Adults: Retrospective Analysis from Two Centers in South Brazil and a Review of the Literature.

Gingival cysts of adults are rare developmental cysts, with an incidence of 0.3% among all odontogenic cysts. They are benign, well-defined nodules located on the attached gingiva with a fluid-filled appearance. The aim of the present study was to perform an analysis of gingival cysts in adults diagnosed at an oral pathology laboratory and a hospital pathology service in order to determine the frequency of occurrence of this lesion, and to perform a literature review to correlate the present findings with those described in the literature. This study emphasizes the low frequency of gingival cysts in adults and the importance of gathering clinical, radiographic and histopathological information to define the final diagnosis.

Social networking website increases efficacy and engagement in a distance learning course about oral lesions.

PURPOSE: Distance learning appears to be an attractive approach to continuing education courses, but one barrier is maintaining learner engagement throughout the course. The primary aim of this research was to evaluate the operational efficacy of a private Facebook™ group (FG) in serving as a support mechanism for distance learning courses, and its impact on three fundamental dimensions: the attrition rates of participants who did not complete the course (commonly referred to as dropout rates), the rates of course completion and approval, and the overall performance of the participants. METHODS: The participants of this quasi-experimental study comprised 159 dental students and 565 dentists enrolled in an e-learning course on oral mucosal lesion diagnosis. Prior to the initiation of the course, all participants were provided with the option to join a private FG. Within this group, moderators shared motivational messages and provided reminders concerning deadlines. Moreover, participants had the opportunity to engage in interactive discussions pertaining to topics related to the course. The course itself followed a self-guided format, employing the flipped-classroom methodology, spanning a total of 50 instructional hours. In order to assess the effectiveness of the course, participants were presented with photographs illustrating 30 oral lesions and were asked to propose diagnostic hypotheses both before and after the educational intervention (pre-tests and post-tests). RESULTS: Dentists who participated in the FG exhibited a significantly lower rate of discontinuation. As for dental students, their involvement in the group was positively associated with better performance, as determined by the percentage of accurate diagnostic hypotheses (a minimum of 70% correct responses was required for their approval in the course). CONCLUSIONS: Facebook™ demonstrates promise as a supplementary pedagogical tool in distance education courses. The interactive nature of the platform has the potential to alleviate the inherent challenges of remote learning.

Cell contractility drives mechanical memory of oral squamous cell carcinoma.

Matrix stiffening is ubiquitous in solid tumors and can direct epithelial-mesenchymal transition (EMT) and cancer cell migration. Stiffened niche can even cause poorly invasive oral squamous cell carcinoma (OSCC) cell lines to acquire a less adherent, more migratory phenotype, but mechanisms and durability of this acquired "mechanical memory" are unclear. Here, we observed that contractility and its downstream signals could underlie memory acquisition; invasive SSC25 cells overexpress myosin II (vs. noninvasive Cal27 cells) consistent with OSCC. However, prolonged exposure of Cal27 cells to a stiff niche or contractile agonists up-regulated myosin and EMT markers and enabled them to migrate as fast as SCC25 cells, which persisted even when the niche softened and indicated "memory" of their prior niche. Stiffness-mediated mesenchymal phenotype acquisition required AKT signaling and was also observed in patient samples, whereas phenotype recall on soft substrates required focal adhesion kinase (FAK) activity. Phenotype durability was further observed in transcriptomic differences between preconditioned Cal27 cells cultured without or with FAK or AKT antagonists, and such transcriptional differences corresponded to discrepant patient outcomes. These data suggest that mechanical memory, mediated by contractility via distinct kinase signaling, may be necessary for OSCC to disseminate.

Oral desmoplastic melanoma mimicking inflammatory hyperplasia.

INTRODUCTION: Desmoplastic melanoma (DM) arising in the oral cavity is a rare neoplasm that may be confused with a variety of non-melanocytic benign or malignant lesions. OBJECTIVES: To present a case of DM in the oral mucosa mimicking fibrous inflammatory hyperplasia, discusses the difficulties involved in the diagnosis and offers a literature review on the clinicopathologic and immunohistochemincal aspects of this neoplasm. CASE REPORT: A 62-year-old white male, smoker, was referred with a chief complaint of pain and swelling in the palate. The oral examination revealed multiple brown-to-black patches and a non-pigmented sessile nodule located on the mucosa of the hard palate. The clinical diagnosis of the pigmented lesions was either oral melanosis or melanoma. The nodular lesion was clinically diagnosed as fibrous inflammatory hyperplasia. Incisional biopsy was performed on the pigmented lesion and the microscopic sections revealed a melanotic macule. The nodular lesions histologically revealed an amelanotic desmoplastic melanoma. CONCLUSIONS: Reactive lesions close to a pigmented area should be investigated with great care.

Leishmaniasis with oral mucosa involvement.

INTRODUCTION: The term leishmaniasis comprises a group of diseases caused by different protozoan species of the genus Leishmania. There are three main clinical forms of leishmaniasis: visceral, cutaneous and mucocutaneous. Exclusive involvement of the mucosa is very rare. OBJECTIVES: To present a case of mucocutaneous leishmaniasis in an elderly patient, discuss the clinical presentation, diagnostic process and treatment emphasizing the distinctions from other granulomatous lesions. CASE REPORT: A 71-year-old male presenting with a symptomatic lesion on the hard and soft palate, which had developed over a period of 6 months was evaluated. The oral exam revealed a lesion with multiple ulcerated nodules on the hard and soft palate extending to the oropharynx. The diagnostic hypothesis was chronic infectious disease (paracoccidioidomycose, tuberculosis and leishmaniasis) or squamous cell carcinoma. Histopathological, histochemical and immunohistochemical analysis were performed. A chest x-ray revealed a normal pulmonary pattern. The Montenegro skin test was positive. The definitive diagnosis was leishmaniasis with exclusive oral manifestation and the patient was treated with liposomal amphotericin. CONCLUSIONS: Localized oral mucosa leishmaniasis is an uncommon event in an immunocompetent patient. Dentists play an important role in the diagnosis of oral leishmaniasis, which has systemic repercussions.

Healing action of topical chamomile on 5-fluoracil induced oral mucositis in hamster.

BACKGROUND: Oral mucositis is a common complication in the treatment of cancer. Its management and prevention are seen as high priority in cancer patient care. The aim of the present study was to investigate the effect of topical chamomile in the treatment of oral mucositis induced by 5-fluoracil (5-FU) in hamsters. MATERIALS AND METHODS: One hundred five hamsters were randomly separated into three groups (35 animals each): group I--without treatment (control); group II--treatment with chamomile (Ad-Muc®); and group III--treatment with corticoid (betamethasone elixir--Celestone®). The animals received an intraperitoneal injection of 5-FU on days 0 and 2. On days 3 and 4, the buccal mucosa was scratched and therapy was initiated on day 5. Three animals were sacrificed on days 0, 2, 5, 8, 10, 12, 14, and 16, weighed, and the buccal mucosa removed for clinical and histopathological analysis. RESULTS: The animals that developed mucositis and were treated with chamomile or the corticoid agent weighed significantly less than those in the control group. The group treated with the corticoid agent exhibited a more severe clinical condition, whereas the group treated with chamomile exhibited mild mucositis throughout the experiment. The group treated with chamomile had a 12-fold greater chance of scoring zero (absence of mucositis) than the control group. Analysis of the histopathological results demonstrated that the group treated with chamomile exhibited a lesser degree of mucositis throughout the evaluation period in comparison to the control and corticoid groups. CONCLUSION: Chamomile proved effective in the treatment of oral mucositis in a hamster model. However, well-designed clinical studies are needed to confirm the clinical efficacy of this medicine in humans.

No effect of low-level lasers on in vitro myoblast culture.

Effects of phototherapy using low-level lasers depend on irradiation parameters and the type of laser used. The aim of the present study was to evaluate the effect of phototherapy on the proliferation of cultured C2C12 myoblasts under different nutritional conditions using low-level GaAlAs and InGaAlP lasers with different parameters and incubation periods. C2C12 cells cultured in regular and nutrient-deficient medium were irradiated with low-level GaAlAs (780 nm) and InGaA1P (660 nm) lasers with energy densities of 3.8, 6.3 and 10 J/cm2, and 3.8, 10 and 17.5 J/cm2, respectively. Cell proliferation was assessed 48 and 72 h after irradiation by MTT assay. There were no significant differences in cell proliferation between laser-treated myoblasts and control cultures for any of the parameters and incubation periods. Further studies are necessary to determine the correct laser parameters for optimizing the biostirhulation of myoblasts.

Photobiomodulation therapy drives massive epigenetic histone modifications, stem cells mobilization and accelerated epithelial healing.

Emerging evidence indicates the clinical benefits of photobiomodulation therapy (PBMT) in the management of skin and mucosal wounds. Here, we decided to explore the effects of different regiments of PBMT on epithelial cells and stem cells, and the potential implications over the epigenetic circuitry during healing. Scratch-wound migration, immunofluorescence (anti-acetyl-Histone H3, anti-acetyl-CBP/p300 and anti-BMI1), nuclear morphometry and western blotting (anti-Phospho-S6, anti-methyl-CpG binding domain protein 2 [MBD2]) were performed. Epithelial stem cells were identified by the aldehyde dehydrogenase enzymatic levels and sphere-forming assay. We observed that PBMT-induced accelerated epithelial migration and chromatin relaxation along with increased levels of histones acetylation, the transcription cofactors CBP/p300 and mammalian target of rapamycin. We further observed a reduction of the transcription repression-associated protein MBD2 and a reduced number of epithelial stem cells and spheres. In this study, we showed that PBMT could induce epigenetic modifications of epithelial cells and control stem cell fate, leading to an accelerated healing phenotype.

BDNF/TrkB/Akt Signaling Pathway Epithelial Odontogenic Tumors and Keratocyst: An Immunohistochemical Study Comparative With Dental Germs.

Odontogenic lesions (OL) are an important group of oral and maxillofacial diseases represented by odontogenic cysts, benign, and malignant tumors. The brain-derived neurotrophic factor (BDNF)/ tropomyosin receptor kinase B (TrkB) signaling pathway has multiple biological actions and has been identified as an important pathway in the proliferation, invasion, and survival of different epithelial tumors. Its role in the development of OL, however, has so far been unexplored. Our aim was to evaluate the BDNF/TrkB/Akt/p-RPS6 signaling pathway in OL of epithelial origin. This cross-sectional study comprised 3 cases of tooth germs, 25 cases of odontogenic keratocyst (OK), 29 cases of ameloblastoma (Am), and 6 cases of ameloblastic carcinoma. Immunohistochemical staining for BDNF, TrkB, p-Akt, and p-RPS6 was performed. OLs were evaluated according to the pattern of immunohistochemical expression in epithelial cells and by semiquantitative scores that considered the intensity of staining and percentage of positive cells. BDNF stromal expression was also assessed. No significant differences were observed with respect to the percentage of positive cases for all markers. Regarding the immunoreactive scores, BDNF and p-RPS6 expressions were similar in the odontogenic epithelium of all OL. However, TrkB and p-Akt were overexpressed in OK compared with ameloblastic carcinoma. In Am, epithelial BDNF was significantly higher compared with stromal expression. In conclusion, BDNF seems to participate in the development of cystic, benign, and malignant odontogenic epithelium to similar degrees. The acquisition of the invasive or malignant phenotype in odontogenic neoplasms is not associated with alterations in the BDNF/TrkB/Akt/RPS6 axis, which could be implicated in the differentiation process.