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Zhonghua Kou Qiang Yi Xue Za Zhi =... Aug 2023Ameloblastoma (AM) is a benign odontogenic tumor with unknown etiology. It is prone to recurrence and has a potential for malignant transformation. Patients often show... (Review)
Review
Ameloblastoma (AM) is a benign odontogenic tumor with unknown etiology. It is prone to recurrence and has a potential for malignant transformation. Patients often show high rates of relapse after curettage, or suffer from structural and functional damage of jaw after partial resection. Whole-genome sequencing data revealed that BRAF mutations and SMO mutations were common and likely to be mutually exclusive in AM. It was also reported that BRAF inhibitors were effective in several patients carrying BRAF mutation. However, reliable preclinical models are urgently needed for exploring targeted therapy as it's so difficult to conduct large clinical trials in this tumor. Patient-derived cell models in vitro and xenograft models in vivo are frequently used preclinical models. In fact, benign tumor cells generally showed a finite proliferative capacity in two-dimensional culture, and most likely, they could exhibit altered cellular phenotype after immortalization. Moreover, this benign tumor presented low chances of subcutaneous engraftment in nude mice. Accordingly, humanized mouse xenograft model needs more exploration. Yet, it is worth mentioning that a three-dimensional organoid model presents a high potential in culturing stem-cell-like epithelial cells in AM, and it would further be used in recapitulating corresponding tumors and developing targeted medicines. In this paper, we review research progress in preclinical models and the genetic variations of AM, and raise drug screening prospect of the current organoid models, which may pave the way for the possible personalized medicine in AM.
Topics: Humans; Animals; Mice; Ameloblastoma; Proto-Oncogene Proteins B-raf; Mice, Nude; Neoplasm Recurrence, Local; Odontogenic Tumors; Mutation
PubMed: 37550047
DOI: 10.3760/cma.j.cn112144-20230703-00264 -
Journal of Oral Pathology & Medicine :... Nov 2023Odontogenic tumors (OT) are composed of heterogeneous lesions, which can be benign or malignant, with different behavior and histology. Within this classification,...
BACKGROUND
Odontogenic tumors (OT) are composed of heterogeneous lesions, which can be benign or malignant, with different behavior and histology. Within this classification, ameloblastoma and ameloblastic carcinoma (AC) represent a diagnostic challenge in daily histopathological practice due to their similar characteristics and the limitations that incisional biopsies represent. From these premises, we wanted to test the usefulness of models based on artificial intelligence (AI) in the field of oral and maxillofacial pathology for differential diagnosis. The main advantages of integrating Machine Learning (ML) with microscopic and radiographic imaging is the ability to significantly reduce intra-and inter observer variability and improve diagnostic objectivity and reproducibility.
METHODS
Thirty Digitized slides were collected from different diagnostic centers of oral pathology in Brazil. After performing manual annotation in the region of interest, the images were segmented and fragmented into small patches. In the supervised learning methodology for image classification, three models (ResNet50, DenseNet, and VGG16) were focus of investigation to provide the probability of an image being classified as class0 (i.e., ameloblastoma) or class1 (i.e., Ameloblastic carcinoma).
RESULTS
The training and validation metrics did not show convergence, characterizing overfitting. However, the test results were satisfactory, with an average for ResNet50 of 0.75, 0.71, 0.84, 0.65, and 0.77 for accuracy, precision, sensitivity, specificity, and F1-score, respectively.
CONCLUSIONS
The models demonstrated a strong potential of learning, but lack of generalization ability. The models learn fast, reaching a training accuracy of 98%. The evaluation process showed instability in validation; however, acceptable performance in the testing process, which may be due to the small data set. This first investigation opens an opportunity for expanding collaboration to incorporate more complementary data; as well as, developing and evaluating new alternative models.
Topics: Humans; Ameloblastoma; Artificial Intelligence; Deep Learning; Reproducibility of Results; Odontogenic Tumors; Carcinoma
PubMed: 37712132
DOI: 10.1111/jop.13481 -
The Journal of Craniofacial SurgeryAmeloblastoma is a benign neoplasm composed of epithelial tissue with invasive and infiltrative behavior at the local level and a high recurrence rate, with various...
BACKGROUND
Ameloblastoma is a benign neoplasm composed of epithelial tissue with invasive and infiltrative behavior at the local level and a high recurrence rate, with various histopathologic patterns and clinical forms. Approximately 85% of conventional ameloblastomas occur in the mandible, most often in the body, angle, and ascending ramus area. The treatment modalities include both conservative and radical treatments. Postoperative follow-up is most important in the treatment of ameloblastoma.
AIMS AND OBJECTIVES
To describe the clinicopathologic profile of mandibular ameloblastoma in patients undergoing different surgical modalities. The primary objective was to describe the clinicopathologic profile and surgical management of mandibular ameloblastoma in patients aged ≥18 years, who had reported to a tertiary dental care center for follow-up during the study period. The secondary objective was to describe the distribution of comorbidities associated with different surgical modalities and reconstructive methods.
SUBJECTS AND METHODS
A total of 34 patients with mandibular ameloblastoma who underwent various surgical modalities between 2011 and 2021 were studied. Information was collected using a predesigned proforma and statistically analyzed.
RESULTS
Thirty-four review cases of ameloblastoma were included in the study. The patients were analyzed concerning age, sex, site, size, clinical presentation, radiographic pattern, histopathologic subtype, type of surgery, and associated comorbidities. Most cases of mandibular ameloblastoma involve the age of 16 to 55 years. The mean age of occurrence was found to be 35.5±13.2. A female preponderance, a tumor size range of 2 to 4 cm, a multicystic variant, involvement of the mandibular body in the premolar-molar area, root resorption, cortical perforation, and a follicular type of histopathologic pattern were the common presentations. Isolated anterior tumors restricted to the incisor/canine region were not found. The common surgical modalities undertaken were conservative methods such as enucleation, and chemical cauterization, and radical methods such as marginal mandibulectomy and segmental resection. Reconstruction using a titanium plate or free fibular graft was performed in the indicated cases. The common comorbidities included difficulty in chewing and loss of facial contour. Recurrence after surgical treatment was rare. Only 9% of cases developed a recurrence within 5 years. No recurrence was noted in cases treated with radical treatment, whereas 50% of cases treated with conservative methods showed recurrence.
CONCLUSION
The age of occurrence, site, and size of the tumor, cortical perforation, root resorption, histopathologic type, and radiographic patterns are widely considered factors in devising a treatment plan for mandibular ameloblastoma. However, there may be rare instances where these tumors behave differently regardless of their innocuous clinicopathologic presentation. Surgical procedures such as segmental resection and marginal mandibulectomy were found to be promising for the eradication of the tumor, and prevention of recurrences and metastasis. However, conservative measures such as enucleation and chemical cauterization were fraught with an increased risk of tumor recurrence and metastasis. Future studies with a larger sample size should focus on the clinicopathologic characteristics of ameloblastoma to elucidate its varied behavior and develop newer and advanced treatment modalities that would provide better surgical and postsurgical outcomes in affected patients.
Topics: Humans; Female; Adolescent; Adult; Young Adult; Middle Aged; Ameloblastoma; Mandibular Neoplasms; Root Resorption; Mandible; Mandibular Osteotomy; Neoplasm Recurrence, Local; Retrospective Studies
PubMed: 37691573
DOI: 10.1097/SCS.0000000000009706 -
Gene May 2024Ameloblastoma (AM), a common odontogenic epithelial tumor, exhibits aggressive growth due to incomplete encapsulation within the jawbone. Postoperative recurrence is a...
OBJECTIVES
Ameloblastoma (AM), a common odontogenic epithelial tumor, exhibits aggressive growth due to incomplete encapsulation within the jawbone. Postoperative recurrence is a significant concern, closely associated with its invasive nature. We investigate the role of tRNA N-7 methylguanosine (mG) modification mediated by Methyltransferase-like 1 (METTL1) in AM's invasive growth and prognosis.
MATERIALS AND METHODS
METTL1 expression was analyzed in diverse cell lines and clinical AM tissues. Its association with postoperative AM recurrence was examined. Functional experiments included METTL1 gene silencing using shRNA in hTERT-AM cells, assessing cell proliferation, migration, and invasion. Xenograft tumor model was constructed to investigate tumor growth. Molecular mechanisms behind METTL1's role in AM invasiveness were elucidated using Ribosome nascent-chain complex-bound mRNA sequencing (RNC-seq) and experimental analysis.
RESULTS
High METTL1 expression was significantly associated with postoperative recurrence in AM. The inhibition of AM development following METTL1 knockdown has been corroborated by experiments conducted both in vitro and in vivo. Analysis of RNC-seq data revealed that downregulated genes were predominantly enriched in the mitogen-activated protein kinase (MAPK) signaling pathway, suggesting that METTL1 may promote AM's invasive growth through the MAPK signaling pathway.
CONCLUSION
Our study elucidates the functional role of METTL1 in AM's invasive development and prognosis. High METTL1 expression is linked to postoperative recurrence, and METTL1 appears to promote AM invasiveness through the MAPK signaling pathway. These findings contribute to a better understanding of AM pathogenesis and may guide future therapeutic strategies.
Topics: Humans; Ameloblastoma; Cell Line; Cell Proliferation; MAP Kinase Signaling System; Methyltransferases
PubMed: 38309318
DOI: 10.1016/j.gene.2024.148234 -
BMC Oral Health Sep 2023The reconstruction of large mandibular defects is a challenge, and free vascularized bone flaps are most commonly used. However, the precision and symmetry of this...
BACKGROUND
The reconstruction of large mandibular defects is a challenge, and free vascularized bone flaps are most commonly used. However, the precision and symmetry of this repair are deficient, and patients have a risk of vascular embolism, flap necrosis, and donor site complications. Therefore, to explore an ideal alternative in mandibular reconstruction with high surgical accuracy and low complications is indispensable.
METHODS
Seven patients with recurrent or large-scope ameloblastoma were enrolled in this study. All patients were provided with a fully digital treatment plan, including the design of osteotomy lines, surgical guides, and three-dimensional printed titanium mesh for implantation. With the assistance of surgical guide, ameloblastomas were resected, and custom 3D printed titanium mesh combined with posterior iliac bone harvest was used in mandibular reconstruction. A comparison was made between the discrepant surgical outcomes and the intended surgical plan, as well as the average three-dimensional deviation of the mandible before and after the surgery. At the same time, the resorption rate of the implanted bone was evaluated.
RESULTS
All patients completed the fully digital treatment process successfully without severe complications. Image fusion showed that the postoperative contour of the mandible was basically consistent with surgical planning, except for a slight increase in the inferior border of the affected side. The mean three-dimensional deviation of the mandible between the preoperative and postoperative periods was 0.78 ± 0.41 mm. The mean error between the intraoperative bone volume and the digital planning bone volume was 2.44%±2.10%. Furthermore, the bone resorption rates of the harvested graft 6 months later were 32.15%±6.95%.
CONCLUSIONS
The use of digital surgical planning and 3D-printed templates can assist surgeons in performing surgery precisely, and the 3D-printed titanium mesh implant can improve the patient's facial symmetry. 3D printed titanium mesh combined with posterior iliac cancellous bone graft can be regarded as an ideal alternative in extensive mandibular reconstruction.
Topics: Humans; Ameloblastoma; Titanium; Cancellous Bone; Surgical Mesh; Dental Implants; Mandible
PubMed: 37730602
DOI: 10.1186/s12903-023-03386-0 -
Frontiers in Veterinary Science 2024Ameloblastoma in dogs most often has a highly conserved acanthomatous cell morphology and is recognized as canine acanthomatous ameloblastoma (CAA) while conventional...
Ameloblastoma in dogs most often has a highly conserved acanthomatous cell morphology and is recognized as canine acanthomatous ameloblastoma (CAA) while conventional ameloblastoma (CA) makes up a smaller yet morphologically diverse group of epithelial odontogenic tumors. In humans, a rare desmoplastic histological subtype has distinctive clinical, radiological, and microscopic features. Desmoplastic ameloblastoma (DA) has not previously been described in dogs, although it has been rarely referenced in the veterinary literature. This is the first thorough description of a case series of DA in dogs and describes clinical presentation, diagnostic imaging findings, histopathological features for diagnosis, and treatment outcome. Clinically, DA most often presents as a mass or swelling in the rostral mandible or maxilla of middle age to older dogs. On diagnostic imaging, the lesion has a radiolucent or mixed pattern with well-defined borders and variable loculation. As a solid, fibrous tumor with obscured odontogenic epithelium, DA is challenging to diagnose histologically and can mimic several other oral tumors, both benign and malignant. As an ameloblastoma, the biological behavior of DA is locally destructive yet benign and prognosis is favorable following surgical excision.
PubMed: 38638641
DOI: 10.3389/fvets.2024.1362237 -
Journal of Oral Pathology & Medicine :... Nov 2023This review aims to analyse the recurrence rate in BRAFv600e+ and BRAFv600e- ameloblastomas and explore its association with clinicopathological variables. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
This review aims to analyse the recurrence rate in BRAFv600e+ and BRAFv600e- ameloblastomas and explore its association with clinicopathological variables.
METHODS
A comprehensive search was conducted using databases including PubMed, Embase, Cochrane Central Register of Controlled Trials, Clinicaltrials.gov, Google Scholar and grey literature, without any limitation on start date or language up to 20 June 2023. A random effect meta-analysis was conducted and Metaregression analyses were performed based on available clinicopathological factors.
RESULTS
Fifteen studies met the criteria for meta-analysis of outcomes. There was no significant difference in overall recurrence rates between the two groups (risk difference = 0.001, p-value = 0.987). Increasing male:female ratio in the BRAFv600e+ group was associated with a lower reported recurrence, suggesting a higher recurrence rate in females. The odds of having mandibular lesion were four times higher in BRAFv600e+ cases compared to BRAFv600e- cases (confidence interval: 2.121-7.870, p < 0.001, I = 28.37%).
CONCLUSION
Within the BRAFv600e+ group, females showed a higher reported recurrence rate. This specific clinical group may benefit from BRAFv600e mutation investigation and potential upscaled surgical treatment and additional BRAF inhibitor therapy, which needs validation in future studies.
Topics: Humans; Male; Female; Ameloblastoma; Proto-Oncogene Proteins B-raf; Mutation; Molecular Targeted Therapy
PubMed: 37872712
DOI: 10.1111/jop.13494 -
Biomedical Reports Apr 2024Ameloblastoma (AM) is a prominent benign odontogenic tumor characterized by aggressiveness, likely originating from tooth-generating tissue or the dental follicle (DF)....
Ameloblastoma (AM) is a prominent benign odontogenic tumor characterized by aggressiveness, likely originating from tooth-generating tissue or the dental follicle (DF). However, proteomic distinctions between AM and DF remain unclear. In the present study, the aim was to identify the distinction between AM and DF in terms of their proteome and to determine the associated hub genes. Shotgun proteomics was used to compare the proteomes of seven fresh-frozen AM tissues and five DF tissues. Differentially expressed proteins (DEPs) were quantified and subsequently analyzed through Gene Ontology-based functional analysis, protein-protein interaction (PPI) analysis and hub gene identification. Among 7,550 DEPs, 520 and 216 were exclusive to AM and DF, respectively. Significant biological pathways included histone H2A monoubiquitination and actin filament-based movement in AM, as well as pro-B cell differentiation in DF. According to PPI analysis, the top-ranked upregulated hub genes were ubiquitin C (UBC), breast cancer gene 1 (BRCA1), lymphocyte cell-specific protein-tyrosine kinase (LCK), Janus kinase 1 and ATR serine/threonine kinase, whereas the top-ranked downregulated hub genes were UBC, protein kinase, DNA-activated, catalytic subunit (PRKDC), V-Myc avian myelocytomatosis viral oncogene homolog (MYC), tumor protein P53 and P21 (RAC1) activated kinase 1. When combining upregulated and downregulated genes, UBC exhibited the highest degree and betweenness values, followed by MYC, BRCA1, PRKDC, embryonic lethal, abnormal vision, Drosophila, homolog-like 1, myosin heavy chain 9, amyloid beta precursor protein, telomeric repeat binding factor 2, LCK and filamin A. In summary, these findings contributed to the knowledge on AM protein profiles, potentially aiding future research regarding AM etiopathogenesis and leading to AM prevention and treatment.
PubMed: 38476605
DOI: 10.3892/br.2024.1752 -
BMC Oral Health Dec 2023Ameloblastoma (AM), the benign counterpart of ameloblastic carcinoma, is a benign odontogenic tumor of epithelial origin, naturally aggressive, with unlimited growth...
BACKGROUND
Ameloblastoma (AM), the benign counterpart of ameloblastic carcinoma, is a benign odontogenic tumor of epithelial origin, naturally aggressive, with unlimited growth potential and a high tendency to relapse if not adequately removed. Patients with AM treated surgically can benefit from dental implant therapy, promoting oral rehabilitation and improving their quality of life. The present study aimed to determine the survival rate of dental implants placed after surgical treatment of patients affected by AM. In addition, there were two secondary objectives: 1) To evaluate which dental implant loading protocols are most frequently used and 2) To determine the type of prosthetic restoration most commonly used in these patients.
METHODS
The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines were followed during the study. Searches were performed in three databases (PubMed/MEDLINE, Scopus, and Google Scholar) until November 2023. Additionally, the electronic search was enriched by an iterative hand search of journals related to oral pathology and medicine, maxillofacial surgery, and oral prosthodontics and implantology. Only reports and case series in English from January 2003 to date were included. The Joanna Briggs Institute tool (JBI-Case Reports/Case Series) was used for the study quality assessment.
RESULTS
The total number of patients and implants studied were 64 and 271, respectively, all with surgically treated AM. The patient's ages ranged from 8 to 79 years, with a mean (SD) age of 37.3 ± 16.4. Fifty-three percent were male and 47% were female. The range of follow-up duration was 1 to 22 years. An implant survival/success rate of 98.1% was reported. In addition, most of them were conventionally loaded (38.3%). Hybrid implant-supported fixed dentures were the most commonly used by prosthodontists (53%).
CONCLUSIONS
Oral rehabilitation with dental implants inserted in free flaps for orofacial reconstruction in surgically treated patients with AM can be considered a safe and successful treatment modality.
Topics: Adolescent; Adult; Aged; Child; Female; Humans; Male; Middle Aged; Young Adult; Ameloblastoma; Dental Implantation, Endosseous; Dental Implants; Dental Prosthesis, Implant-Supported; Dental Restoration Failure; Neoplasm Recurrence, Local; Odontogenic Tumors; Quality of Life; Treatment Outcome
PubMed: 38110933
DOI: 10.1186/s12903-023-03765-7 -
Journal of Oral Pathology & Medicine :... Sep 2023The objective of this systematic review with meta-analysis was to critically evaluate the available data on the association of the BRAF V600E mutation and recurrence... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
The objective of this systematic review with meta-analysis was to critically evaluate the available data on the association of the BRAF V600E mutation and recurrence rate of ameloblastomas.
MATERIALS AND METHODS
This systematic review was registered in Prospero (CRD42020183645) and performed based on the PRISMA statement. A comprehensive search in PubMed, Web of Science, Scopus and Cochrane Library databases was performed in order to answer the question "Does BRAF V600E mutation affect recurrence rate of ameloblastomas?" Methodological quality and risk of bias of the selected studies were assessed with JBI Critical Appraise Tool. Meta-analysis of quantitative data was conducted with RevMan 5.3 and Jamovi 2.3.
RESULTS
The initial search identified 302 articles, and 21 met the inclusion criteria. A total of 855 subjects with ameloblastoma were included in the analysis. The pooled measures for frequency of BRAF V600E mutation was 65.30% (95% CI: 0.56-0.75; p < .001; I = 90.85%; τ = 0.205; p < .001), and the pooled recurrence rate was 25.30% (95% CI: 0.19-0.31; p < .001; I = 79.44%; τ = 0.118; p < .001). No differences in recurrence rate were observed between the BRAF V600E and wild type BRAF ameloblastomas, with a pooled Odds Ratio of 0.93 (95% CI: 0.56-1.54; p = .78; I = 31%; p = .09).
CONCLUSIONS
BRAF V600E mutation is a frequent event in ameloblastomas, but does not increase nor reduce its recurrence rate, and thus have a limited value in predicting its prognosis.
Topics: Humans; Ameloblastoma; Proto-Oncogene Proteins B-raf; Mutation; Prognosis
PubMed: 37364158
DOI: 10.1111/jop.13458