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PloS One 2015Ameloblastoma is the second most common odontogenic tumor, known to be slow-growing, persistent, and locally aggressive. Recent data suggests that ameloblastoma is best... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Ameloblastoma is the second most common odontogenic tumor, known to be slow-growing, persistent, and locally aggressive. Recent data suggests that ameloblastoma is best treated with wide resection and adequate margins. Following primary excision, bony reconstruction is often necessary for a functional and aesthetically satisfactory outcome, making early diagnosis paramount. Despite earlier diagnosis potentially limiting the extent of resection and reconstruction, an understanding of the growth rate and natural history of ameloblastoma has been notably lacking from the literature.
METHOD
A systematic review of the literature was conducted by reviewing relevant articles from PubMed and Web of Science databases. Each article's level of evidence was formally appraised according to the Centre of Evidence Based Medicine (CEBM), with data from each utilized in a meta-analysis of growth rates for ameloblastoma.
RESULTS
Literature regarding the natural history of ameloblastoma is limited since the tumor is immediately acted upon at its initial detection, unless the patient voluntarily refuses a surgical intervention. From the limited data, it is derived that the highest estimated growth rate is associated with solid, multicystic type and the lowest rate with peripheral ameloblastomas. After meta-analysis, the calculated mean specific grow rate is 87.84% per year.
CONCLUSION
The growth rate of ameloblastoma has been demonstrated, offering prognostic and management information, particularly in cases where a delay in management is envisaged.
Topics: Adult; Aged; Ameloblastoma; Female; Humans; Jaw Neoplasms; Male; Middle Aged; Young Adult
PubMed: 25706407
DOI: 10.1371/journal.pone.0117241 -
Head and Neck Pathology Jun 2023The World Health Organization's (WHO) chapter on odontogenic and maxillofacial bone tumors provides a global reference for diagnosis of these tumors. In the fifth... (Review)
Review
Proceedings of the 2023 North American Society of Head and Neck Pathology Companion Meeting, New Orleans, LA, March 12, 2023: Odontogenic Tumors: Have We Achieved an Evidence-Based Classification.
BACKGROUND
The World Health Organization's (WHO) chapter on odontogenic and maxillofacial bone tumors provides a global reference for diagnosis of these tumors. In the fifth edition, the inclusion of consensus definitions and development of essential and desirable diagnostic criteria help improve recognition of distinct entities. These are key enhancements since the diagnosis of odontogenic tumors is largely based on histomorphology which is taken in combination with clinical and radiographic appearances.
METHODS
Review.
RESULTS
Despite delineation of diagnostic criteria for ameloblastoma, adenoid ameloblastoma, and dentinogenic ghost cell tumor, a subset of these tumors continues to show overlapping histological features that can potentially lead to misdiagnosis. Accurate classification may be challenging on small biopsies, but potentially enhanced by refining existing diagnostic criteria and utilization of immunohistochemistry and/or molecular techniques in a specific cases. It has become clear that the clinical and histologic features of the non-calcifying Langerhans cell-rich subtype of calcifying epithelial odontogenic tumor and the amyloid-rich variant of odontogenic fibroma converge into a single tumor description. In addition, this tumor shows remarkable clinical, histological overlap with a subset of sclerosing odontogenic carcinoma located in the maxilla. Benign perineural involvement vs perineural invasion is an underexplored concept in odontogenic neoplasia and warrants clarification to reduce diagnostic confusion with sclerosing odontogenic carcinoma.
CONCLUSION
While controversial issues surrounding classification and discrete tumor entities are addressed in the WHO chapter, ambiguities inevitably remain. This review will examine several groups of odontogenic tumors to highlight persistent knowledge gaps, unmet needs and unresolved controversies.
Topics: Humans; Ameloblastoma; New Orleans; Odontogenic Tumors; Mouth Neoplasms; Carcinoma
PubMed: 37278887
DOI: 10.1007/s12105-023-01561-x -
Clinical and Experimental Dental... Feb 2021Ameloblastoma is a benign, locally aggressive odontogenic tumor with high recurrence rates. Matrix metalloproteinases (MMPs) mediate extracellular integrity in normal...
OBJECTIVES
Ameloblastoma is a benign, locally aggressive odontogenic tumor with high recurrence rates. Matrix metalloproteinases (MMPs) mediate extracellular integrity in normal and pathological conditions, and exert multiple functions coordinating inflammation and tumor progression. E-cadherin and beta-catenin are adherence junction molecules in cell-to-cell connections. We investigated the involvement of MMP-7, -8, -9, E-cadherin, and beta-catenin in ameloblastoma and the surrounding extracellular matrix.
MATERIAL AND METHODS
Our material consisted of 30-34 tissue samples from ameloblastoma patients of Helsinki University Hospital. We used immunohistochemistry to detect the expression of the biomarkers. Two oral pathologists independently scored the immunoexpression intensities and statistical calculations were made based on the results.
RESULTS
E-cadherin expression was weaker in the maxillary than in mandibular ameloblastomas. Beta-catenin was expressed in the ameloblastoma cell membranes. We detected MMP-8 and -9 expression in polymorphonuclear neutrophils in the extracellular area and these MMPs correlated positively with each other. Osteoclasts lining bone margins and multinuclear giant cells expressed MMP-9. Neither MMP-8 nor MMP-9 immunoexpression could be detected in ameloblastoma cells. MMP-7 expression was seen in some apoptotic cells.
CONCLUSION
The fact that E-cadherin immunoexpression was weaker in maxillary compared to mandibular ameloblastomas might associate to earlier recurrences. It promotes the idea of mandibular and maxillary ameloblastoma exerting differences in their biologies. We detected MMP-8 and -9 in polymorphonuclear neutrophils which relates to these MMPs participating in extracellular remodeling through a mild inflammatory process. Bone degradation around ameloblastoma may be due to MMP-9 in osteoclasts but this phenomenon might be an independent process and needs further investigations.
Topics: Ameloblastoma; Cadherins; Humans; Matrix Metalloproteinase 7; Matrix Metalloproteinase 8; Matrix Metalloproteinase 9; beta Catenin
PubMed: 32985799
DOI: 10.1002/cre2.331 -
Oncotarget Jan 2017Ameloblastoma of the jaws remains the top difficult to treat odontogenic tumour and has a high recurrence rate. New evidence suggests that non-coding RNAs (ncRNAs) play...
Ameloblastoma of the jaws remains the top difficult to treat odontogenic tumour and has a high recurrence rate. New evidence suggests that non-coding RNAs (ncRNAs) play a critical role in tumourgenesis and prognosis of cancer. However, ameloblastoma ncRNA expression data is lacking. Here we present the first report of ameloblastoma ncRNA signatures. A total of 95 ameloblastoma cases and a global array transcriptome technology covering > 285.000 full-length transcripts were used in this two-step analysis. The analysis first identified in a test cohort 31 upregulated ameloblastoma-associated ncRNAs accompanied by signalling pathways of cancer, spliceosome, mRNA surveillance and Wnt. Further validation in an independent cohort points out the long non-coding (lncRNAs) and small nucleolar RNA (snoRNAs): LINC340, SNORD116-25, SNORA11, SNORA21, SNORA47 and SNORA65 as a distinct ncRNA signature of ameloblastoma. Importantly, the presence of these ncRNAs was independent of BRAF-V600E and SMO-L412F mutations, histology type or tumour location, but was positively correlated with the tumour size. Taken together, this study shows a systematic investigation of ncRNA expression of ameloblastoma, and illuminates new diagnostic and therapeutic targets for this invasive odontogenic tumour.
Topics: Adult; Aged; Ameloblastoma; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Gene Regulatory Networks; Humans; Jaw Neoplasms; Male; Middle Aged; Oligonucleotide Array Sequence Analysis; RNA, Untranslated; Signal Transduction
PubMed: 27965463
DOI: 10.18632/oncotarget.13889 -
Cureus Nov 2022Ameloblastomas are true benign tumors of odontogenic epithelial origin mostly seen in the mandible. After odontoma, it is the second most commonly seen odontogenic...
Ameloblastomas are true benign tumors of odontogenic epithelial origin mostly seen in the mandible. After odontoma, it is the second most commonly seen odontogenic neoplasm. Ameloblastomas comprise several clinical, radiological, and histological varieties, making them the most significant odontogenic neoplasm. Unicystic ameloblastomas (UAs) refer to those cystic lesions that show clinical, radiographic, or gross features of jaw cysts but on histologic examination, they show a typical ameloblastomatous epithelium lining the cysts' cavities, with or without luminal and/or mural tumor proliferation. UAs are a less encountered variant of ameloblastomas and are believed to be less aggressive. As this tumor shows considerable similarities with dentigerous cysts, both clinically and radiographically the biological behavior of this tumor group was reviewed.
PubMed: 36475180
DOI: 10.7759/cureus.31039 -
Journal of Cancer Research and... 2020Altered molecular signaling pathways in ameloblastoma have been identified to play a pivotal role in the mechanism of oncogenesis, differentiation, and tumor...
BACKGROUND
Altered molecular signaling pathways in ameloblastoma have been identified to play a pivotal role in the mechanism of oncogenesis, differentiation, and tumor progression. Phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin pathway is one of the signaling pathways that are associated with the pathogenesis of ameloblastoma. Phosphatase and tensin homolog (PTEN) controls cell migration and proliferation. It monitors the level of the Akt and maintains cellular integrity. The present study was aimed to study the immunoexpression of PTEN in ameloblastoma to understand its role in the pathogenesis of ameloblastoma.
MATERIALS AND METHODS
Twenty cases of ameloblastoma and ten cases of normal tooth germ were subjected to immunohistochemical staining against PTEN.
RESULTS
Strong PTEN immunopositivity was seen in the tooth germs, while weak positivity was seen in the ameloblastoma. The immunoscore for PTEN was calculated by adding the percentage score and the intensity score. Seventeen cases showed the reduced PTEN expression in the epithelial component of ameloblastoma. The unpaired t-test showed a statistically significant difference in the mean PTEN immunoscore in tooth germ and ameloblastoma.
CONCLUSION
The study showed reduced PTEN immunoreactivity, which plays a role in the pathogenesis of ameloblastoma, through Akt pathway.
Topics: Adolescent; Adult; Aged; Ameloblastoma; Biomarkers, Tumor; Case-Control Studies; Cell Differentiation; Female; Humans; Immunohistochemistry; Infant; Jaw Neoplasms; Male; Middle Aged; PTEN Phosphohydrolase; Proto-Oncogene Proteins c-akt; Signal Transduction; Young Adult
PubMed: 32719259
DOI: 10.4103/jcrt.JCRT_528_18 -
The British Journal of Oral &... Jan 2021Ameloblastoma is the most common benign, but locally destructive, epithelial odontogenic tumour. Peripheral ameloblastoma may involve soft tissues without invasion or... (Review)
Review
Ameloblastoma is the most common benign, but locally destructive, epithelial odontogenic tumour. Peripheral ameloblastoma may involve soft tissues without invasion or involvement of bone. The aim of this structured review was to evaluate the literature and guide clinical management. Three online databases were searched for relevant studies: Medline, EMBASE, and Ovid Evidence-Based Medicine, and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. A total of 520 papers were initially identified, and after exclusions were applied, 45 were included. Conservative surgical excision was the treatment of choice. There was no consensus in relation to the extent of the surgical margins required. The management of peripheral ameloblastoma appears to favour conservative excision with narrow margins of normal tissue. Follow up of at least 10 years is recommended to monitor for recurrence.
Topics: Ameloblastoma; Bone and Bones; Humans; Margins of Excision; Neoplasm Recurrence, Local; Odontogenic Tumors
PubMed: 33162201
DOI: 10.1016/j.bjoms.2020.08.084 -
International Journal of Computer... Mar 2021The differentiation of the ameloblastoma and odontogenic keratocyst directly affects the formulation of surgical plans, while the results of differential diagnosis by...
PURPOSE
The differentiation of the ameloblastoma and odontogenic keratocyst directly affects the formulation of surgical plans, while the results of differential diagnosis by imaging alone are not satisfactory. This paper aimed to propose an algorithm based on convolutional neural networks (CNN) structure to significantly improve the classification accuracy of these two tumors.
METHODS
A total of 420 digital panoramic radiographs provided by 401 patients were acquired from the Shanghai Ninth People's Hospital. Each of them was cropped to a patch as a region of interest by radiologists. Furthermore, inverse logarithm transformation and histogram equalization were employed to increase the contrast of the region of interest (ROI). To alleviate overfitting, random rotation and flip transform as data augmentation algorithms were adopted to the training dataset. We provided a CNN structure based on a transfer learning algorithm, which consists of two branches in parallel. The output of the network is a two-dimensional vector representing the predicted scores of ameloblastoma and odontogenic keratocyst, respectively.
RESULTS
The proposed network achieved an accuracy of 90.36% (AUC = 0.946), while sensitivity and specificity were 92.88% and 87.80%, respectively. Two other networks named VGG-19 and ResNet-50 and a network trained from scratch were also used in the experiment, which achieved accuracy of 80.72%, 78.31%, and 69.88%, respectively.
CONCLUSIONS
We proposed an algorithm that significantly improves the differential diagnosis accuracy of ameloblastoma and odontogenic keratocyst and has the utility to provide a reliable recommendation to the oral maxillofacial specialists before surgery.
Topics: Algorithms; Ameloblastoma; China; Diagnosis, Differential; Humans; Machine Learning; Neural Networks, Computer; Odontogenic Cysts; Radiography; Radiography, Panoramic; Radiologists; Reproducibility of Results; Rotation; Sensitivity and Specificity
PubMed: 33547985
DOI: 10.1007/s11548-021-02309-0 -
International Journal of Clinical and... 2018Ameloblastoma shows invasive growth and is susceptible to recurrence. This study aimed to detect the expression of E-Cadherin, Vimentin and β-Catenin (proteins related...
OBJECTIVE
Ameloblastoma shows invasive growth and is susceptible to recurrence. This study aimed to detect the expression of E-Cadherin, Vimentin and β-Catenin (proteins related to epithelial mesenchymal transformation (EMT) in the ameloblastoma and to explore association with clinicopathological characteristics of ameloblastoma.
METHODS
Immunohistochemistry was employed to detect the protein expression of E-Cadherin, Vimentin and β-Catenin in the ameloblastoma, and its association with clinicopathological characteristics of ameloblastoma was further evaluated.
RESULTS
E-Cadherin expression was reduced or absent on the membrane of the peripheral columnar and cubic epithelial cells; Vimentin expression was high in the interstitium as well as epithelial cells in ameloblastoma; E-Cadherin expression was negatively related to Vimentin expression. β-catenin expression on the membrane of ameloblastoma epithelial cells reduced, but its ectopic expression was observed in the cytoplasm and/or nucleus.
CONCLUSION
EMT related proteins E-Cadherin, β-catenin and Vimentin are involved in the occurrence and development of ameloblastoma and these proteins can be used as biomarkers of invasiveness of ameloblastoma.
PubMed: 31938101
DOI: No ID Found -
Journal of Dental Research Nov 2022Ameloblastoma (AB) is an odontogenic tumor that arises from ameloblast-lineage cells. Although relatively uncommon and rarely metastatic, AB tumors are locally invasive...
Ameloblastoma (AB) is an odontogenic tumor that arises from ameloblast-lineage cells. Although relatively uncommon and rarely metastatic, AB tumors are locally invasive and destructive to the jawbone and surrounding structures. Standard-of-care surgical resection often leads to disfigurement, and many tumors will locally recur, necessitating increasingly challenging surgeries. Recent genomic studies of AB have uncovered oncogenic driver mutations, including in the mitogen-activated protein kinase (MAPK) and Hedgehog signaling pathways. Medical therapies targeting those drivers would be a highly desirable alternative or addition to surgery; however, a paucity of existing AB cell lines has stymied clinical translation. To bridge this gap, here we report the establishment of 6 new AB cell lines-generated by "conditional reprogramming"-and their genomic characterization that reveals driver mutations in FGFR2, KRAS, NRAS, BRAF, PIK3CA, and SMO. Furthermore, in proof-of-principle studies, we use the new cell lines to investigate AB oncogene dependency and drug sensitivity. Among our findings, AB cells with KRAS or NRAS mutation (MAPK pathway) are exquisitely sensitive to MEK inhibition, which propels ameloblast differentiation. AB cells with activating SMO-L412F mutation (Hedgehog pathway) are insensitive to vismodegib; however, a distinct small-molecule SMO inhibitor, BMS-833923, significantly reduces both downstream Hedgehog signaling and tumor cell viability. The novel cell line resource enables preclinical studies and promises to speed the translation of new molecularly targeted therapies for the management of ameloblastoma and related odontogenic neoplasms.
Topics: Humans; Ameloblastoma; Hedgehog Proteins; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins p21(ras); Neoplasm Recurrence, Local; Odontogenic Tumors; Class I Phosphatidylinositol 3-Kinases; Mitogen-Activated Protein Kinases; Mitogen-Activated Protein Kinase Kinases; Cell Line
PubMed: 35689405
DOI: 10.1177/00220345221100773