Comprehensive Genomic Analysis of Cemento-Ossifying Fibroma.

Cemento-ossifying fibroma (COF) of the jaws is currently classified as a benign mesenchymal odontogenic tumor, and only targeted approaches have been used to assess its genetic alterations. A minimal proportion of COFs harbor CDC73 somatic mutations, and copy number alterations (CNAs) involving chromosomes 7 and 12 have recently been reported in a small proportion of cases. However, the genetic background of COFs remains obscure. We used a combination of whole-exome sequencing and RNA sequencing to assess somatic mutations, fusion transcripts, and CNAs in a cohort of 12 freshly collected COFs. No recurrent fusions have been identified among the 5 cases successfully analyzed by RNA sequencing, with in-frame fusions being detected in 2 cases (MARS1::GOLT1B and PARG::BMS1 in one case and NCLN::FZR1 and NFIC::SAMD1 in the other case) and no candidate fusions identified for the remaining 3 cases. No recurrent pathogenic mutations were detected in the 11 cases that had undergone whole-exome sequencing. A KRAS p.L19F missense variant was detected in one case, and 2 CDC73 deletions were detected in another case. The other variants were of uncertain significance and included variants in PC, ACTB, DOK6, HACE1, and COL1A2 and previously unreported variants in PTPN14, ATP5F1C, APOBEC1, HDAC5, ATF7IP, PARP2, and ACTR3B. The affected genes do not clearly converge on any signaling pathway. CNAs were detected in 5/11 cases (45%), with copy gains involving chromosome 12 occurring in 3/11 cases (27%). In conclusion, no recurrent fusions or pathogenic variants have been detected in the present COF cohort, with copy gains involving chromosome 12 occurring in 27% of cases.

A conservative approach for unicystic ameloblastoma: Retrospective clinic-pathologic analysis of 12 cases.

BACKGROUND: Unicystic ameloblastoma is an encapsulated odontogenic neoplasm with a single cyst cavity. The conservative or aggressive surgical approaches used to treat the tumor directly affect recurrence rates. However, there is a lack of a standard protocol that can guide its management. STUDY DESIGN: We retrospectively reviewed the clinicopathological findings and therapeutical procedures of 12 unicystic ameloblastoma cases treated by the same surgeon during the past 20 years. METHODS: All cases of unicystic ameloblastoma diagnosed by biopsy and treated by the same surgeon between 2002 and 2022 were reviewed. Eligibility criteria were patients with completely filled-out charts containing the follow-up period and confirmation of the diagnoses based on the microscopic findings of the whole excised specimens. Data collected were categorized into clinical, radiographic, histological, surgical, and recurrence aspects. RESULTS: There was a female predilection (2:1), and ages ranged between 18 and 61 years (mean: 27.25, ±12.45). Almost all (92%) affected the posterior mandible. Radiographically, the mean length of the lesions was 46.14 mm ± 14.28 mm which 92% were unilocular and 8.3% multilocular. Root resorption (n = 7, 58%), tooth displacement (n = 9, 75%), and cortical perforation (n = 5, 42%) were also observed. The mural histological subtype corresponded to 9 (75%) of the cases. The same conservative protocol was performed in all cases. The follow-up period ranged between 12 and 240 months (~62 ± 65) and recurrence occurred in only one patient (8%). CONCLUSION: Our findings suggest a conservative approach should be the first option for unicystic ameloblastoma treatment, even for those with mural proliferation.

Central giant cell granulomas of the jaws stromal cells harbour mutations and have osteogenic differentiation capacity, in vivo and in vitro.

BACKGROUND: Central giant cell granulomas (CGCG) of the jaws are osteolytic lesions that may behave aggressively and respond poorly to surgery. Microscopically, in addition to giant cells, there is a mononuclear cell population composed of macrophage/monocytic cells and spindle-shaped cells of mesenchymal origin. Seventy two percent of these tumours harbour mutually exclusive TRPV4, KRAS and FGFR1 mutations. We aimed to assess the mutational status of mononuclear and giant cells and the osteogenic potential of stromal cells in vitro and in vivo. METHODS AND RESULTS: We screened CGCG for signature mutations and used laser-capture microdissection to demonstrate that the mutations are restricted to the mononuclear cells. Additionally, we established CGCG primary cell culture and observed that the cells retained the mutations throughout passages. By flow cytometry, we observed predominance of CD14- CD51- CD61- cells, consistent with the expected profile for stromal cells. Considering the mesenchymal origin of stromal cells, we assessed the osteogenic differentiation potential of CGCG cells in culture by cytochemistry (von Kossa and alizarin red staining), alkaline phosphatase (ALP) activity assay and gene expression of osteogenic markers. CGCG cells presented self-capacity to increase ALP levels in a time-dependent manner and under osteogenic induction presented increasing number of calcium deposits, and overall higher expression of osteocalcin, RUNX2, ALPL and osteopontin than cells without osteogenic induction. A patient-derived xenograft model for CGCG was established, and osteoid material deposition was observed. CONCLUSION: Collectively, the results confirm that the signature mutations are restricted to stromal cells in CGCG, and the in vitro and in vivo results support that these cells have the capacity to differentiate into osteoblasts, in line with the bone formation often observed in the stroma of these lesions.

Unveiling metabolic changes in marsupialized odontogenic keratocyst: A pilot study.

OBJECTIVE: We aimed to assess which metabolic pathways would be implicated in the phenotypic changes of the epithelial lining of odontogenic keratocyst after marsupialization, comparing pre- and post-marsupialized lesions with adjacent oral mucosa. MATERIALS AND METHODS: Eighteen formalin-fixed and paraffin-embedded tissues from six subjects were divided into three paired groups: odontogenic keratocyst pre- (n = 6) and post-marsupialization (n = 6), and adjacent oral mucosa (n = 6). The metabolic pathways found in these groups were obtained by high-performance liquid chromatography-mass spectrometry-based untargeted metabolomics performed. RESULTS: Through putative metabolite annotation followed by pathway enrichment and predictive analysis with automated algorithms (Mummichog and Gene Set Enrichment Analysis), we found differences in many cellular processes that may be involved in inflammation, oxidative stress response, keratinocyte-basal membrane attachment, differentiation, and proliferation functions, all relevant to odontogenic keratocyst pathobiology and the phenotype acquired after marsupialization. CONCLUSION: Our study was able to identify several metabolic pathways potentially involved in the metaplastic changes induced by marsupialization of odontogenic keratocysts. An improved comprehension of this process could pave the way for the development of targeted therapies.

BRAF p.V600E status in epithelial areas of ameloblastoma with different histological aspects: Implications to the clinical practice.

BACKGROUND: BRAF p.V600E is reported in up to 80% of ameloblastomas. Despite the high frequency, the presence of this mutation in different histopathological areas of the tumour has not been investigated. This information has an important role in the use of BRAF p.V600E assessment as an auxiliary tool in the differential diagnosis between unicystic ameloblastoma and other odontogenic cystic lesions, especially when only incisional biopsies are available. Therefore, the purpose of the present study was to investigate BRAF p.V600E heterogeneity in unicystic ameloblastoma. METHODS: Five cases of ameloblastoma and two dentigerous cysts were analysed. The regions exhibiting different microscopic characteristics were selected from each ameloblastoma case and manually dissected. TaqMan allele-specific qPCR or Sanger sequencing was performed to determine BRAF p.V600E status. RESULTS: We screened the mutation in a small cohort of UA and no molecular heterogeneity was found. Four cases of ameloblastoma (80%) exhibited BRAF p.V600E in all different areas evaluated. One case did not harbour the mutation in any microscopic region analysed. The BRAF mutation was absent in the dentigerous cysts. CONCLUSION: Ameloblastomas appear to exhibit a homogeneous profile regarding the BRAF p.V600E no matter what histological feature is observed under light microscopy, suggesting that this molecular test may contribute to establish the correct diagnosis in cases microscopically resembling other odontogenic lesions.

First insights for targeted therapies in odontogenic myxoma.

OBJECTIVE: Odontogenic myxoma (OM) occasionally responds poorly to surgical treatment. The MAPK pathway is constitutively activated in several neoplasms and we aimed to test if the MAPK pathway is activated in OM, in order to pave the way for an alternative therapy for aggressive and recurrent cases. MATERIALS AND METHODS: The immunoexpression of phosphorylated ERK1/2 (pERK1/2) was assessed in OM. We established a 3D organotypic culture model for the in vitro study and patient-derived xenografts (PDX) in mice for the in vivo study. The MEK inhibitor U0126 was used to inhibit phosphorylation of ERK1/2 in the in vitro and in vivo models. RESULTS: All OM showed strong pERK1/2 immunoexpression, consistent with MAPK pathway activation. Treatment of the 3D culture with U0126 resulted in a reduced pERK1/2/ERK1/2 ratio. Consistent with the in vitro results, all PDX of animals treated with U0126 showed a decreased volume fold change compared with controls. CONCLUSIONS: The MAPK pathway is activated in OM and its inhibition leads to tumor shrinkage in PDX and cell culture models. CLINICAL RELEVANCE: Our results offer a pre-clinical frame for OM-targeted therapy. Further work is needed to determine if this initial finding holds clinical promise.

Bringing benign ectomesenchymal odontogenic tumours to the lab: An in vitro study using an organotypic culture model.

BACKGROUND: Benign neoplasms exhibit most of the cellular phenomena considered hallmarks of cancer, except the capacity to metastasize. Thus, the elucidation of the mechanisms associated with the progression of benign neoplasms may complement and clarify the mechanisms involved in carcinogenesis. Benign odontogenic tumours often result in facial deformities and morbidities, and have complex pathogenesis, mainly due to the diversity of interactions between the odontogenic epithelium and the ectomesenchyme. Primary cell culture of such tumours is not only difficult to be established and maintained, but also tumour cells lose characteristic cellular morphology. Considering gene expression, growth, migration, proliferation and cellular morphology are controlled by cell-cell interactions and cell-extracellular matrix interactions, cell culture in 3D substrates has gained space as a way to overcome some of the limitations of traditional monolayer cell culture systems. METHODS: In this study, fragments obtained from mesenchymal odontogenic tumours were cultured in type I collagen scaffolds. Invasion tests were performed in these models, as well as phenotypic characterization of the cultured tumours. RESULTS: The results obtained for the odontogenic myxoma and the cemento-ossifying fibroma demonstrate a good reproduction of the growth pattern of these tumours under ex vivo conditions. Microscopic evaluation showed maintenance of cell viability in the explants for more than 30 days, without the presence of necrosis. CONCLUSION: This is the first study involving long-term 3D primary cultures of benign odontogenic tumours, which is expected to support complex approaches to cell and molecular biology, and to serve as an experimental model for testing molecular therapies.

MicroRNA profiling reveals dysregulated microRNAs and their target gene regulatory networks in cemento-ossifying fibroma.

BACKGROUND: Cemento-ossifying fibroma (COF) is a benign fibro-osseous neoplasm of uncertain pathogenesis, and its treatment results in morbidity. MicroRNAs (miRNA) are small non-coding RNAs that regulate gene expression and may represent therapeutic targets. The purpose of the study was to generate a comprehensive miRNA profile of COF compared to normal bone. Additionally, the most relevant pathways and target genes of differentially expressed miRNA were investigated by in silico analysis. METHODS: Nine COF and ten normal bone samples were included in the study. miRNA profiling was carried out by using TaqMan® OpenArray® Human microRNA panel containing 754 validated human miRNAs. We identified the most relevant miRNAs target genes through the leader gene approach, using STRING and Cytoscape software. Pathways enrichment analysis was performed using DIANA-miRPath. RESULTS: Eleven miRNAs were downregulated (hsa-miR-95-3p, hsa-miR-141-3p, hsa-miR-205-5p, hsa-miR-223-3p, hsa-miR-31-5p, hsa-miR-944, hsa-miR-200b-3p, hsa-miR-135b-5p, hsa-miR-31-3p, hsa-miR-223-5p and hsa-miR-200c-3p), and five were upregulated (hsa-miR-181a-5p, hsa-miR-181c-5p, hsa-miR-149-5p, hsa-miR-138-5p and hsa-miR-199a-3p) in COF compared to normal bone. Eighteen common target genes were predicted, and the leader genes approach identified the following genes involved in human COF: EZH2, XIAP, MET and TGFBR1. According to the biology of bone and COF, the most relevant KEGG pathways revealed by enrichment analysis were proteoglycans in cancer, miRNAs in cancer, pathways in cancer, p53-, PI3K-Akt-, FoxO- and TGF-beta signalling pathways, which were previously found to be differentially regulated in bone neoplasms, odontogenic tumours and osteogenesis. CONCLUSION: miRNA dysregulation occurs in COF, and EZH2, XIAP, MET and TGFBR1 are potential targets for functional analysis validation.

Next-generation sequencing of oncogenes and tumor suppressor genes in odontogenic myxomas.

BACKGROUND: Mutations previously considered drivers of malignant neoplasms also occur in benign tumors. From the biological perspective, the study of malignant and benign neoplasms is equally relevant. The study of rare tumors contributes to the understanding of the more common ones, as both could share the same hallmark genetic drivers. The identification of driver mutations in benign tumors is facilitated by the fact that they harbor quiet genomes. Pathogenic mutations have being described in benign epithelial odontogenic tumors, such as ameloblastomas and adenomatoid odontogenic tumors. However, the molecular pathogenesis of odontogenic myxoma (OM), a benign aggressive ectomesenchymal tumor, is still poorly characterized, precluding the development of personalized therapy. Aiming to find druggable genetic mutations, we investigated in OM mutations in 50 genes commonly mutated in cancer. METHODS: We used targeted next-generation sequencing to interrogate over 2,800 COSMIC mutations in OM. RESULTS: Missense single nucleotide variants were detected in KDR, TP53, PIK3CA, KIT, JAK3; however, these did not include pathogenic mutations. CONCLUSION: These aggressive tumors do not harbor pathogenic mutations in genes commonly mutated in human cancers or if they do, these mutations probably occur in a low proportion of cases.

BRAFV600E mutation in the diagnosis of unicystic ameloblastoma.

BACKGROUND: Unicystic ameloblastoma, an odontogenic neoplasm, presents clinical and radiographic similarities with dentigerous and radicular cysts, non-neoplastic lesions. It is not always possible to reach a final diagnosis with the incisional biopsy, leading to inappropriate treatment. The BRAFV600E activating mutation has been reported in a high proportion of ameloblastomas. The purpose of the study was to assess the utility of the detection of the BRAFV600E mutation in the differential diagnosis of unicystic ameloblastoma with dentigerous and radicular cysts. METHODS: Twenty-six archival samples were included, comprising eight unicystic ameloblastomas (UAs), nine dentigerous and nine radicular cysts. The mutation was assessed in all samples by anti-BRAFV600E (clone VE1) immunohistochemistry (IHC) and by TaqMan mutation detection qPCR assay. Sanger sequencing was further carried out when samples showed conflicting results in the IHC and qPCR. RESULTS: Although all UAs (8/8) showed positive uniform BRAFV600E staining along the epithelial lining length, the mutation was not confirmed by qPCR and Sanger sequencing in three samples. Positive staining for the BRAFV600E protein was observed in one dentigerous cyst, but it was not confirmed by the molecular methods. Furthermore, 2/9 dentigerous cysts and 2/9 radicular cysts showed non-specific immunostaining of the epithelium or plasma cells. None of the dentigerous or radicular cysts cases presented the BRAFV600E mutation in the qPCR assay. CONCLUSIONS: The BRAFV600E antibody (clone VE1) IHC may show non-specific staining, but molecular assays may be useful for the diagnosis of unicystic ameloblastoma, in conjunction with clinical, radiological and histopathological features.

Assessment of BRAFV600E and SMOF412E mutations in epithelial odontogenic tumours.

The classification of ameloblastoma in multicystic or unicystic variants is associated with its clinical behaviour. Recently, BRAF and SMO mutations have been reported in ameloblastomas. However, it is not clear if such mutations are shared by the multi- and unicystic variants of ameloblastoma or by odontogenic carcinomas. We assessed BRAFV600E and SMOF412E in multicystic, unicystic and desmoplastic ameloblastomas. In addition, we investigated whether the BRAFV600E mutation occurs in odontogenic carcinomas. A total of 28 formalin-fixed paraffin-embedded samples, comprising 17 ameloblastomas and 11 odontogenic carcinomas, were included. The BRAFV600E mutation was assessed by real-time PCR with a specific TaqMan probe and confirmed by Sanger sequencing. The SMOF412E mutation was assessed by Sanger sequencing. Fourteen out of 17 (82 %) ameloblastomas showed the BRAFV600E mutation, specifically, 5/6 (83 %) unicystic, 7/9 (78 %) multicystic and 2/2 desmoplastic ameloblastomas. BRAFV600E mutation was detected in 4/11 (36 %) malignant tumours, specifically, 3/8 (38 %) ameloblastic carcinomas and 1/1 clear cell odontogenic carcinoma, while the two ghost cell odontogenic carcinomas did not harbour this mutation. The SMOF412E mutation was not detected in ameloblastoma. The BRAFV600E-activating mutation is a common event in ameloblastomas, occurring regardless of site or histological type. This mutation is also detected in odontogenic carcinomas. SMO somatic mutation is a secondary genetic event in the ameloblastoma pathogenesis. Our findings support the possibility for personalised, molecular-targeted therapy for ameloblastomas and odontogenic carcinomas harbouring the BRAFV600E mutation.

An oral clinical approach to Gorlin-Goltz syndrome.

Gorlin-Goltz syndrome is a rare hereditary disease that can have negative effects on one's quality of life. The main clinical features are multiple nevoid basal cell carcinomas, odontogenic keratocysts, congenital skeletal abnormalities, calcification of the falx cerebri, facial dysmorphism, and skin depressions (pits) on the palms and soles. Diagnosis is based on major and minor clinical and radiological criteria and can be confirmed by DNA analysis. This article describes the case of a child with Gorlin-Goltz syndrome and outlines the clinical manifestations of the disease.

Growth rate per year of a soft tissue recurrent ameloblastoma.

Clinical Key Message: We present a case of recurring ameloblastoma in soft tissue, for which we have estimated the growth rate of the lesion. This information could help clinicians to establish follow-up protocols for the early diagnosis of recurrent ameloblastomas. Abstract: In the present paper, we present a case of recurring ameloblastoma in soft tissue, for which we have estimated the growth rate of the lesion. The area of the whole resected specimen was measured using the ImageJ guide for complex object area. After dividing the area of the recurrent tumor by the number of years during the follow-up, we found that the lesion growth rate was 5.3 cm2 per year. Although further studies are still necessary in the literature to assess the growth rate of ameloblastoma, the present report shows a different methodology to estimate it. This information could help clinicians to establish follow-up protocols for the early diagnosis of recurrent ameloblastomas.

Whole-exome sequencing and copy number alterations analysis in a case of expansive florid cemento-osseous dysplasia.

Whole-exome sequencing (WES) analysis of an expansive case florid cemento-osseus dysplasia were reported for the first time. Also, the new potential candidate genes were reported to expand our knowledge about their molecular pathogenesis. Abstract: We report a case of expansive florid cemento-osseus dysplasia in a 32-year-old female patient who presented an expansive tumoral lesion in the anterior mandible. As florid cemento-osseus dysplasia have only been molecularly investigated using targeted-sequencing, fragments of the lesion were collected and subjected to molecular investigation using WES to assess somatic mutations as well as copy number alterations. No gains and losses of chromosomal arms or segments longer than 1 Mb were detected. Our findings revealed a pathogenic stopgain variant at the KIF5C gene, a stoploss variant at MAPK10, and missense SNV at COL6A2 at DCDC1, suggesting potential candidate genes associated with florid cemento-osseus dysplasia.

Tenosynovial giant cell tumor: case report and molecular investigation.

Tenosynovial giant cell tumor is a benign neoplasm arising from the synovium of joints, including the temporomandibular joint (TMJ). Despite its benign nature, these tumors may exhibit aggressive behavior. A 57-year-old woman with a swollen, hardened area in the left TMJ was referred to the university´s clinic. The diagnosis of tenosynovial giant cell tumor was made based on the presence of hyperplastic synovial lining containing mononuclear and giant cells, hemorrhagic areas, hemosiderin deposits, and calcification foci in the biopsy. A low condylectomy was performed, and histopathologic analysis of the surgical piece upheld the diagnosis. Due to histopathologic resemblance with other giant cell-rich lesions (giant cell granuloma of the jaws, brown tumor of hyperparathyroidism, and non-ossifying fibroma) for which signature mutations are known, mutational analysis of KRAS, FGFR1, and TRPV4 genes was conducted. The results revealed wild-type sequences for all the mutations tested, thereby supporting the diagnosis of tenosynovial giant cell tumor.

A new TRPV4 mutation in a case of multiple central giant cell granulomas of the jaws.

Sporadic central giant cell granulomas of the jaws (GCGJ) are often solitary lesions, characterized by KRAS, FGFR1, and TRPV4 somatic mutations. Multifocal lesions may occur and are associated with hyperparathyroidism or underlying syndromes such as cherubism, which is marked by SH3BP2 mutations, and RASopathies, which are caused by mutations in the FGFR-RAS-RAF-MEK-ERK signaling cascade. The diagnosis of multiple GCGJ can be challenging. The present case reports a 14-year-old boy with multiple central GCGJ and no obvious syndromic trait. Sanger sequencing-based analysis revealed wild-type sequences for SH3BP2 (exon 9), KRAS (exons 2-4), and FGFR1 (exons 9 and 10) genes. A rare TRPV4 somatic mutation (p.Val708Met) was detected in the lesion on the right side of the mandible, whereas the other tumor and the normal oral mucosa revealed wild-type TRPV4 sequences. This report expands the spectrum of TRPV4 somatic mutations in central GCGJ.

Cheilitis glandularis: case report and systematic literature review.

Cheilitis glandularis (CG) is a rare inflammatory disease of unknown etiology that affects the minor salivary glands predominantly in the lower lip. In this article, we report the case of an 18-year-old black woman who presented with a deep suppurative type of CG in both lips. In addition, we performed a systematic literature review in five databases (PubMed, Scopus, Web of Science, Ovid, and Embase) to identify CG case reports or case series. A total of 360 references were retrieved in the electronic databases. Thirty-four articles met the inclusion criteria, and six were retrieved through manual search, totaling 40 articles included in the systematic review. Thirty-nine (68.4%) cases occurred in male individuals and 18 (31.6%) in female individuals. The mean age of affected individuals was 40.9 years. Different clinical manifestations ranging from no symptoms to discomfort, pain, swelling, erythema, eversion of the lip, dilated ductal openings, ulcers, and crust have been reported. Among the included CG cases, 41 affected exclusively the lower lip (71.9%). In four cases, the CG only affected the upper lip (7.0%). In 12 cases, the lesion affected both the lower and upper lips (21.1%). Different treatment modalities were adopted in the management of CG. Although the surgical treatment was indicated (42.1%), the conservative treatment with topical medications, as in the present case, resulted in resolution in 21.0% of cases.

Oral follicular lymphoma: a clinicopathologic and molecular study.

Follicular lymphoma is a hematolymphoid neoplasm that originates from germinal center B cells. It is made up of a combination of small cleaved centrocytes and a varying quantity of larger non-cleaved centroblasts to describe the clinical, microscopic, immunohistochemical, and molecular features of oral follicular lymphomas. Follicular lymphomas affecting the oral cavity were retrieved from pathology files. Immunohistochemistry was performed to confirm the diagnosis, and fluorescence in situ hybridization (FISH) was employed to detect rearrangements in BCL2, BCL6, and MYC genes. Clinical and follow-up data were obtained from the patient's medical and pathology files. Twenty cases were obtained. There was an equal sex distribution (10 males: 10 females) and a mean age of 60.9 years (range: 10-83 years-old). Lesions presented as asymptomatic swellings, usually in the palate (10 cases) and the buccal mucosa (7 cases). Five patients presented with concomitant nodal involvement. Microscopic evaluation depicted the follicular growth pattern with diffuse areas in six cases. Grades 1 and 2 follicular lymphomas represented 12 cases, while grade 3A neoplasms accounted for other 8 cases. Two cases showed rearrangements in MYC, BCL2, and BCL6 genes, while single BCL2 translocation was found in eight cases. Two cases had no translocation. Three patients deceased and the 2-year overall survival achieved 88%. Follicular lymphoma affecting the oral cavity is uncommon, usually affects the palate as a non-ulcerated swelling and the presence of a systemic disease most always be ruled out.

Epigenetic regulation of matrix metalloproteinase expression in ameloblastoma.

BACKGROUND: An ameloblastoma is a benign odontogenic neoplasm with aggressive behaviour and high recurrence rates. The increased expression of matrix metalloproteinases (MMPs) has been reported in ameloblastomas. In the present study, we hypothesised that epigenetic alterations may regulate MMP expression in ameloblastomas. METHODS: We investigated the methylation status of the genes MMP-2 and MMP-9 in addition to mRNA transcription and protein expression in ameloblastomas. Methylation analysis was performed by both methylation-specific polymerase chain reaction (MSP-PCR) and restriction enzyme digestion to evaluate the methylation profile of MMP-2 and MMP-9 in 12 ameloblastoma samples and 12 healthy gingiva fragments, which were included as controls. Furthermore, we investigated the transcription levels of the genes by quantitative reverse-transcription PCR (qRT-PCR). Zymography was performed to verify protein expression in ameloblastomas. RESULTS: The ameloblastomas showed a high frequency of unmethylated MMP-2 and MMP-9, whereas the healthy gingival samples presented a sharp prevalence of methylated MMPs. Higher expression levels of MMP-9 were found in ameloblastomas compared to healthy gingiva. However, no significant differences in the MMP-2 mRNA expression between groups was found. All ameloblastomas showed positive expression of MMP-2 and MMP-9 proteins. CONCLUSIONS: Our findings suggest that expression of MMP-9 is increased in ameloblastomas and is possibly modulated by unmethylation of the gene.

Unicystic adenoid ameloblastoma: A new variant?

Adenoid ameloblastoma with dentinoid is an uncommon benign odontogenic neoplasm, and its unicystic variant seems to be even rarer. A 34-year-old man was referred for evaluation of an asymptomatic swelling in the posterior maxilla. Intraoral examination showed an expansive lesion, soft to palpation, covered by a normal color mucosa. Cone beam computed tomography revealed a well-defined unilocular hypodense tumor involving the left maxillary sinus. Histopathological examination of the surgically excised specimen showed a cystic tumor lined by an ameloblastic-like epithelium containing columnar basal cells with hyperchromatic and polarized nuclei. In some areas of the capsule, the tumor showed mural infiltration by sheets of cells containing central whirling structures. Dentinoid material was also observed in association with ameloblastic-like cells. The tumor was BRAF and KRAS wild-type. Collectively, these findings were consistent with the diagnosis of a unicystic variant of adenoid ameloblastoma with dentinoid.