Primary mucosal melanomas of the head and neck are characterised by overexpression of the DNA mutating enzyme APOBEC3B.

AIMS: Primary head/neck mucosal melanomas (MMs) are rare and exhibit aggressive biologic behaviour and elevated mutational loads. The molecular mechanisms responsible for high genomic instability observed in head/neck MMs remain elusive. The DNA cytosine deaminase APOBEC3B (A3B) constitutes a major endogenous source of mutation in human cancer. A3B-related mutations are identified through C-to-T/-G base substitutions in 5'-TCA/T motifs. Herein, we present immunohistochemical and genomic data supportive of a role for A3B in head/neck MMs. METHODS AND RESULTS: A3B protein levels were assessed in oral (n = 13) and sinonasal (n = 13) melanomas, and oral melanocytic nevi (n = 13) by immunohistochemistry using a custom rabbit α-A3B mAb (5210-87-13). Heterogeneous, selective-to-diffuse, nuclear only, A3B immunopositivity was observed in 12 of 13 (92.3%) oral melanomas (H-score range = 9-72, median = 40) and 8 of 13 (62%) sinonasal melanomas (H-score range = 1-110, median = 24). Two cases negative for A3B showed prominent cytoplasmic staining consistent with A3G. A3B protein levels were significantly higher in oral and sinonasal MMs than intraoral melanocytic nevi (P < 0.0001 and P = 0.0022, respectively), which were A3B-negative (H-score range = 1-8, median = 4). A3B levels, however, did not differ significantly between oral and sinonasal tumours (P > 0.99). NGS performed in 10 sinonasal MMs revealed missense NRAS mutations in 50% of the studied cases and one each KIT and HRAS mutations. Publicly available whole-genome sequencing (WGS) data disclosed that the number of C-to-T mutations and APOBEC3 enrichment score were markedly elevated in head/neck MMs (n = 2). CONCLUSION: The above data strongly indicate a possible role for the mutagenic enzyme A3B in head/neck melanomagenesis, but not benign melanocytic neoplasms.

Endogenous APOBEC3B overexpression characterizes HPV-positive and HPV-negative oral epithelial dysplasias and head and neck cancers.

The DNA cytosine deaminase APOBEC3B (A3B) is a newly recognized endogenous source of mutations in a range of human tumors, including head/neck cancer. A3B inflicts C-to-T and C-to-G base substitutions in 5'-TCA/T trinucleotide motifs, contributes to accelerated rates of tumor development, and affects clinical outcomes in a variety of cancer types. High-risk human papillomavirus (HPV) infection causes A3B overexpression, and HPV-positive cervical and head/neck cancers are among tumor types with the highest degree of APOBEC signature mutations. A3B overexpression in HPV-positive tumor types is caused by the viral E6/E7 oncoproteins and may be an early off-to-on switch in tumorigenesis. In comparison, less is known about the molecular mechanisms responsible for A3B overexpression in HPV-negative head/neck cancers. Here, we utilize an immunohistochemical approach to determine whether A3B is turned from off-to-on or if it undergoes a more gradual transition to overexpression in HPV-negative head/neck cancers. As positive controls, almost all HPV-positive oral epithelial dysplasias and oropharyngeal cancers showed high levels of nuclear A3B staining regardless of diagnosis. As negative controls, A3B levels were low in phenotypically normal epithelium adjacent to cancer and oral epithelial hyperplasias. Interestingly, HPV-negative and low-grade oral epithelial dysplasias showed intermediate A3B levels, while high-grade oral dysplasias showed high A3B levels similar to oral squamous cell carcinomas. A3B levels were highest in grade 2 and grade 3 oral squamous cell carcinomas. In addition, a strong positive association was found between nuclear A3B and Ki67 scores suggesting a linkage to the cell cycle. Overall, these results support a model in which gradual activation of A3B expression occurs during HPV-negative tumor development and suggest that A3B overexpression may provide a marker for advanced grade oral dysplasia and cancer.

Identification of a Sjögren's syndrome susceptibility locus at OAS1 that influences isoform switching, protein expression, and responsiveness to type I interferons.

Sjögren's syndrome (SS) is a common, autoimmune exocrinopathy distinguished by keratoconjunctivitis sicca and xerostomia. Patients frequently develop serious complications including lymphoma, pulmonary dysfunction, neuropathy, vasculitis, and debilitating fatigue. Dysregulation of type I interferon (IFN) pathway is a prominent feature of SS and is correlated with increased autoantibody titers and disease severity. To identify genetic determinants of IFN pathway dysregulation in SS, we performed cis-expression quantitative trait locus (eQTL) analyses focusing on differentially expressed type I IFN-inducible transcripts identified through a transcriptome profiling study. Multiple cis-eQTLs were associated with transcript levels of 2'-5'-oligoadenylate synthetase 1 (OAS1) peaking at rs10774671 (PeQTL = 6.05 × 10-14). Association of rs10774671 with SS susceptibility was identified and confirmed through meta-analysis of two independent cohorts (Pmeta = 2.59 × 10-9; odds ratio = 0.75; 95% confidence interval = 0.66-0.86). The risk allele of rs10774671 shifts splicing of OAS1 from production of the p46 isoform to multiple alternative transcripts, including p42, p48, and p44. We found that the isoforms were differentially expressed within each genotype in controls and patients with and without autoantibodies. Furthermore, our results showed that the three alternatively spliced isoforms lacked translational response to type I IFN stimulation. The p48 and p44 isoforms also had impaired protein expression governed by the 3' end of the transcripts. The SS risk allele of rs10774671 has been shown by others to be associated with reduced OAS1 enzymatic activity and ability to clear viral infections, as well as reduced responsiveness to IFN treatment. Our results establish OAS1 as a risk locus for SS and support a potential role for defective viral clearance due to altered IFN response as a genetic pathophysiological basis of this complex autoimmune disease.

Regulation of Osteoclast Differentiation at Multiple Stages by Protein Kinase D Family Kinases.

Balanced osteoclast and osteoblast activity is necessary for skeletal health, whereas unbalanced osteoclast activity causes bone loss in many skeletal conditions. A better understanding of pathways that regulate osteoclast differentiation and activity is necessary for the development of new therapies to better manage bone resorption. The roles of Protein Kinase D (PKD) family of serine/threonine kinases in osteoclasts have not been well characterized. In this study we use immunofluorescence analysis to reveal that PKD2 and PKD3, the isoforms expressed in osteoclasts, are found in the nucleus and cytoplasm, the mitotic spindle and midbody, and in association with the actin belt. We show that PKD inhibitors CRT0066101 and CID755673 inhibit several distinct aspects of osteoclast formation. Treating bone marrow macrophages with lower doses of the PKD inhibitors had little effect on M-CSF + RANKL-dependent induction into committed osteoclast precursors, but inhibited their motility and subsequent differentiation into multinucleated mature osteoclasts, whereas higher doses of the PKD inhibitors induced apoptosis of the preosteoclasts. Treating post-fusion multinucleated osteoclasts with the inhibitors disrupted the osteoclast actin belts and impaired their resorptive activity. In conclusion, these data implicate PKD kinases as positive regulators of osteoclasts, which are essential for multiple distinct processes throughout their formation and function.

Intraoral Cutaneous Hamartomas-Clinicopathologic and Immunohistochemical Characteristics of 3 Cases.

Intraoral cutaneous hamartomas (ICHs) are uncommon mucosal lesions characterized microscopically by a combination of cutaneous structures, including various stages of follicular and sebaceous elements. Due to their rarity, the clinicopathologic and immunohistochemical attributes of ICHs have not been thoroughly delineated. Three cases of ICH were identified from our records, and formalin-fixed paraffin-embedded sections were immunohistochemically stained with antibodies against androgen receptor, estrogen receptor, and progesterone receptor, p63, factor XIIIα, and CD34. All 3 ICHs involved the buccal mucosa with an M:F ratio = 2:1 and mean age = 42.3 years (age range: 27-61 years). ICHs presented as thickened, painless, white and yellow plaques or nodules of long duration, measuring 0.6-1.5 cm. No history of skin graft in the area of the lesions was reported. Histopathologically, the lesions showed aggregates of rudimentary folliculosebaceous structures. Although well-defined piloerector muscles were present in all cases of ICH, bona fide hair follicles and isolated hair shafts were identified only in 1 case. The overlying oral epithelium exhibited epidermis-like morphological features, while inflammation was generally absent. Immunohistochemically, strong and diffuse nuclear staining for androgen receptor and factor XIIIα was observed in the sebaceous glands, and estrogen receptor and p63 reactivity were confined exclusively to the peripheral basal cells, while progesterone receptor staining was negative in ICHs. CD34 diffusely decorated the lesional stroma. In conclusion, ICH is a rare lesion composed of cutaneous elements in an abnormal location. A predilection for the buccal mucosa is reported in the current study.

Serum Markers of Bone Turnover and Angiogenesis in Patients With Bisphosphonate-Related Osteonecrosis of the Jaw After Discontinuation of Long-Term Intravenous Bisphosphonate Therapy.

PURPOSE: To analyze serum markers of bone turnover, angiogenesis, endocrine function, and inflammation in patients with bisphosphonate-related osteonecrosis of the jaw (BRONJ) who discontinued long-term intravenous bisphosphonate (BP) therapy. PATIENTS AND METHODS: Serum samples were obtained from 25 BRONJ patients who had discontinued long-term intravenous BP therapy for an average of 11.4 ± 8.7 months and 48 non-BRONJ controls who continued receiving intravenous BP therapy. Samples were analyzed for total alkaline phosphatase, bone-specific alkaline phosphatase, osteocalcin, C-telopeptide, vascular endothelial growth factor, triiodothyronine, thyroxine, thyroid-stimulating hormone, 25-hydroxyvitamin D, and C-reactive protein. RESULTS: The mean number of BP infusions was significantly higher in BRONJ patients compared with controls (38.4 ± 26.3 infusions vs 18.8 ± 7.2 infusions, P < .0001); however, the duration of BP therapy was not significantly different between the groups (P = .23). Overall, there were no significant differences in any of the markers between BRONJ patients and controls (all P values ≥ .16). In a subgroup analysis that matched BRONJ patients and controls according to mean age and number of BP infusions (10 BRONJ patients and 48 controls), log10 vascular endothelial growth factor (2.9 ± 0.4 pg/mL vs 2.4 ± 0.4 pg/mL, P < .001) and C-reactive protein (34 ± 26 mg/L vs 13 ± 8 mg/L, P < .01) levels were significantly higher in BRONJ patients compared with controls. Within BRONJ patients, none of the serum markers were correlated with duration of BP discontinuation. CONCLUSIONS: Levels of bone turnover and endocrine markers in BRONJ patients who discontinue long-term intravenous BP therapy are similar to those in non-BRONJ controls receiving intravenous BP therapy. However, levels of angiogenesis and inflammation markers are higher in BRONJ patients who discontinue long-term intravenous BP therapy. The prolonged skeletal half-life of BPs may suppress bone turnover markers in BRONJ patients for several years after discontinuation of intravenous BP therapy, suggesting an extended effect on bone homeostasis.

The Function of Twisted Gastrulation in Regulating Osteoclast Differentiation is Dependent on BMP Binding.

Proper regulation of osteoclast (OCL) function is critical for normal bone homeostasis. Bone morphogenetic protein (BMP) signaling and its regulation have been shown to have direct effects on OCL differentiation and activity. One of the major modulators of BMP signaling in the extracellular space is the secreted protein twisted gastrulation (TWSG1), which can inhibit BMP signaling and OCL differentiation. In this study we examine specific N-terminal regions of TWSG1 protein that have been previously proposed as BMP binding sites to determine whether TWSG1 binding to BMPs is required for its inhibitory effects on OCLs. We demonstrate that overexpression of wild type TWSG1 suppresses osteoclastogenesis, while overexpression of mutant TWSG1 proteins (W66A and N80Q/N146Q mutants), which cannot bind BMPs, leads to increased BMP signaling, enhanced osteoclastogenesis, increased resorptive activity, and expression of OCL-specific genes. Our results show that BMP binding is required for TWSG1-mediated inhibition of OCL formation and function, and validate the critical functional regions within the TWSG1 protein for these interactions.

BMP-binding protein twisted gastrulation is required in mammary gland epithelium for normal ductal elongation and myoepithelial compartmentalization.

Bone morphogenetic proteins (BMPs) are involved in embryonic mammary gland (MG) development and can be dysregulated in breast cancer. However, the role BMPs play in the postnatal MG remains virtually unknown. BMPs are potent morphogens that are involved in cell fate determination, proliferation, apoptosis and adult tissue homeostasis. Twisted gastrulation (TWSG1) is a secreted BMP binding protein that modulates BMP ligand availability in the extracellular space. Here we investigate the consequences of TWSG1 deletion on development of the postnatal MG. At puberty, Twsg1 is expressed in the myoepithelium and in a subset of body cells of the terminal end buds. In the mature duct, Twsg1 expression is primarily restricted to the myoepithelial layer. Global deletion of Twsg1 leads to a delay in ductal elongation, reduced secondary branching, enlarged terminal end buds, and occluded lumens. This is associated with an increase in luminal epithelial cell number and a decrease in apoptosis. In the MG, pSMAD1/5/8 level and the expression of BMP target genes are reduced, consistent with a decrease in BMP signaling. GATA-3, which is required for luminal identity, is reduced in Twsg1(-/-) MGs, which may explain why K14 positive cells, which are normally restricted to the myoepithelial layer, are found within the luminal compartment and shed into the lumen. In summary, regulation of BMP signaling by TWSG1 is required for normal ductal elongation, branching of the ductal tree, lumen formation, and myoepithelial compartmentalization in the postnatal MG.

Protein kinase D promotes in vitro osteoclast differentiation and fusion.

Although PKD is broadly expressed and involved in numerous cellular processes, its function in osteoclasts has not been previously reported. In this study, we found that PKD2 is the main PKD isoform expressed in osteoclastic cells. PKD phosphorylation, indicative of the activated state, increased after 2-3 days of treatment of bone marrow macrophages with M-CSF and RANKL, corresponding to the onset of preosteoclast fusion. RNAi against PKD2 and treatment with the PKD inhibitor CID755673 showed that PKD activity is dispensable for induction of bone marrow macrophages into tartrate-resistant acid phosphatase-positive preosteoclasts in culture but is required for the transition from mononucleated preosteoclasts to multinucleated osteoclasts. Loss of PKD activity reduced expression of DC-STAMP in RANKL-stimulated cultures. Overexpression of DC-STAMP was sufficient to rescue treatment with CID755673 and restore fusion into multinucleated osteoclasts. From these data, we conclude that PKD activity promotes differentiation of osteoclast progenitors through increased expression of DC-STAMP.

Comparison of the American-European Consensus Group Sjogren's syndrome classification criteria to newly proposed American College of Rheumatology criteria in a large, carefully characterised sicca cohort.

OBJECTIVE: To compare the performance of the American-European Consensus Group (AECG) and the newly proposed American College of Rheumatology (ACR) classification criteria for Sjögren's Syndrome (SS) in a well-characterised sicca cohort, given ongoing efforts to resolve discrepancies and weaknesses in the systems. METHODS: In a multidisciplinary clinic for the evaluation of sicca, we assessed features of salivary and lacrimal gland dysfunction and autoimmunity as defined by tests of both AECG and ACR criteria in 646 participants. Global gene expression profiles were compared in a subset of 180 participants. RESULTS: Application of the AECG and ACR criteria resulted in classification of 279 and 268 participants with SS, respectively. Both criteria were met by 244 participants (81%). In 26 of the 35 AECG+/ACR participants, the minor salivary gland biopsy focal score was ≥1 (74%), while nine had positive anti-Ro/La (26%). There were 24 AECG-/ACR+ who met ACR criteria mainly due to differences in the scoring of corneal staining. All patients with SS, regardless of classification, had similar gene expression profiles, which were distinct from the healthy controls. CONCLUSIONS: The two sets of classification criteria yield concordant results in the majority of cases and gene expression profiling suggests that patients meeting either set of criteria are more similar to other SS participants than to healthy controls. Thus, there is no clear evidence for increased value of the new ACR criteria over the old AECG criteria from the clinical or biological perspective. It is our contention, supported by this report, that improvements in diagnostic acumen will require a more fundamental understanding of the pathogenic mechanisms than is at present available.

Maternal diet supplementation with methyl donors and increased parity affect the incidence of craniofacial defects in the offspring of twisted gastrulation mutant mice.

Diets rich in methyl-donating compounds, including folate, can provide protection against neural tube defects, but their role in preventing craniofacial defects is less clear. Mice deficient in Twisted gastrulation (TWSG1), an extracellular modulator of bone morphogenetic protein signaling, manifest both midline facial defects and jaw defects, allowing study of the effects of methyl donors on various craniofacial defects in an experimentally tractable animal model. The goal of this study was to examine the effects of maternal dietary supplementation with methyl donors on the incidence and type of craniofacial defects among Twsg1(-/-) offspring. Nulliparous and primiparous female mice were fed an NIH31 standard diet (control) or a methyl donor supplemented (MDS) diet (folate, vitamin B-12, betaine, and choline). Observed defects in the pups were divided into those derived mostly from the first branchial arch (BA1) (micrognathia, agnathia, cleft palate) and midline facial defects in the holoprosencephaly spectrum (cyclopia, proboscis, and anterior truncation). In the first pregnancy, offspring of mice fed the MDS diet had lower incidence of BA1-derived defects (12.8% in MDS vs. 32.5% in control; P = 0.02) but similar incidence of midline facial defects (6.4% in MDS vs. 5.2% in control; P = 1.0). Increased maternal parity was independently associated with increased incidence of craniofacial defects after adjusting for diet (from 37.7 to 59.5% in control, P = 0.04 and from 19.1 to 45.3% in MDS, P = 0.045). In conclusion, methyl donor supplementation shows protective effects against jaw defects, but not midline facial defects, and increased parity can be a risk factor for some craniofacial defects.

Teriparatide therapy for bisphosphonate-related osteonecrosis of the jaw: a case report and narrative review.

Bisphosphonates (BP), potent antresorptive agents, play a key role in managing osteolytic bone disorders including osteoporosis, Paget's disease, bone metastasis, and multiple myeloma. However, their long-term administration is associated with increased risk for bisphosphonate-related osteonecrosis of the jaw (BRONJ) development. At present, there is no curative therapy for BRONJ, and patients are often treated palliatively with antibiotics, antimicrobial mouth rinses, and debridement of necrotic bone. This article highlights a new treatment modality that may be beneficial to a subset of osteoporosis patients suffering from BRONJ. Here we report a BRONJ case that was initially unresponsive to conservative treatment, but subsequently responded to teriparatide (recombinant human PTH1-34) therapy.

An Unusual Gingival (Peripheral) Tumor with Features of Keratoameloblastoma with Cytologic Atypia or Possible Malignant Transformation Exhibiting ARID1A Mutation.

BACKGROUND: Keratoameloblastoma is a poorly characterized and rarely reported odontogenic neoplasm that can exhibit overlapping histopathologic features with conventional ameloblastoma and keratocystic odontogenic tumor (KCOT), with an ambiguous relationship to the so-called solid KCOT. METHODS: A peripheral maxillary tumor causing bone saucerization in a 54-year-old male is described and investigated with immunohistochemistry and Next-Generation Sequencing (NGS). RESULTS: Microscopically, the tumor comprised of a predominantly plexiform proliferation of odontogenic epithelium with central keratinization and evidence of surface origin. Peripheral cells exhibited nuclear palisading with variable reverse polarization, while stellate reticulum-like areas were observed internally. A few follicles and a few foci in the lining of cystic spaces revealed increased cellularity with cells exhibiting small but conspicuous nucleoli, focal nuclear hyperchromatism, and a few mitoses mostly seen in the peripheral outer cell layer. Nuclear staining for ki-67 was increased in those areas when compared with the other cystic, follicular, and plexiform areas. These features were interpreted as cytologic atypia suggesting also the possibility of a malignant process. Immunohistochemically, the tumor was positive for CK19 and negative for BRAF VE1, calretinin, and CD56. Ber-Ep4 was only focally positive. By sequencing, an ARID1A c.6527_6538delAG frameshift mutation (VAF: 5.8%), classified as likely oncogenic, and an FBXW7 c.1627 A > G missense mutation (VAF: 8.0%), classified as a variant of uncertain significance, were detected. Two mutations, probably germline (VAF ~ 50%), were recorded for RNF43 and FBXW7. No pathogenic variants were identified in PTCH1, BRAF, NRAS, HRAS, KRAS, FGFR2, or SMO genes. CONCLUSION: The significance of an ARID1A variant in keratoameloblastoma is uncertain since this variant has not been reported in ameloblastoma or KCOT, to date. Alternatively, it may characterize malignant transformation in the present case since ARID1A mutations have been encountered in various cancers. Sequencing of additional cases is necessary to determine whether this may represent a recurrent genomic event.

Intraoral salivary lymphoepithelial carcinoma: clinicopathologic and immunophenotypic characterization of 3 cases indicates elevated programmed death-ligand 1 expression.

OBJECTIVE: Intraoral salivary lymphoepithelial carcinoma (ISLEC) is a rare malignancy with programmed death-ligand 1 (PD-L1) expression levels that have been greatly understudied. We examined the clinicopathologic and immunophenotypic characteristics, including PD-L1 levels, of 3 cases of ISLEC. STUDY DESIGN: We searched the archives of 2 oral and maxillofacial pathology laboratories for specimens diagnosed as ISLEC between 1985 and 2022. We collected patient demographic and clinical data. Immunostaining for AE1/AE3, CK7, CD3, CD20, p16, p53, Ki67, and PD-L1 (SP263), as well as Epstein-Barr virus-encoded small RNAs (EBER) in situ hybridization (ISH) were performed. RESULTS: All 3 cases affected males aged 42 to 84 years (median = 61y) and involved the floor of the mouth, soft palate/uvula, and tongue. The lesions showed diffuse infiltration by non-keratinizing sheets and islands of undifferentiated carcinoma cells with associated dense lymphoplasmacytic inflammation. Immunohistochemically, all tumors showed AE1/AE3 positivity, selective p53 staining, and negativity for CK7 and p16. Ki67 highlighted 20%-80% of lesional cells. The inflammatory infiltrate comprised a mixed population of T and B lymphocytes. EBER ISH was positive in one case. All ISLECs displayed membranous, focal-to-diffuse, PD-L1 staining with tumor proportion score > 95% in two and 40-50% in the third case. CONCLUSIONS: The clinicopathologic and immunophenotypic characteristics of the cases we examined highlight the rarity of ISLEC and indicate overall high PD-L1 levels in this type of malignancy, rendering patients with ISLEC potential candidates for targeted α-PD-1/PD-L1 immunotherapy.

The molecular and cellular basis of variable craniofacial phenotypes and their genetic rescue in Twisted gastrulation mutant mice.

The severity of numerous developmental abnormalities can vary widely despite shared genetic causes. Mice deficient in Twisted gastrulation (Twsg1(-/-)) display such phenotypic variation, developing a wide range of craniofacial malformations on an isogenic C57BL/6 strain background. To examine the molecular basis for this reduced penetrance and variable expressivity, we used exon microarrays to analyze gene expression in mandibular arches from several distinct, morphologically defined classes of Twsg1(-/-) and wild type (WT) embryos. Hierarchical clustering analysis of transcript levels identified numerous differentially expressed genes, clearly distinguishing severely affected and unaffected Twsg1(-/-) mutants from WT embryos. Several genes that play well-known roles in craniofacial development were upregulated in unaffected Twsg1(-/-) mutant embryos, suggesting that they may compensate for the loss of TWSG1. Imprinted genes were overrepresented among genes that were differentially expressed particularly between affected and unaffected mutants. The most severely affected embryos demonstrated increased p53 signaling and increased expression of its target, Trp53inp1. The frequency of craniofacial defects significantly decreased with a reduction of p53 gene dosage from 44% in Twsg1(-/-)p53(+/+) pups (N=675) to 30% in Twsg1(-/-)p53(+/-) (N=47, p=0.04) and 15% in Twsg1(-/-)p53(-/-) littermates (N=39, p=0.001). In summary, these results demonstrate that phenotypic variability in Twsg1(-/-) mice is associated with differential expression of certain developmentally regulated genes, and that craniofacial defects can be partially rescued by reduced p53 levels. We postulate that variable responses to stress may contribute to variable craniofacial phenotypes by triggering differential expression of genes and variable cellular apoptosis.

Metastatic Tumors to the Oral Soft Tissues and Jawbones: A Retrospective Analysis of 40 Cases and Review of the Literature.

BACKGROUND: Metastasis to the oral soft tissues and jawbones is rare and frequently associated with wide spread disease and dismal prognosis. Herein, we report the clinicopathologic characteristics of 40 intraoral metastatic neoplasms and perform a comprehensive review of the pertinent literature. METHODS: Criteria for inclusion included: (a) archived cases from the UMN Oral Pathology laboratory with available tissue blocks and/or H&E-stained preparations diagnosed between 2003 and 2021, (b) proper documentation of the clinico-radiographic characteristics of oral metastasis along with confirmed history of primary malignancy, or (c) microscopic findings consistent with metastatic disease with or without discovery of the primary site. RESULTS: Intraoral metastases comprised 0.03% of all accessioned cases; 22 (55%) occurred in men and 18 (45%) in women (median age = 66.5; range = 18-94 years). Eighteen cases (45%) involved the gingiva, 16 (40%) the gingiva and jawbones, 5 (12.5%) were exclusively intraosseous, and 1 affected (2.5%) the tongue. The lung was the two most frequent primary site in both men (n = 6, 27.3%) and women (n = 5, 27.7%), followed by the colon (n = 4, 18.2%) and kidney (n = 3, 13.7%) in men, and colon (n = 4, 22.2%) and breast (n = 3, 16.6%) in women. Analysis of 1,084 metastatic cases from the literature (male-to-female ratio = 1.2; mean = 52.3; range = 0.6-90 years) indicated strong preference for the jawbones (69.5%) and significant site-specific predilection of certain primary malignancies. CONCLUSIONS: Oral and gnathic metastases are rare but demonstrate a clear predilection for the gingiva and mandible. Clinicians should remain cognizant of such lesions since they frequently mimic inflammatory, reactive or benign neoplastic processes and, in certain cases, are the first indication of occult disease.

Whole Exome Sequencing Identifies Somatic Variants in an Oral Composite Hemangioendothelioma Characterized by YAP1-MAML2 Fusion.

Composite hemangioendothelioma (CHE) is considered a borderline malignant vascular tumor defined by an admixture of distinct vascular neoplastic components. A 21-year-old female is presented herein with a 1 cm painless mandibular vestibular mass of less than a year duration. The infiltrating tumor was characterized by dilated vascular channels lined by endothelial cells with bland ovoid or round nuclei exhibiting, occasionally, hobnail/matchstick-like arrangement. Intravascular cell proliferations with hyaline globular deposits were also present. Additionally, lobular spindle and epithelioid cell aggregates, as well as slit-like spaces exhibiting a retiform or angiosarcomatous morphology were observed. Intracytoplasmic signet-ring or lipoblast-like vacuolization was also noted. Mitotic activity was exceptionally rare. Vascular spaces and the stroma featured lymphocytes and plasma cells. Neoplastic cells were positive for CD31, CD34, D2-40 and ERG, negative for CAMTA1 and synaptophysin, while type IV collagen highlighted the plasmalemma of most vessels and hyaline globules. Fluorescence in situ hybridization revealed gene rearrangements in both YAP1 and MAML2 genes, in keeping with a YAP1-MAML2 fusion. Whole exome sequencing (WES) identified three missense mutations FLT1 [p.R1016G], PIK3CA [p.H1047L], and C11orf42 [p.A304P] and a mitochondrial frameshift insertion MT-ND4 [c.1107_1108insC; p.P370fs]. These WES results suggest that FLT1 and/or PIK3CA variants may contribute to tumor growth/transformation while the MT-ND4 variant may relate to proliferation, angiogenesis and/or inhibition of apoptosis.

Bone morphogenetic protein 2 signaling in osteoclasts is negatively regulated by the BMP antagonist, twisted gastrulation.

Bone morphogenetic proteins (BMPs) have been shown to regulate both osteoblasts and osteoclasts. We previously reported that BMP2 could directly enhance RANKL-mediated osteoclast differentiation by increasing the size and number of osteoclasts. Similarly, genetic deletion of the BMP antagonist Twisted gastrulation (TWSG1) in mice, resulted in an enhancement of osteoclast formation, activity and osteopenia. This was accompanied by increased levels of phosphorylated Smad (pSmad) 1/5/8 in Twsg1(-/-) osteoclasts in vitro. The purpose of this study was to develop an adenoviral vector overexpressing Twsg1 as a means of inhibiting osteoclast activity. We demonstrate that overexpressing TWSG1 in primary osteoclasts decreased the size and number of multinuclear TRAP-positive osteoclasts, expression of osteoclast genes, and resorption ability. Overexpression of TWSG1 did not affect osteoclast proliferation or apoptosis. However, overexpression of TWSG1 decreased the levels of pSmad 1/5/8 in osteoclasts. Addition of exogenous BMP2 to osteoclasts overexpressing TWSG1 rescued the size and levels of pSmad 1/5/8 compared to cultures infected with a control virus. Finally, TWSG1 overexpression in osteoclasts isolated from the Twsg1(-/-) mice rescued size of the osteoclasts while further addition of exogenous BMP2 reversed the effect of TWSG1 overexpression and increased the size of the osteoclasts similar to control virus infected cells. Taken together, we demonstrate that overexpressing TWSG1 in osteoclasts via an adenoviral vector results in inhibition of osteoclastogenesis and may provide a potential therapy for inhibiting osteoclast activity in a localized manner.

Matrix metalloproteinase-9 expression in alveolar extraction sockets of Zoledronic acid-treated rats.

PURPOSE: The use of nitrogen-containing bisphosphonates (n-bis) is associated with necrosis of the jaws, also known as bisphosphonate-related osteonecrosis of the jaws (BRONJ); however, the pathophysiology is unknown. Matrix metalloproteinase-9 (MMP-9) expression is essential for normal bone healing and is also required for angiogenesis. N-bis alters MMP-9 expression in vitro and in vivo; therefore, we hypothesized that n-bis alters MMP-9 expression during oral wound healing after tooth extraction. MATERIALS AND METHODS: A total accumulated dose of 2.25 mg/kg (n = 20) of Zoledronic acid (ZA) Zometa or saline (control, n = 20) was administered to Sprague-Dawley male rats. Next, both groups had maxillary molar teeth extracted. Rats were sacrificed at postoperative day 1, 3, 7, or 21. Western blotting or multiplex ELISA was used to evaluate proteins of interest. Real-time polymerase chain reaction was used to assess the relative quantities of target gene mRNA. MMP-9 enzymatic activity was assessed by zymography. RESULTS: The ZA group showed a statistically significant reduction in bone mineralization rate 21 days after tooth extraction compared with the control group (Student t test, P = .005). Moreover, ZA-treated animals showed a statistically significant increase in MMP-9-specific mRNA at postoperative days 3 (P = .003), 7 (P < .0001), and 21 (P < .0001) and protein on postoperative days 3 (P = .005) and 7 (P < .0001). MMP-9 enzymatic activity was also increased in ZA-treated rats compared with control animals (Student t test, P = .014). We also evaluated the extraction sockets for the presence of tissue inhibitor of MMP-1 (TIMP1), which is an inhibitor of MMP-9 enzymatic activity. TIMP1-specific mRNA and protein were not significantly altered by ZA treatment at the times tested (P > .05). Receptor of NF-κB ligand (RANKL) is known to regulate the expression of MMP-9; we therefore assessed the RANKL expression in our experimental oral wound-healing model. The ZA-treated animals had significantly increased RANKL mRNA at postoperative days 3 (P = .02) and 21 (P = .004), while the protein expression was significantly increased at postoperative days 1 (P < .0001), 7 (P = .02), and 21 (P = .03) compared with the control group. CONCLUSIONS: ZA reduced bone mineralization within tooth extraction sockets, suggesting aberrant bone healing. ZA increases the amount and enzymatic activity of MMP-9, while apparently not altering the amount of TIMP1 within extraction sockets. RANKL is increased in ZA-treated rats, which suggests that increased MMP-9 expression is due, in part, to augmented RANKL expression.

Self-regressing oral CD30-positive, EBV-negative, T-cell lymphoproliferative lesions. A poorly understood process highlighted by ominous clinicopathologic features and indolent behavior.

OBJECTIVE: Intraoral, primary, CD30-positive (CD30+) T-cell lymphoproliferative disorders (TLPDs) are uncommon, and their clinicopathologic presentation and management can vary and may be challenging. Herein, we present a retrospective study of 4 examples of self-regressing primary CD30+ TLPD affecting the gingiva. STUDY DESIGN: Archived files were retrospectively reviewed for oral CD30+ TLPDs featuring (1) proper immunohistochemical documentation, (2) Epstein-Barr virus negativity, (3) adequate follow-up information corroborating regression, and (4) no history of hematopoietic malignancy or related-mucocutaneous disease. RESULTS: Three women and 1 man (age range, 55-82 years; mean, 68.3 years) presented with rapidly growing gingival ulcers. Microscopic evaluation revealed diffuse infiltration by sheets of large, atypical cells admixed with lymphocytes and eosinophils, showing angiocentric distribution, focal neurotropism, and muscle infiltration. The lesional cells consistently stained for CD3 and CD30 and were variably immunoreactive against CD2, CD4, CD5, CD7, and CD8, but were negative for ALK1 and EBV-encoded small RNA. TCR-γ gene rearrangement studies revealed a monoclonal T-cell population in 1 case. All lesions showed complete regression 2 to 8 weeks postoperatively (mean follow-up, 4.5 weeks). CONCLUSIONS: Notwithstanding their alarming clinicopathologic appearance, there are CD30+ TLPDs confined to the oral cavity that have an indolent course. However, clinical staging is essential to exclude aggressive systemic malignancy.