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Studies have shown increased numbers of myofibroblasts (MFs) in the stroma of odontogenic lesions with locally aggressive biological behavior. Keratinocytes in odontogenic lesions have been shown to release transforming growth factor (TGF)-β1, which activates the transdifferentiation of fibroblasts to MFs. In turn, MFs secrete matrix metalloproteinase (MMP)-2, potentiating active, rather than passive, lesional growth through bone resorption. To assess the expression of MFs, TGF-β1, and MMP-2 using immunohistochemistry in odontogenic cysts and tumors and to correlate the findings with the biological behavior of the lesions. Formalin-fixed paraffin-embedded tissue samples of locally aggressive (odontogenic keratocysts [OKC], n = 11; ameloblastoma [AM], n = 11) and nonaggressive (radicular cysts [RC], n = 12; dentigerous cysts [DC], n = 10) odontogenic cysts and tumors were stained with antibodies against α-SMA, h-Caldesmon, TGF-β1, and MMP-2. Qualitative and quantitative analyses of positively stained cells were undertaken and compared between the groups. Analysis of MFs was achieved with the inclusion of anti-h-Caldesmon. The expression of MFs and MMP-2 was significantly higher in the locally aggressive group (OKC and AM) in comparison with the nonaggressive group (RC and DC; P <.0001). Interestingly, this was opposite for the cytokine TGF-β1, in which an increased expression was observed in RC and DC compared with the aggressive group (P <.05). The high expression of MFs and MMP-2 positive cells in aggressive odontogenic lesions (OKC and AM) suggests that these cells may be responsible for the biological behavior of these lesions. [ABSTRACT FROM AUTHOR]

Oral squamous cell carcinoma (OSCC) is an aggressive, highly immunosuppressive cancer with a high mortality rate. Interactions between programmed cell death protein 1 (PD-1; on T cells) and programmed death ligand 1 (PD-L1; on tumor cells) within the tumor microenvironment facilitates T-lymphocyte exhaustion. Regulatory T cells (Treg) are a distinct lymphocyte population, expressing the transcription factor forkhead homeobox protein-3 (FoxP3), which downregulates immune responses in OSCC. PD-L1+ tumor cells and FoxP3+ Treg expression in OSCC has been associated with poor prognosis. This research investigates the expression of PD-L1+ cells and Tregs in control, dysplastic, and OSCC tissues. To investigate and compare the expression of PD-L1+ tumor cells and FoxP3+ Tregs in nondysplastic tisssue, dysplastic tissue, and OSCC using immunohistochemistry. Immunohistochemistry was performed on formalin-fixed, paraffin-embedded, archival tissues. Qualitative and quantitative analyses of positively stained cells were undertaken and the dysplastic (n = 20) and OSCC groups (n = 20) were compared against the non-dysplastic control group (n = 20), using image analysis A higher proportion score and immunoreactive score for PD-L1+ and FoxP3+ Tregs was found in OSCC and dysplastic groups when compared to the nondysplastic control group (P <.05). There was no significant difference between the OSCC and dysplastic tissues. Significantly more PD-L1+ cells and Tregs were detected in dysplastic and OSCC tissues. An increase in PD-L1 and FoxP3 expression may serve as an indicator of progression from normal to a potentially malignant lesion. [ABSTRACT FROM AUTHOR]

Nerve sheath myxomas are rare, benign neoplasms of nerve sheath origin. They are often found arising from the dermis and subcutaneous tissues at the head and neck region. However, presentation in the oral cavity is rather unusual. We report a case of a 33-year-old woman who presented with a 12-month history of an extensively large, firm swelling in the left buccal space extending to the retromolar area, resulting in a slight facial asymmetry. A well-defined radiopaque mass was seen on magnetic resonance imaging studies. The diagnosis of oral nerve sheath myxoma was established, adding to the literature its incidence and subsequently improving understanding of its clinicopathologic features, histogenesis, and distinct entity relative to other oral lesions that can mimic its presentation. [ABSTRACT FROM AUTHOR]

Populations are aging worldwide, and older people are more likely to take medications and undergo treatment leading to side effects such as salivary gland hypofunction. It is not known how reduced salivary flow in older people affects the Candida albicans strains colonizing the oral cavity. The presence of resistant Candida strains could be debilitating for immunocompromised older people. The aim of this study was to compare C. albicans strains colonizing the mouths of older people with low and normal salivary flow. Participants aged 65 and above (n = 50) were examined, and their salivary flow rates (SFRs) were determined. Swabs and smears of the palate and tongue and saliva samples were collected. Smear products were stained with periodic acid-Schiff (PAS). Yeasts were cultured, quantified, and presumptively identified using CHROMagar Candida agar. Multilocus sequence typing was used to compare C. albicans strains. Twenty-four participants had a low SFR (<0.2 mL/min), whereas 26 participants had normal SFR (≥0.2 mL/min). A larger proportion of participants with low SFR had yeast-positive saliva (95% vs 52%), were highly colonized (>400 CFU/mL saliva) (68% vs 38%), presented with more PAS-positive smears (47% vs 19%), and had more C. albicans strains with evidence of microevolution (8 of 12 participants vs 1 of 5 participants) than those with normal salivary flow. Increased yeast presence in older people with low salivary flow was confirmed. There was a link between SFR and microevolution of C. albicans. The genetic changes may be because C. albicans is under pressure to adapt to a low-saliva environment. [ABSTRACT FROM AUTHOR]

Exosomes are membrane-bound nanovesicles released by cells into their extracellular environment. Exosomes influence cancer metastasis. The RNA levels of oncogenes within exosomes derived from cancer cells may thus provide a useful source for monitoring cancer progression and deploying early intervention. To compare the RNA levels of FOXM1, DNMT1, HOXA7, CCNB1, and HSPA1A in exosomes from normal primary gingival keratinocyte (PGK) and oral squamous cell carcinoma (OSCC) cell lines. Exosomes derived from PGK and OSCC cell lines (SCC4 and SCC25) were isolated using ultracentrifugation and their presence was confirmed by transmission electron cryomicroscopy. The exosomal RNA was extracted and subjected to reverse transcription quantitative polymerase chain reaction for mRNA analysis. Transmission electron cryomicroscopy revealed bilayered structures measuring 50 to 200 nm, consistent with the expected size of exosomes. Transcripts for the genes of interest were detected in the OSCC cells (mean 2−ΔCT: 0.1563, 0.0111, 0.011, 0.1062, and 0.58, respectively) and exosomes (mean 2−ΔCT: 0.3564, 0.0036, 0.0458, 0.0718, and 0.7252, respectively). HOXA7 was not detected in PGK. Of the remaining genes of interest, more RNA was detected in the OSCC cells (mean fold upregulations of 4.44, 2.80, 2.28, and 2.90, respectively) and OSCC exosomes (mean fold upregulations of 6.33, 2.20, 3.16, and 5.75, respectively) when compared with the PGK cells and exosomes. The results provide the first evidence that there is more FOXM1 and HSPA1A RNA in OSCC exosomes compared with PGK exosomes. These results will be used for ex vivo studies comparing exosomes in saliva and blood samples from patients with and without OSCC. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The aim of this study was to investigate the use of field emission scanning electron microscopy and electron dispersive spectrography (SEM-EDS) to identify silver solder 'tattoo.' STUDY DESIGN: SEM-EDS was used to analyze material present in the connective tissue of a patient who presented with bilateral pigmentation of the mandibular lingual gingiva adjacent to the first molars. No dental restorations were present. RESULTS: SEM-EDS analysis identified silver, with no evidence of tin, copper, or mercury. The patient was wearing an orthodontic appliance where brackets had been soldered to the archwire with silver solder. It is hypothesed that the solder underwent electrolytic corrosion with subsequent regrouping of silver ions in the submucosa leading to blue-gray discoloration. CONCLUSION: Spectrography proved to be a powerful diagnostic tool in identifying the metal within the oral mucosa. Attention is drawn to this newly described lesion, which should be included as a differential diagnosis for pigmented oral mucosal lesions. [ABSTRACT FROM AUTHOR]