Floor of mouth schwannoma mimicking a salivary gland neoplasm: a report of the case and review of the literature.

Schwannomas or neurilemmomas are slow-growing, benign and often firm lumps that are typically painless. They are extremely rare in the oral cavity, with the tongue and the palate being the most common intraoral sites. This is a case report of this pathology in the floor of the mouth. We present a case of a 28-year-old female patient with a 2-month history of a floor of mouth swelling. On clinical examination this was non-tender and appeared firm. An ultrasound of the lesion was performed which revealed a well-defined, rounded and low reflective soft tissue mass. Following an MRI scan and surgical excision of the lesion, a definitive diagnosis of a schwannoma was made. The presence of schwannoma in the oral cavity is unusual. Based on the literature and the presented case, it should be considered as a differential diagnosis until the final histopathological confirmation.

Non-sebaceous lymphadenoma of the submandibular gland: diagnostic challenges in the head and neck cancer pathway.

Non-sebaceous lymphadenoma (NSLA) is a rare benign salivary gland tumour with lymphoid and epithelial components and without sebaceous differentiation. The large majority of the reported cases arise within the parotid gland. We present an NSLA arising from the submandibular gland. The tumour presented as a painless longstanding neck lump. Ultrasound, fine needle aspiration, MRI and positron emission tomography found features supportive of squamous cell carcinoma. The patient was treated with surgery for oropharyngeal carcinoma of unknown origin, in accordance with local and national guidelines. The final histological assessment revealed the level Ib neck lesion to be NSLA. Although a rare occurrence, these lesions may pose a diagnostic challenge in the head and neck cancer pathway.

Areca nut alkaloids induce irreparable DNA damage and senescence in fibroblasts and may create a favourable environment for tumour progression.

BACKGROUND: Oral submucous fibrosis (OSMF) is a pre-malignant condition that is strongly associated with the areca nut alkaloids, arecoline (ARC) and arecaidine (ARD). The condition is characterised by the presence of senescent fibroblasts in the subepithelial mesenchyme which have the potential to promote malignancy in the neighbouring epithelial cells. We tested the hypothesis that areca nut alkaloids induce senescence in oral fibroblasts and promote the secretion of invasion-promoting transforming growth factor ß (TGF-ß) and matrix metalloproteinase-2 (MMP-2). METHODS: Two oral fibroblast lines were treated for 48h with ARC and ARD. Senescence-associated ß-galactosidase (SA-ßGal) activity, Ki67 (cycling cells), large 53BP1 foci (irreparable DNA strand breaks) and p16(INK) (4A) (late senescence) were used as markers of cellular senescence and were quantified using indirect immunofluorescence and the ImageJ program. TGF-ß and MMP-2 levels were measured using ELISA. Statistical analyses were performed with the two-tailed unpaired t-test where n = 3 and the Wilcoxon-Mann-Whitney test where n = 6. RESULTS: ARC (100 and 300 µM) and ARD (30 and 100 µM) significantly (P < 0.05) induced fibroblast senescence, as determined by the increased expression of SA-ßGal, 53BP1 staining and CDKN2A/p16(INK) (4A) ; there was also a non-significant reduction in Ki67 staining. Treated cells also showed a three- fivefold increase in TGF-ß and a small non-significant increase in MMP-2. CONCLUSIONS: Areca nut alkaloids induce senescence in oral fibroblasts and promote increased secretion of TGF-ß and perhaps MMP-2 that may create a tissue environment thought to be critical in the progression of OSMF to malignancy.

Biphenotypic human papillomavirus-associated head and neck squamous cell carcinoma: a report of two cases.

Human papillomavirus-associated oropharyngeal squamous cell carcinoma is now recognised as a subtype of head and neck cancer with distinct clinical, molecular and histological characteristics. The majority of these carcinomas are of non-keratinising squamous type but there is a growing number of histomorphologic variants of this disease. Here we describe the clinical, histomorphologic and immunophenotypic features of two cases of human papillomavirus-associated oropharyngeal squamous cell carcinoma demonstrating a clearly delineated biphasic differentiated and undifferentiated phenotype.

Senescent human fibroblasts show increased glycolysis and redox homeostasis with extracellular metabolomes that overlap with those of irreparable DNA damage, aging, and disease.

Cellular senescence can modulate various pathologies and is associated with irreparable DNA double-strand breaks (IrrDSBs). Extracellular senescence metabolomes (ESMs) were generated from fibroblasts rendered senescent by proliferative exhaustion (PEsen) or 20 Gy of γ rays (IrrDSBsen) and compared with those of young proliferating cells, confluent cells, quiescent cells, and cells exposed to repairable levels of DNA damage to identify novel noninvasive markers of senescent cells. ESMs of PEsen and IrrDSBsen overlapped and showed increased levels of citrate, molecules involved in oxidative stress, a sterol, monohydroxylipids, tryptophan metabolism, phospholipid, and nucleotide catabolism, as well as reduced levels of dipeptides containing branched chain amino acids. The ESM overlaps with the aging and disease body fluid metabolomes, supporting their utility in the noninvasive detection of human senescent cells in vivo and by implication the detection of a variety of human pathologies. Intracellular metabolites of senescent cells showed a relative increase in glycolysis, gluconeogenesis, the pentose-phosphate pathway, and, consistent with this, pyruvate dehydrogenase kinase transcripts. In contrast, tricarboxylic acid cycle enzyme transcript levels were unchanged and their metabolites were depleted. These results are surprising because glycolysis antagonizes senescence entry but are consistent with established senescent cells entering a state of low oxidative stress.

Progression of genotype-specific oral cancer leads to senescence of cancer-associated fibroblasts and is mediated by oxidative stress and TGF-ß.

Keratinocyte senescence acts as a barrier to tumor progression but appears to be lost in late pre-malignancy to yield genetically unstable oral squamous cell carcinomas (GU-OSCC); a subset of OSCC possessing wild-type p53 and are genetically stable (GS-OSCC). In this study, fibroblasts from GU-OSCC were senescent relative to fibroblasts from GS-OSCC, epithelial dysplastic tissues or normal oral mucosa, as demonstrated by increased senescence-associated ß-galactosidase (SA ß-Gal) activity and overexpression of p16(INK4A). Keratinocytes from GU-OSCC produced high levels of reactive oxygen species (ROS) and this was associated with an increase in the production of transforming growth factor-ß1 (TGF-ß1) and TGF-ß2 in stromal fibroblasts. Treatment of normal fibroblasts with keratinocyte conditioned media (CM) from GU-OSCC, but not GS-OSCC or dysplastic keratinocytes with dysfunctional p53, induced fibroblast senescence. This phenomenon was inhibited by antioxidants and anti-TGF-ß antibodies. Fibroblast activation by TGF-ß1 preceded cellular senescence and was associated with increased ROS levels; antioxidants inhibited this reaction. Senescent fibroblasts derived from GU-OSCC or normal fibroblasts treated with CM from GU-OSCC or hydrogen peroxide, but not non-senescent fibroblasts derived from GS-OSCC, promoted invasion of keratinocytes in vitro. Epithelial invasion was stimulated by fibroblast activation and amplified further by fibroblast senescence. The data demonstrate that malignant keratinocytes from GU-OSCC, but not their pre-malignant counterparts, produce high levels of ROS, which, in turn, increase TGF-ß1 expression and induce fibroblast activation and senescence in a p5-independent manner. Fibroblasts from GU-OSCC were particularly susceptible to oxidative DNA damage because of high levels of ROS production, downregulation of antioxidant genes and upregulation of pro-oxidant genes. The results demonstrate the functional diversity of cancer-associated fibroblasts and show that malignant keratinocytes from GU-OSCC reinforce their malignant behavior by inducing fibroblast activation and senescence through ROS and TGF-ß-dependent mechanisms.

Clinical and histopathologic parameters in survival of oral squamous cell carcinoma.

OBJECTIVE: The aim of this study was to assess the relevance of clinical and histopathologic parameters on survival of oral squamous cell carcinoma (OSCC) patients in Sri Lanka. STUDY DESIGN: A cohort of 193 previously diagnosed OSCC patients were followed for up to 5 years. Clinical and histopathologic parameters were analyzed regarding local recurrence and 5-year survival after treatment. RESULTS: Site, stage, local recurrence, degree of differentiation, degree of keratinization, pattern of invasion, and status of the excision margins showed a significant association with the 5-year survival (P < .05). Multivariate analysis identified stage, pattern of invasion, and status of the excision margins as true independent prognostic indicators of OSCC. Pattern of invasion was the best prognosticator of both local recurrence and overall survival in the Cox regression model (P < .001). CONCLUSIONS: Stage, pattern of invasion, and status of the excision margins are superior prognostic indicators of OSCC compared with other parameters.

Increased secretion of tissue inhibitors of metalloproteinases 1 and 2 (TIMPs -1 and -2) in fibroblasts are early indicators of oral sub-mucous fibrosis and ageing.

Oral submucous fibrosis (OSMF) is associated with paan chewing, altered collagen metabolism, inflammation and the upregulation of numerous cytokines. OSMF fibroblasts accumulate senescent cells at an increased rate because of increased reactive oxygen species production and DNA double-strand breaks (DDBs), generated intrinsically by damaged mitochondria. This results in a reduced replicative lifespan. However, it is still unclear which other changes are intrinsic to the fibroblasts and associated with OSMF rather than the paan chewing habit or the OSMF environment. Both the oral epithelium and the mesenchyme have elevated levels of TGF-ß(1) in OSMF in vivo. However, in cultured fibroblasts, secreted levels of TGF-ß(1,) other cytokines and the matrix metalloproteinases 1 and 2 showed no association with OSMF. In contrast, the tissue inhibitors of metalloproteinases, TIMP-1 and TIMP-2, were increased in 10/11 OSMF fibroblast cultures relative to normal and non-diseased paan user controls. OSMF fibroblast collagen levels were normal. TIMP levels correlated with replicative lifespan of the cultures but not with the presence of senescent cells, as senescent cell depletion in OSMF fibroblast cultures did not result in a reduction in either TIMP-1 or TIMP-2. However, the introduction of unrepairable DDBs into normal oral fibroblasts by ionizing radiation increased TIMP-1 and TIMP-2 secretion by two-fold and seven-fold, respectively, within 5 days, replicating early senescence and the elevation seen in OSMF cultures. Therefore, increased fibroblast TIMP-1/2 levels could be early disease-specific markers of OSMF onset, DDBs and ageing and may have clinical significance, as OSMF can be reversed in its early stages.

Senescent mesenchymal cells accumulate in human fibrosis by a telomere-independent mechanism and ameliorate fibrosis through matrix metalloproteinases.

Fibrosis can occur in many organs, where it is a debilitating and preneoplastic condition. The senescence of activated fibroblasts has been proposed to ameliorate fibrosis via the innate immune system but its role in humans has not been investigated. The availability of oral submucous fibrosis (OSMF) biopsies at different stages of disease progression allowed us to test the hypothesis that senescent fibroblasts accumulate with the progression of human fibrosis in vivo, and also to examine the mechanism of senescence. We tested the hypothesis that senescent cells may ameliorate fibrosis by increasing the secretion of matrix metalloproteinases (MMPs). We have used a combination of in situ immunodetection techniques, drug treatments, fluorescence-activated cell sorting and enzyme-linked absorbance assays on tissue samples and fibroblast cultures. We report a novel panning technique, based on fibronectin adhesion rates, to enrich and deplete senescent cells from fibroblast populations. Senescent fibroblasts, as determined by the presence of senescence-associated heterochromatic foci, accumulated with OSMF progression (R(2) = 0.98) and possessed a reduced replicative lifespan in vitro. Unlike wounds, however, OSMF fibroblasts were quiescent in vivo and consistent with this observation, possessed functional telomeres of normal length. Senescence was associated in vivo and in vitro with oxidative damage, DNA damage foci and p16(INK4A) accumulation and required the production of reactive oxygen species (ROS), perhaps from damaged mitochondria, but not the continuous presence of the disease stimulus (areca nut and tobacco), the tissue environment or other cell types. Depletion of OSMF fibroblasts of senescent cells showed that these cells accounted for 25-83 times more MMP-1 and -2 than their pre-senescent counterparts. The results show that the accumulation of senescent fibroblasts in human fibrosis occurs by a telomere-independent mechanism involving ROS and may locally ameliorate the condition by the increased expression of MMPs prior to clearance by the immune system.

Fibroblast gene expression profile reflects the stage of tumour progression in oral squamous cell carcinoma.

Oral cancer is a highly aggressive malignancy with poor prognosis. This study examined the behaviour of fibroblast strains from normal oral mucosa, dysplastic epithelial tissue, and genetically stable (minimal copy number alterations-CNA; minimal loss of heterozygosity-LOH; wild-type p53; wild-type p16INK4A) and unstable (extensive CNA and LOH; inactivation of p53 and p16INK4A) oral squamous cell carcinoma (OSCC). Fibroblasts from genetically unstable OSCC relative to the other fibroblast subtypes grew more slowly and stimulated the invasion of a non-tumourigenic keratinocyte cell line into fibroblast-rich collagen gels. To understand these findings, genome-wide transcriptional profiles were generated using the GeneChip(®) cDNA whole transcript microarray platform. Principal component analysis showed that the fibroblasts could be distinguished according to the stage of tumour development. Tumour progression was associated with down-regulation of cell cycle- and cytokinesis-related genes and up-regulation of genes encoding transmembrane proteins including cell adhesion molecules. Gene expression was validated in independent fibroblast strains using qRT-PCR. Gene connectivity and interactome-transcriptome associations were determined using a systems biology approach to interrogate the gene expression data. Clusters of gene signatures were identified that characterized genetically unstable and stable OSCCs relative to each other and to fibroblasts from normal oral mucosa. The expression of highly connected genes associated with unstable OSCCs, including those that encode α-SMA and the integrin α6, correlated with poor patient prognosis in an independent dataset of head and neck cancer. The results of this study demonstrate that fibroblasts from unstable OSCCs represent a phenotypically distinguishable subset that plays a major role in oral cancer biology.

Molecular markers in oral epithelial dysplasia: review.

The clinical and histologic features alone cannot accurately predict whether potentially malignant disorders of the oral mucosa remain stable, regress or progress to malignancy. Some of them, with or without epithelial dysplasia, may transform to invasive oral squamous cell carcinomas (OSCC). Identification of molecular markers which can predict disease progression is necessary to improve the management of these disorders. Many genes and signaling pathways have been shown to be involved in the development of OSCC. This review summarizes some molecular markers researched in the detection of pre-cancer. We highlight selected markers that are reported to be significantly associated with progression of potentially malignant disorders to OSCC. These include alterations in genes/pathways which control cellular signaling, cell cycle, apoptosis, genomic stability, cytoskeleton, angiogenesis, etc. However, these genetic tumor markers have so far not gained any use in routine diagnosis and their utility in the prediction of risk of malignant transformation remains unknown. It is, however, clear from the large number of studies, some described in this review, that multiple genes/pathways are involved in the progression from normal to metaplastic/dysplastic, and subsequently to cancer. It is therefore necessary to study those significant alterations in multiple genes simultaneously in biopsy samples from large cohorts of subjects.