Phenformin activates ER stress to promote autophagic cell death via NIBAN1 and DDIT4 in oral squamous cell carcinoma independent of AMPK.

The efficient clinical treatment of oral squamous cell carcinoma (OSCC) is still a challenge that demands the development of effective new drugs. Phenformin has been shown to produce more potent anti-tumor activities than metformin on different tumors, however, not much is known about the influence of phenformin on OSCC cells. We found that phenformin suppresses OSCC cell proliferation, and promotes OSCC cell autophagy and apoptosis to significantly inhibit OSCC cell growth both in vivo and in vitro. RNA-seq analysis revealed that autophagy pathways were the main targets of phenformin and identified two new targets DDIT4 (DNA damage inducible transcript 4) and NIBAN1 (niban apoptosis regulator 1). We found that phenformin significantly induces the expression of both DDIT4 and NIBAN1 to promote OSCC autophagy. Further, the enhanced expression of DDIT4 and NIBAN1 elicited by phenformin was not blocked by the knockdown of AMPK but was suppressed by the knockdown of transcription factor ATF4 (activation transcription factor 4), which was induced by phenformin treatment in OSCC cells. Mechanistically, these results revealed that phenformin triggers endoplasmic reticulum (ER) stress to activate PERK (protein kinase R-like ER kinase), which phosphorylates the transitional initial factor eIF2, and the increased phosphorylation of eIF2 leads to the increased translation of ATF4. In summary, we discovered that phenformin induces its new targets DDIT4 and especially NIBAN1 to promote autophagic and apoptotic cell death to suppress OSCC cell growth. Our study supports the potential clinical utility of phenformin for OSCC treatment in the future.

CSChighE-cadherinlow immunohistochemistry panel predicts poor prognosis in oral squamous cell carcinoma.

Identifying marker combinations for robust prognostic validation in primary tumour compartments remains challenging. We aimed to assess the prognostic significance of CSC markers (ALDH1, CD44, p75NTR, BMI-1) and E-cadherin biomarkers in OSCC. We analysed 94 primary OSCC and 67 metastatic lymph node samples, including central and invasive tumour fronts (ITF), along with clinicopathological data. We observed an increase in ALDH1+/CD44+/BMI-1- tumour cells in metastatic lesions compared to primary tumours. Multivariate analysis highlighted that elevated p75NTR levels (at ITF) and reduced E-cadherin expression (at the tumour centre) independently predicted metastasis, whilst ALDH1high exhibited independent predictive lower survival at the ITF, surpassing the efficacy of traditional tumour staging. Then, specifically at the ITF, profiles characterized by CSChighE-cadherinlow (ALDH1highp75NTRhighE-cadherinlow) and CSCintermediateE-cadherinlow (ALDH1 or p75NTRhighE-cadherinlow) were significantly associated with worsened overall survival and increased likelihood of metastasis in OSCC patients. In summary, our study revealed diverse tumour cell profiles in OSCC tissues, with varying CSC and E-cadherin marker patterns across primary tumours and metastatic sites. Given the pivotal role of reduced survival rates as an indicator of unfavourable prognosis, the immunohistochemistry profile identified as CSChighE-cadherinlow at the ITF of primary tumours, emerges as a preferred prognostic marker closely linked to adverse outcomes in OSCC.

Chaga mushroom extract suppresses oral cancer cell growth via inhibition of energy metabolism.

Oral cancer stands as a prevalent maligancy worldwide; however, its therapeutic potential is limited by undesired effects and complications. As a medicinal edible fungus, Chaga mushroom (Inonotus obliquus) exhibits anticancer effects across diverse cancers. Yet, the precise mechanisms underlying its efficacy remain unclear. We explored the detailed mechanisms underlying the anticancer action of Chaga mushroom extract in oral cancer cells (HSC-4). Following treatment with Chaga mushroom extracts, we analyzed cell viability, proliferation capacity, glycolysis, mitochondrial respiration, and apoptosis. Our findings revealed that the extract reduced cell viability and proliferation of HSC-4 cells while arresting their cell cycle via suppression of STAT3 activity. Regarding energy metabolism, Chaga mushroom extract inhibited glycolysis and mitochondrial membrane potential in HSC-4 cells, thereby triggering autophagy-mediated apoptotic cell death through activation of the p38 MAPK and NF-κB signaling pathways. Our results indicate that Chaga mushroom extract impedes oral cancer cell progression, by inhibiting cell cycle and proliferation, suppressing cancer cell energy metabolism, and promoting autophagy-mediated apoptotic cell death. These findings suggest that this extract is a promising supplementary medicine for the treatment of patients with oral cancer.

An Update on the Use of Artificial Intelligence in Digital Pathology for Oral Epithelial Dysplasia Research.

INTRODUCTION: Oral epithelial dysplasia (OED) is a precancerous histopathological finding which is considered the most important prognostic indicator for determining the risk of malignant transformation into oral squamous cell carcinoma (OSCC). The gold standard for diagnosis and grading of OED is through histopathological examination, which is subject to inter- and intra-observer variability, impacting accurate diagnosis and prognosis. The aim of this review article is to examine the current advances in digital pathology for artificial intelligence (AI) applications used for OED diagnosis. MATERIALS AND METHODS: We included studies that used AI for diagnosis, grading, or prognosis of OED on histopathology images or intraoral clinical images. Studies utilizing imaging modalities other than routine light microscopy (e.g., scanning electron microscopy), or immunohistochemistry-stained histology slides, or immunofluorescence were excluded from the study. Studies not focusing on oral dysplasia grading and diagnosis, e.g., to discriminate OSCC from normal epithelial tissue were also excluded. RESULTS: A total of 24 studies were included in this review. Nineteen studies utilized deep learning (DL) convolutional neural networks for histopathological OED analysis, and 4 used machine learning (ML) models. Studies were summarized by AI method, main study outcomes, predictive value for malignant transformation, strengths, and limitations. CONCLUSION: ML/DL studies for OED grading and prediction of malignant transformation are emerging as promising adjunctive tools in the field of digital pathology. These adjunctive objective tools can ultimately aid the pathologist in more accurate diagnosis and prognosis prediction. However, further supportive studies that focus on generalization, explainable decisions, and prognosis prediction are needed.

Challenges in the Assessment of Medullary Bone Invasion in Oral Cavity Cancers and Its Prognostic Significance.

BACKGROUND: As per AJCC 8th edition TNM staging system, bone invasion is a poor prognostic marker that upstages oral cavity squamous carcinoma (OSCC) to pT4a. Cortical erosion alone of bone or tooth socket by a gingival primary is not sufficient to upstage a tumour. The differentiation of cortical erosion from invasion through the cortical bone into the medulla is often challenging, limiting accurate staging. This review aims to assess the difficulties in differentiating cortical erosion from medullary invasion and evaluate the prognostic significance of different patterns of bone involvement. METHODS: A retrospective review of OSCC with primary curative surgery and bone resection treated at a single-center over 10 years, was performed to assess the prognostic significance of bone invasion. Hematoxylin-eosin stained slides of a subset of cases were re-reviewed in a planned manner to assess difficulties in precise categorization (no invasion/erosion/cortical invasion and medullary invasion), evaluate interobserver agreement, and correlate with clinical outcome. RESULTS: Five hundred and ninety patients were included, with a median follow-up of 28 months. On univariate analysis, the 3-year local, nodal and distant metastasis control were not significantly different in the 3 groups of no invasion, erosion, and invasion (p = 0.43, 0.47, and 0.47, respectively). Overall survival (OS) at 3 years was 78.1% and disease-free-survival(DFS) was 63.7% in the entire cohort. On univariate analysis, there was significant difference in OS and DFS based on these groups. This did not translate into independent prognostic benefit on multivariable analysis (p = 0.75 and 0.19, respectively). The independent prognostic factors were margin positivity, tumor differentiation, perineural invasion and pathological nodal involvement. Planned re-review of a subset of 202 cases resulted in a change in bone involvement category in 26/202 cases, which was mainly due to difficulty in assessing cortico-medullary junction near the tooth socket and bone fragmentation. The assessment showed moderate to near complete agreement (kappa 0.59-0.82) between 2 observers. CONCLUSION: Our study shows that bone involvement is not an independent prognostic marker and there is no specific correlation of medullary invasion with outcome over those that showed cortical erosion. Several factors contribute to difficulties and interobserver variability in assessing bone involvement.

WNT3 promotes chemoresistance to 5-Fluorouracil in oral squamous cell carcinoma via activating the canonical ß-catenin pathway.

BACKGROUND: 5-Fluorouracil (5FU) is a primary chemotherapeutic agent used to treat oral squamous cell carcinoma (OSCC). However, the development of drug resistance has significantly limited its clinical application. Therefore, there is an urgent need to determine the mechanisms underlying drug resistance and identify effective targets. In recent years, the Wingless and Int-1 (WNT) signaling pathway has been increasingly studied in cancer drug resistance; however, the role of WNT3, a ligand of the canonical WNT signaling pathway, in OSCC 5FU-resistance is not clear. This study delved into this potential connection. METHODS: 5FU-resistant cell lines were established by gradually elevating the drug concentration in the culture medium. Differential gene expressions between parental and resistant cells underwent RNA sequencing analysis, which was then substantiated via Real-time quantitative PCR (RT-qPCR) and western blot tests. The influence of the WNT signaling on OSCC chemoresistance was ascertained through WNT3 knockdown or overexpression. The WNT inhibitor methyl 3-benzoate (MSAB) was probed for its capacity to boost 5FU efficacy. RESULTS: In this study, the WNT/ß-catenin signaling pathway was notably activated in 5FU-resistant OSCC cell lines, which was confirmed through transcriptome sequencing analysis, RT-qPCR, and western blot verification. Additionally, the key ligand responsible for pathway activation, WNT3, was identified. By knocking down WNT3 in resistant cells or overexpressing WNT3 in parental cells, we found that WNT3 promoted 5FU-resistance in OSCC. In addition, the WNT inhibitor MSAB reversed 5FU-resistance in OSCC cells. CONCLUSIONS: These data underscored the activation of the WNT/ß-catenin signaling pathway in resistant cells and identified the promoting effect of WNT3 upregulation on 5FU-resistance in oral squamous carcinoma. This may provide a new therapeutic strategy for reversing 5FU-resistance in OSCC cells.

Systematic review of minimally-invasive reconstructive options for oral cavity defects.

The oral cavity is a primary site for malignant neoplasms of the head and neck region. Surgery, with or without adjuvant therapy, offers the highest probability of cure by focusing on radical tumour removal and organ function restoration. Reconstructive options are represented by local and free flaps, while small defects can be managed without reconstruction. For medium-sized defects without bone involvement, local flaps can be a good alternative to free flaps in selected patients. The purposes of this article are to analyse the main minimally-invasive reconstructive techniques in oral cancer surgery through a systematic review of the literature and develop a reconstructive algorithm based on the site and size of the defect. We defined minimally-invasive reconstruction as any reconstructive option not involving flap dissection from the neck or other distant areas from the oral cavity. Options considered include: local myo-mucosal or mucosal flaps (based on the facial or buccal arteries, and palatal flap), Bichat's fat pad flap, and nasolabial flap. Use of biological or synthetic materials is also described. In selected patients with small to moderate-sized defects, the possibility of reconstruction with local flaps can be a viable option.

Acinetobacter baumannii as an oro-dental pathogen: a red alert!!

OBJECTIVES: This review highlights the existence and association of Acinetobacter baumannii with the oro-dental diseases, transforming this systemic pathogen into an oral pathogen. The review also hypothesizes possible reasons for the categorization of this pathogen as code blue due to its stealthy entry into the oral cavity. METHODOLOGY: Study data were retrieved from various search engines reporting specifically on the association of A. baumannii in dental diseases and tray set-ups. Articles were also examined regarding obtained outcomes on A. baumannii biofilm formation, iron acquisitions, magnitude of antimicrobial resistance, and its role in the oral cancers. RESULTS: A. baumannii is associated with the oro-dental diseases and various virulence factors attribute for the establishment and progression of oro-mucosal infections. Its presence in the oral cavity is frequent in oral microbiomes, conditions of impaired host immunity, age related illnesses, and hospitalized individuals. Many sources also contribute for its prevalence in the dental health care environment and the presence of drug resistant traits is also observed. Its association with oral cancers and oral squamous cell carcinoma is also evident. CONCLUSIONS: The review calls for awareness on the emergence of A. baumannii in dental clinics and for the need for educational programs to monitor and control the sudden outbreaks of such virulent and resistant traits in the dental health care settings.

Diagnostic accuracy of contrast-enhanced computed tomography in assessing bone invasion in patients with oral squamous cell carcinoma.

OBJECTIVES: This study aimed to evaluate the diagnostic accuracy of contrast-enhanced computed tomography (CT) in detecting bone invasion in oral squamous cell carcinoma (OSCC) patients and to explore clinicopathological factors associated with its reliability. MATERIALS AND METHODS: 417 patients underwent preoperative contrast-enhanced CT followed by radical surgery. The presence or absence of bone invasion served as the outcome variable, with histopathologic examination of the resection specimen considered the gold standard. Statistical analyses, comprising correlation analyses and the determination of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were conducted. RESULTS: CT exhibited 76.85% sensitivity, 82.20% specificity, 47.14% PPV, and 89.67% NPV. False-positive and false-negative rates were 11.27% and 5.99%, respectively. Artifacts affected assessment in 44 patients, but not in those with bone invasion. Tumor size, depth of invasion (DOI), tumor localization at the upper jaw, lymphatic invasion, and perineural invasion correlated with incorrect identification of bone invasion (Chi-square, p < 0.05). CONCLUSIONS: Despite utilizing thin-section CT, notable false-positive and false-negative results persisted. Patients with T3 tumors, DOI ≥ 10 mm, or upper jaw tumors are at higher risk for misidentification of bone invasion. Combining multiple methods may enhance diagnostic accuracy, and the integration of artificial intelligence or tracking electrolyte disturbances by tumor depth profiling shows promise for further assessment of bone invasion before histopathology. CLINICAL RELEVANCE: Surgeons should consider these insights when planning tumor resection. Supplementary imaging may be warranted in cases with high risk factors for misidentification. Further methodological advancements are crucial for enhancing diagnostic precision.

Periodontitis and the risk of oral cancer: a meta-analysis of case-control studies.

OBJECTIVE: The current studies have yielded inconclusive findings regarding the connection between periodontitis  and oral cancer (OC). Therefore, our goal is to elucidate this relationship. MATERIALS AND METHODS: We conducted a thorough search of electronic databases (EMBASE, PubMed, Web of Science, and Cochrane Library) up to September 2023. The Newcastle-Ottawa Scale (NOS) was applied to assess study quality. To evaluate potential publication bias, both a funnel plot and Egger's test were employed. Additionally, a sensitivity analysis was conducted to explore the source of heterogeneity when the I2 statistic exceeded 50%. RESULTS: This systematic review encompassed 16 studies, involving a total of 6,032 OC patients and 7,432 healthy controls. Our meta-analysis, incorporating data from nine studies, revealed a significant correlation between periodontitis and the risk of OC (OR [odds ratio] = 2.94, 95% CI [confidence interval] (2.13, 4.07); five studies, 6,927 participants; low certainty of evidence). Findings also suggested that individuals with more than 15 missing teeth may have a heightened risk of OC (OR = 1.91, 95% CI (1.01, 3.62)). Furthermore, clinical attachment loss (CAL) and decayed, missing, and filled teeth (DMFT) in OC patients were more pronounced compared to the control group (CAL, SMD = 1.94, 95% CI (0.22, 3.66); DMFT, SMD = 0.65, 95% CI (0.12, 1.18)). CONCLUSION: Periodontitis may serve as a potential risk factor for OC. However, caution is warranted in interpreting these findings due to the substantial level of heterogeneity.

EP4-induced mitochondrial localization and cell migration mediated by CALML6 in human oral squamous cell carcinoma.

Lymph node metastasis, primarily caused by the migration of oral squamous cell carcinoma (OSCC) cells, stands as a crucial prognostic marker. We have previously demonstrated that EP4, a subtype of the prostaglandin E2 (PGE2) receptor, orchestrates OSCC cell migration via Ca2+ signaling. The exact mechanisms by which EP4 influences cell migration through Ca2+ signaling, however, is unclear. Our study aims to clarify how EP4 controls OSCC cell migration through this pathway. We find that activating EP4 with an agonist (ONO-AE1-473) increased intracellular Ca2+ levels and the migration of human oral cancer cells (HSC-3), but not human gingival fibroblasts (HGnF). Further RNA sequencing linked EP4 to calmodulin-like protein 6 (CALML6), whose role remains undefined in OSCC. Through protein-protein interaction network analysis, a strong connection is identified between CALML6 and calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2), with EP4 activation also boosting mitochondrial function. Overexpressing EP4 in HSC-3 cells increases experimental lung metastasis in mice, whereas inhibiting CaMKK2 with STO-609 markedly lowers these metastases. This positions CaMKK2 as a potential new target for treating OSCC metastasis. Our findings highlight CALML6 as a pivotal regulator in EP4-driven mitochondrial respiration, affecting cell migration and metastasis via the CaMKK2 pathway.

The involvement of epidermal growth factor receptor/protein kinase B signaling in the tumor intrinsic PD-L1-induced malignant potential of oral squamous cell carcinoma.

BACKGROUND: Various antigen-presenting cells and tumor cells-expressing PD-L1 inhibits antitumor immune responses in the tumor microenvironment. Recently, numerous studies have shown that tumor cell intrinsic PD-L1 also plays important roles in tumor growth and progression. On the other hand, oral squamous cell carcinoma (OSCC) cells overexpress epidermal growth factor receptor (EGFR) and EGFR signal pathway exacerbates tumor progression. Therefore, this study assessed whether tumor-intrinsic PD-L1 facilitates malignant potential of OSCC cells through regulation of EGFR signaling. METHODS: Two OSCC cell lines, SAS and HSC-3, were transfected with PD-L1 and EGFR-specific small interfering RNA (siRNA). Influences of PD-L1 knockdown on malignant potentials of OSCC cells were examined by Cell Counting kit-8 assay, transwell assay, sphere formation assay, flow cytometry, and Western blot. Effects of PD-L1 and EGFR knockdown on each expression were examined by quantitative real-time PCR (qRT-PCR), Western blot, and flow cytometry. RESULTS: Transfection of an PD-L1-siRNA into OSCC cells decreased the abilities of proliferation, stemness, and mobility of these cells significantly. PD-L1 knockdown also decreased EGFR expression through the promotion of proteasome- and lysosome-mediated degradation and following activation of the EGFR/protekin kinase B (AKT) signal pathway. Meanwhile, EGFR knockdown did not influence PD-L1 expression in SAS and HSC-3 cells, but treatment with a recombinant human EGF induced its expression. Treatment with erlotinib and cetuximab suppressed rhEGF-induced PD-L1 expression and localization in the cellular membrane of both OSCC cells. CONCLUSION: OSCC cells-expressing PD-L1 induced by EGF stimulation may promote malignancy intrinsically via the activation of the EGFR/AKT signaling cascade.

Use of digital strategies in the diagnosis of oral squamous cell carcinoma: a scoping review.

Telediagnosis uses information and communication technologies to support diagnosis, shortening geographical distances. It helps make decisions about various oral lesions. The objective of this scoping review was to map the existing literature on digital strategies to assist in the diagnosis of oral squamous cell carcinoma. this review was structured based on the 5-stage methodology proposed by Arksey and O'Malley, the Joanna Briggs Institute Manual for Evidence Synthesis and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews. The methods were registered on the Open Science Framework. The research question was: What digital strategies have been used to assist in the diagnosis of oral squamous cell carcinoma? The search was conducted on PubMed/MEDLINE, Scopus, Web of Science, Embase, and ScienceDirect. Inclusion criteria comprised studies on telediagnosis, teleconsultation or teleconsultation mediated by a professional and studies in English, without date restrictions. The search conducted in June 2023 yielded 1,798 articles, from which 16 studies were included. Telediagnosis was reported in nine studies, involving data screening through applications, clinical images from digital cameras, mobile phones or artificial intelligence. Histopathological images were reported in four studies. Both, telediagnosis and teleconsultation, were mentioned in seven studies, utilizing images and information submission services to platforms, WhatsApp or applications. One study presented teleconsultations involving slides and another study introduced teleconsultation mediated by a professional. Digital strategies telediagnosis and teleconsultations enable the histopathological diagnosis of oral cancer through clinical or histopathological images. The higher the observed diagnostic agreement, the better the performance of the strategy.

In Response to "Acute Oral Mucositis During Hypo-Fractionated Radiation in Squamous Cell Carcinoma of Oral Cavity".

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Revisiting the "Puffed Cheek" Technique: Advantages, Fallacies, and Potential Solutions.

The "puffed cheek" technique is routinely performed during CT neck studies in patients with suspected oral cavity cancers. The insufflation of air within the oral vestibule helps in the detection of small buccal mucosal lesions, with better delineation of lesion origin, depth, and extent of spread. The pitfalls associated with this technique are often underrecognized and poorly understood. They can mimic actual lesions, forfeiting the technique's primary purpose. This review provides an overview of the puffed cheek technique and its associated pitfalls. These pitfalls include pneumoparotid, soft palate elevation that resembles a nasopharyngeal mass, various tongue displacements or distortions that obscure tongue lesions or mimic them, sublingual gland herniation, an apparent exacerbation of the airway edema, vocal cord adduction that hinders glottic evaluation, and false indications of osteochondronecrosis in laryngeal cartilage. Most stem from a common underlying mechanism of unintentional Valsalva maneuver engaged in by the patient while trying to perform a puffed cheek, creating a closed air column under positive pressure with resultant surrounding soft-tissue displacement. These pitfalls can thus be avoided by instructing the patient to maintain continuous nasal breathing while puffing out their cheek during image acquisition, preventing the formation of the closed air column. Keywords: CT, Head/Neck © RSNA, 2024.

Survival estimation of oral cancer using fuzzy deep learning.

BACKGROUND: Oral cancer is a deadly disease and a major cause of morbidity and mortality worldwide. The purpose of this study was to develop a fuzzy deep learning (FDL)-based model to estimate the survival time based on clinicopathologic data of oral cancer. METHODS: Electronic medical records of 581 oral squamous cell carcinoma (OSCC) patients, treated with surgery with or without radiochemotherapy, were collected retrospectively from the Oral and Maxillofacial Surgery Clinic and the Regional Cancer Center from 2011 to 2019. The deep learning (DL) model was trained to classify survival time classes based on clinicopathologic data. Fuzzy logic was integrated into the DL model and trained to create FDL-based models to estimate the survival time classes. RESULTS: The performance of the models was evaluated on a test dataset. The performance of the DL and FDL models for estimation of survival time achieved an accuracy of 0.74 and 0.97 and an area under the receiver operating characteristic (AUC) curve of 0.84 to 1.00 and 1.00, respectively. CONCLUSIONS: The integration of fuzzy logic into DL models could improve the accuracy to estimate survival time based on clinicopathologic data of oral cancer.

F. Nucleatum enhances oral squamous cell carcinoma proliferation via E-cadherin/ß-Catenin pathway.

BACKGROUND: Fusobacterium nucleatum (F. nucleatum) is a microbial risk factor whose presence increases the risk of oral squamous cell carcinoma (OSCC) progression. However, whether it can promote the proliferation of OSCC cells remains unknown. METHODS: In this study, we investigated F. nucleatum effect on OSCC cell proliferation using in vitro and in vivo experiments. RESULTS: Our results showed that F. nucleatum promoted OSCC cell proliferation, doubling the cell count after 72 h (CCK-8 assay). Cell cycle analysis revealed G2/M phase arrest. F. nucleatum interaction with CDH1 triggered phosphorylation, upregulating downstream protein ß-catenin and activating cyclinD1 and Myc. Notably, F. nucleatum did not affect noncancerous cells, unrelated to CDH1 expression levels in CAL27 cells. Overexpression of phosphorylated CDH1 in 293T cells did not upregulate ß-catenin and cycle-related genes. In vivo BALB/c nude experiments showed increased tumor volume and Ki-67 proliferation index after F. nucleatum intervention. CONCLUSION: Our study suggests that F. nucleatum promotes OSCC cell proliferation through the CDH1/ß-catenin pathway, advancing our understanding of its role in OSCC progression and highlighting its potential as a therapeutic target.

Extracellular vesicles from Aggregatibacter actinomycetemcomitans exhibit potential antitumorigenic effects in oral cancer: a comparative in vitro study.

Aggregatibacter actinomycetemcomitans is an opportunistic Gram-negative periodontopathogen strongly associated with periodontitis and infective endocarditis. Recent evidence suggests that periodontopathogens can influence the initiation and progression of oral squamous cell carcinoma (OSCC). Herein we aimed to investigate the effect of A. actinomycetemcomitans-derived extracellular vesicles (EVs) on OSCC cell behavior compared with EVs from periodontopathogens known to associate with carcinogenesis. EVs were isolated from: A. actinomycetemcomitans and its mutant strains lacking the cytolethal distending toxin (CDT) or lipopolysaccharide (LPS) O-antigen; Porphyromonas gingivalis; Fusobacterium nucleatum; and Parvimonas micra. The effect of EVs on primary and metastatic OSCC cells was assessed using cell proliferation, apoptosis, migration, invasion, and tubulogenesis assays. A. actinomycetemcomitans-derived EVs reduced the metastatic cancer cell proliferation, invasion, tubulogenesis, and increased apoptosis, mostly in CDT- and LPS O-antigen-dependent manner. EVs from F. nucleatum impaired the metastatic cancer cell proliferation and induced the apoptosis rates in all OSCC cell lines. EVs enhanced cancer cell migration regardless of bacterial species. In sum, this is the first study demonstrating the influence of A. actinomycetemcomitans-derived EVs on oral cancer in comparison with other periodontopathogens. Our findings revealed a potential antitumorigenic effect of these EVs on metastatic OSCC cells, which warrants further in vivo investigations.

Prevalence of high-risk human papillomavirus in oral squamous cell carcinoma with or without chewing habits.

Oral cancer (OC) is the most common cancer in Pakistani males and the second most common in females. Major risk factors include peculiar chewing habits, human papillomavirus (HPV) infection and molecular pathways. However, less data is available for this avertible cancer regarding its association with high-risk HPV (HR-HPV) and chewing habits in this region. Therefore, this study was done to determine the prevalence of HR-HPV in oral squamous cell carcinoma (OSCC) and its correlation with p16 and chewing habits. Formalin-fixed paraffin-embedded (FFPE) biopsy specimens of 186 samples were tested for HR-HPV type 16/18 by PCR, followed by p16 immunostaining (IHC) in a subset of cases (n = 50). Appropriate statistical tests were applied to find the association between HR-HPV/p16 and peculiar chewing habits with significance criteria of p<0.05 with 95% CI. HR-HPV (type 16 &18) was present in seven out of 186 cases (3.8%). Of these seven cases, five were positive for HPV16, whereas two were positive for HPV16/18. The overall expression of p16 protein in 50 samples was 38% (n = 19), and among these 19-IHC positive samples, 26% were positive for HR-HPV DNA. No significant association was found between HR-HPV positivity and p16 and chewing habits (p>0.05). It was concluded that HR-HPV prevalence in OSCC was very low in our population, with no statistically significant correlation with p16 and chewing habits. These results suggest the role of HR-HPV as an independent risk factor in OSCC in the local setting.

Metastatic sarcomas of the oral cavity: A systematic review.

Oral metastatic sarcomas (OMSs) occur only occasionally, and information about their characteristics is based on the restricted number of cases reported in the literature. This study aims to systematically review the English literature to recognize the clinicopathologic characteristics of OMSs. An electronic search was performed in PubMed Central and Scopus databases. The search included all the published articles (human case reports and case series) up till April 2023, with no time restrictions. OMSs were slightly more prevalent in males in their fifth to seventh decades of life. However, a high percentage of OMSs has been reported in the second decade of life. Lower extremities, breasts and uterus are the most common primary origin of metastatic sarcoma. Gingiva and mandible were common locations in the oral cavity for metastatic deposits. Generally, they demonstrated widespread affliction. The mean time interval between primary tumor detection and diagnosis of the oral metastasis was about 33.54 ± 36.19 months. Death was reported in 83 patients (67.48 %) with a mean survival rate of 7.98 ± 10.30 months. The most common microscopic tumor types were leiomyosarcoma (n = 21, 17 %), followed by angiosarcoma (n = 20, 16.26 %) and osteosarcoma (n = 18, 14.63 %). In conclusion, while oral metastases of sarcomas are not common, those should be considered in the differential diagnosis of the oral lesions. Although OMSs show a high occurrence in the 7th decade of the life, the average age of patients with oral involvement is lower than the overall metastatic lesions. OMSs may present as widespread disease with poor prognosis.