Endoscopically-assisted intraoral resection of osteochondroma of the mandibular condyle with a piezoelectric surgical device

Background: Osteochondromas of the mandibular condyle show facial asymmetry and malocclusion. Because condylar osteochondromas are generally resected in a preauricular approach with risks of facial nerve injury and visible scar, the authors report endoscopically assisted intraoral resection of osteochondroma of the mandibular condyle with a piezoelectric surgical device.Case presentation: A 38-year-old woman presented with malocclusion and facial asymmetry caused by deviation of the chin to the left. Computed tomography showed a hyperdense, well-circumscribed mass arising from the medial aspect of the right mandibular condyle with resorption of the skull base. The patient underwent an endoscopically-assisted intraoral condylectomy with a piezoelectric surgical device. The postoperative course was uneventful without trismus, malocclusion, or facial asymmetry, and there was no recurrence 4 years after surgery.Conclusion:Endoscopically assisted intraoral resection of osteochondroma of the mandibular condyle with a piezoelectric surgical device is a minimally invasive and safe surgery.

Multicenter retrospective study of nivolumab for recurrent/metastatic oral squamous cell carcinoma

OBJECTIVES

Immunotherapy with nivolumab for patients with recurrent/metastatic oral squamous cell carcinoma has not been evaluated. Here, we aimed to examine the efficacy, safety, and prognostic factors of nivolumab in these patients.

MATERIALS AND METHODS

This multicenter retrospective observational study involved patients who received nivolumab between April 2017 and June 2019. The patient characteristics were evaluated for association with progression-free and overall survival. Progression-free and overall survival rates were calculated; parameters that were significant in the univariate analysis were used as explanatory variables. Independent factors for progression-free and overall survival were identified using multivariate analysis.

RESULTS

Totally, 143 patients were included. The overall response and disease control rates were 27.3% and 46.2%, respectively. The median, 1- and 2-year progression-free survival rates were 2.7 months, 25.4%, and 19.2%, respectively; those for overall survival were 11.2 months, 47.3%, and 33.6%, respectively. The independent factors affecting progression-free survival were performance status and immune-related adverse event occurrence, whereas those affecting overall survival were performance status, target disease, and number of previous lines of systemic cancer therapy. Eight patients reported grade ≥3 immune-related adverse events.

CONCLUSION

Nivolumab was effective for recurrent/metastatic oral squamous cell carcinoma treatment and was well tolerated by patients.

Diameters of lingual, facial, and maxillary arteries measured according to an objective protocol on 3D computed tomography angiography images

PURPOSE

Retrograde superselective intra-arterial chemoradiotherapy is a radical treatment for advanced oral cancer. The catheter tip is placed into tumor-feeding arteries-the lingual, facial, or maxillary arteries. The diameter of the tumor-feeding arteries newly bifurcated from the external carotid artery is crucial for determining the requirement of a catheter navigation system. This study aimed to measure the diameter and distribution of the tumor-feeding artery according to an objective protocol using 3D computed tomography angiography images reproducibly.

METHODS

Angiographic data of 20 noncatheterized carotid arteriesof 10 randomly selected patients were analyzed. We followed the external carotid artery to the entrance of each feeding artery to determine the center point where the artery diameter was measured. The diameter of the optimum circle measured at the adopted center point was taken as the diameter of each tumor-feeding artery.

RESULTS

The diameters (mean ± standard deviation) were 3.5 ± 0.45, 2.9 ± 0.56, and 3.5 ± 0.56 mm for the maxillary, lingual, and facial arteries, respectively. The diameters of the maxillary and facial arteries were similar (p = 0.877), whereas the diameter of the lingual artery was smaller than that of the maxillary and facial arteries (p < 0.001).

CONCLUSION

The findings of this study will be beneficial in determining the need of a new catheter navigation system and diameter of catheters to be used in the clinical practice. From the viewpoint of measurement automation and reproducibility, 3DCTA vessel measurement taken according to the proposed protocol was considered to be effective.

Accuracy and influencing factors of maxillary and mandibular repositioning using pre-bent locking plates: a prospective study

In-house repositioning methods based on three-dimensional (3D)-printing technology and the use of pre-bent plates has been gaining popularity in orthognathic surgery. However, there remains room for further improvement in methods and investigations on clinical factors that affect accuracy. This single-centre, prospective study included 34 patients and aimed to evaluate the accuracy and factors influencing maxillary and mandibular repositioning using pre-bent locking plates. The plates were manually pre-bent on the 3D-printed models of the planned position, and their hole positions were scanned and reproduced intraoperatively with osteotomy guides. The accuracy of repositioning and plate-hole positioning was calculated in three axes with the set landmarks. The following clinical factors that affect repositioning accuracy were also verified: deviation of the plate-hole positioning, amount of planned movement, and amount of simulated bony interference. The median deviations of the repositioning and hole positioning between the preoperative plan and postoperative results were 0.26 mm and 0.23 mm, respectively, in the maxilla, and 0.69 mm and 0.36 mm, respectively, in the mandible, suggesting that the method was highly accurate, and the repositioning concept based on the plate hole and form matching was more effective in the maxilla. Results of the correlation test suggest that large amounts of bony interference and plate-hole positioning errors in the up/down direction could reduce mandibular repositioning accuracy.

Synergistic Enhancement of Protein Recruitment and Retention via Implant Surface Microtopography and Superhydrophilicity in a Computational Fluid Dynamics Model

The exact mechanisms by which implant surface properties govern osseointegration are incompletely understood. To gain insights into this process, we examined alterations in protein and blood recruitment around screw implants with different surface topographies and wettability using a computational fluid dynamics (CFD) model. Compared with a smooth surface, a microrough implant surface reduced protein infiltration from the outer zone to the implant thread and interface zones by over two-fold. However, the microrough implant surface slowed blood flow in the interface zone by four-fold. As a result, compared with the smooth surface, the microrough surface doubled the protein recruitment/retention index, defined as the mass of proteins present in the area per unit time. Converting implant surfaces from hydrophobic to superhydrophilic increased the mass of protein infiltration 2-3 times and slowed down blood flow by up to two-fold in the implant vicinity for both smooth and microrough surfaces. The protein recruitment/retention index was highest at the implant interface when the implant surface was superhydrophilic and microrough. Thus, this study demonstrates distinct control of the mass and speed of protein and blood flow through implant surface topography, wettability, and their combination, significantly altering the efficiency of protein recruitment. Although microrough surfaces showed both positive and negative impacts on protein recruitment over smooth surfaces, superhydrophilicity was consistently positive regardless of surface topography.

Optimization of blood and protein flow around superhydrophilic implant surfaces by promoting contact hemodynamics

PURPOSE

We examined blood and protein dynamics potentially influenced by implant threads and hydrophilic/hydrophobic states of implant surfaces.

METHODS

A computational fluid dynamics model was created for a screw-shaped implant with a water contact angle of 70° (hydrophobic surface) and 0° (superhydrophilic surface). Movements and density of blood and fibrinogen as a representative wound healing protein were visualized and quantified during constant blood inflow.

RESULTS

Blood plasma did not occupy 40-50% of the implant interface or the inside of threads around hydrophobic implants, whereas such blood voids were nearly completely eliminated around superhydrophilic implants. Whole blood field vectors were disorganized and random within hydrophobic threads but formed vortex nodes surrounded by stable blood streams along the superhydrophilic implant surface. The averaged vector within threads was away from the implant surface for the hydrophobic implant and towards the implant surface for the superhydrophilic implant. Rapid and massive whole blood influx into the thread zone was only seen for the superhydrophilic implant, whereas a line of conflicting vectors formed at the entrance of the thread area of the hydrophobic implant to prevent blood influx. The fibrinogen density was up to 20-times greater at the superhydrophilic implant interface than the hydrophobic one. Fibrinogen density was higher at the interface than outside the threads only for the superhydrophilic implant.

CONCLUSIONS

Implant threads and surface hydrophilicity have profound effects on vector and distribution of blood and proteins. Critically, implant threads formed significant biological voids at the interface that were negated by superhydrophilicity-induced contact hemodynamics.

A Novel Orthognathic Surgery With a Half-Millimeter Accuracy for the Maxillary Positioning Using Prebent Plates and Computer-Aided Design and Manufacturing Osteotomy Guide

This retrospective study aimed to assess the accuracy of prebent plates and computer-aided design and manufacturing osteotomy guide for orthognathic surgery. The prebent plates correspondent to the planning model were scanned with a 3-dimensional printed model for guide design and used for fixation. Forty-two patients who underwent bimaxillary orthognathic surgery using computer-aided design and manufacturing intermediate splint with the guide (guided group: 20 patients) or with conventional fixation under straight locking miniplates (SLMs) technique (SLM group: 20 patients) were analyzed. A deviation of the maxilla between the planned and postoperative positions was evaluated using computed tomography, which was taken 2 weeks before and 4 days after the surgery. The surgery time and the infraorbital nerve paranesthesia were also evaluated. The mean deviations in the mediolateral ( x ), anteroposterior ( y ), and vertical directions ( z ) were 0.25, 0.50, and 0.37 mm, respectively, in the guided group, while that in the SLM group were 0.57, 0.52, and 0.82 mm, respectively. There were significant differences in x and z coordinates ( P <0.001). No significant difference in the surgery duration and paranesthesia was seen, suggesting the present method offers a half-millimeter accuracy for the maxillary repositioning without increasing the risk of extending surgery duration and nerve complication.

Influence of the Oral Health Assessment Tool Score on Survival of Patients With Esophageal Cancer

BACKGROUND/AIM

We investigated the influence of the preoperative Oral Health Assessment Tool (OHAT) score on the outcomes of patients with esophageal cancer after curative surgery.

PATIENTS AND METHODS

This study included 90 patients with esophageal cancer who underwent curative surgery and who were screened with the OHAT between 2008 and 2021. The OHAT consists of eight categories with three possible scores. The risk factors for 5-year overall survival (OS) and recurrence-free survival (RFS) were identified.

RESULTS

Patients were divided into healthy (n=42) and unhealthy (n=48) groups. The OHAT score was identified as a significant risk factor for postoperative pneumonia (11.9% vs. 43.8%, p=0.001) and postoperative hospital stay (20.5 days vs. 50.1 days, p=0.042). The 5-year OS rate after surgery was 71.2% in the healthy group and 43.2% in the unhealthy group, which was a significant difference (p=0.015). A multivariate analysis showed that a high OHAT score was a significant independent factor for 5-year OS (p=0.034).

CONCLUSION

The OHAT score was a useful prognostic marker in patients who underwent curative surgery for esophageal cancer. To improve the oncological outcomes of patients with esophageal cancer, it is necessary to carefully plan perioperative oral/dental care using the OHAT score.

Transcriptome of Oral Cancer Cells Adapted to Suspension Culture Is Potentially Related to Cancer Progressive Phenotypes

BACKGROUND/AIM

Cervical lymph node metastasis worsens oral cancer prognosis. Cancer cells with high metastatic ability can delay or resist apoptosis and survive in the floating condition during circulation. The involved genes and pathways in this process remain largely unknown. This study aimed to establish an oral cancer cell line adapted to suspension culture by in vitro selection and perform gene expression analysis.

MATERIALS AND METHODS

The oral cancer cell subline adapted to suspension culture was isolated by in vitro selection from the oral cancer cell line, HSC-3. The transcriptome profiles of HSC-3 and its subline were compared using gene expression microarrays. Gene Ontology (GO) enrichment analysis, Gene Set Enrichment Analysis (GSEA), and Ingenuity Pathway Analysis (IPA) were performed to predict the involved pathways and molecules in cancer progression.

RESULTS

The subline was designated as HSC-3S5 The cellular viability of HSC-3S5 cells at the suspension culture was higher than that of HSC-3 cells. A total of 961 genes were differentially expressed between HSC-3 and HSC-3S5 cells under the threshold cut-off (FDR-adjusted p-value of <0.05 and absolute fold change of >1.5). GO terms, such as growth regulation, were enriched in the DEGs. GSEA revealed the association between the DEGs and significant gene sets, including metastasis and stemness. IPA predicted that the proliferation-related pathways were enhanced while the apoptotic pathway was inhibited in HSC-3S5 cells compared to HSC-3 cells.

CONCLUSION

Our transcriptome analysis revealed several potentially activated pathways and molecules in the floating-adapted oral cancer cells and indicated molecular implications for cancer progression.

The Effects of a Biomimetic Hybrid Meso- and Nano-Scale Surface Topography on Blood and Protein Recruitment in a Computational Fluid Dynamics Implant Model

The mechanisms underlying bone-implant integration, or osseointegration, are still incompletely understood, in particular how blood and proteins are recruited to implant surfaces. The objective of this study was to visualize and quantify the flow of blood and the model protein fibrinogen using a computational fluid dynamics (CFD) implant model. Implants with screws were designed with three different surface topographies: (1) amorphous, (2) nano-trabecular, and (3) hybrid meso-spikes and nano-trabeculae. The implant with nano-topography recruited more blood and fibrinogen to the implant interface than the amorphous implant. Implants with hybrid topography further increased recruitment, with particularly efficient recruitment from the thread area to the interface. Blood movement significantly slowed at the implant interface compared with the thread area for all implants. The blood velocity at the interface was 3- and 4-fold lower for the hybrid topography compared with the nano-topography and amorphous surfaces, respectively. Thus, this study for the first time provides insights into how different implant surfaces regulate blood dynamics and the potential advantages of surface texturization in blood and protein recruitment and retention. In particular, co-texturization with a hybrid meso- and nano-topography created the most favorable microenvironment. The established CFD model is simple, low-cost, and expected to be useful for a wide range of studies designing and optimizing implants at the macro and micro levels.

Potentiation of Anticancer Activity of G2/M Blockers by Mild Hyperthermia

BACKGROUND/AIM

Hyperthermia (HT), combined with chemotherapy, has been used to treat various types of cancer. This study aimed to investigate the HT-sensitivity of malignant and non-malignant cells, and then evaluate the combination effect of docetaxel (DTX) and a newly synthesized chromone derivative (compound A) with HT.

MATERIALS AND METHODS

The number of viable cells was determined using the MTT method. Cell cycle distribution was analyzed using a cell sorter, and DNA fragmentation pattern was detected using agarose gel electrophoresis.

RESULTS

Among 12 cultured cells, oral squamous cell carcinoma (OSCC), especially Ca9-22 cells, and myelogenous leukemia cells showed higher sensitivity to HT than lung carcinoma and glioblastoma cell lines, while normal oral cells were the most resistant. Cytotoxicity of DTX on Ca9-22 cells was maximum at 41-42°C and 45~60 min exposure to HT. DXT, compound A, and HT induced G2/M arrest of Ca-22 cells. Mild HT enhanced the DTX- and compound A-induced subG1 arrest, in a synergistic fashion.

CONCLUSION

The combination G2/M blockers and mild-HT can potentially be used for the treatment of OSCC.

Efficacy of concurrent chemoradiotherapy with retrograde super selective intra-arterial infusion combined with cetuximab for synchronous multifocal oral squamous cell carcinomas

BACKGROUND

The incidence of multicentric oral cancer is increasing. However, treatment encounters difficulty if each tumor needs to be treated simultaneously. The objective of this clinical case report is to highlight the effect of concurrent chemoradiotherapy with retrograde superselective intra-arterial infusion combined with systemic administration of cetuximab on synchronous multifocal oral squamous cell carcinomas.

CASE PRESENTATION

A 70-year-old man presented to the hospital with multiple tumors and oral pain. Three independent tumors were found in the right dorsal tongue, left edge of the tongue, and left lower lip. Based on the characteristic appearance of the lesions and further evaluation, clinical diagnoses of right tongue cancer "T3", left tongue cancer "T2" and lower left lip cancer "T1", N2cM0 were made. Treatment was initiated with systemic administration of cetuximab, followed by intra-arterial chemoradiotherapy. Treatment results were complete response on all three local lesions, and left neck dissection was performed following the initial treatment. The patient showed no evidence of recurrence during the 4 years follow-up period.

CONCLUSIONS

This novel combination treatment seems to be a promising strategy for patients with synchronous multifocal oral squamous cell carcinoma.

Abstract 4835: EP4 increases the mitochondrial respiration and promotes cell migration in oral cancer

Introduction: EP4 is one of the prostaglandin E2 (PGE2) receptors. We previously reported that EP4 promoted cell migration via Ca2+ signaling, however the underlying mechanism has remained unclear. In Ca2+ signaling, Store-operated Ca2+entry (SOCE) is a major mechanism of Ca2+ import from the extracellular to the intracellular space. Orai1, one of the selective Ca2+ channels, plays an important role in SOCE. We focused on the correlation with EP4 and Orai1. Additionally, we found that EP4 promoted the phosphorylation of calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) and AMP-activated protein kinase (AMPK) located downstream of CaMKK2, i.e., cell energy regulators. AMPK activation can control positively or negatively the cellular adenosine triphosphate (ATP) supply. Therefore, we investigated how EP4 regulated the mitochondrial function via Ca2+ and promoted the cell migration in oral cancer cells.

Materials and Methods: HSC-3, human tongue squamous cell carcinoma cell line was used. ONO-AE1-437 was used as EP4 agonist. HSC-3 cells were transduced with Orai1 shRNA, and control shRNA using lentivirus. The migration ability was evaluated by scratch assay. Measurement of intracellular Ca2+ concentration was measured using Fura-2. Immunoprecipitation was performed to evaluate the interaction between EP4 and Orai1. XF Cell Mito Stress Test and XF Real-Time ATP Rate Assay were performed to evaluate the mitochondrial aspiration and the ATP production using Extracellular Flux Analyzer.

Results: Scratch assay showed EP4 promoted cell migration in oral cancer cells (n=4, p&lt;0.05). In contrast, Orai1 knockdown negated EP4-induced cell migration. EP4 rapidly increased the intracellular Ca2+ concentration, while Orai1 knockdown negated EP4-indued Ca2+ increase (n=4, p&lt;0.05). Immunoprecipitation showed that EP4 was colocalized and formed complexes with Orai1 (n=4, p&lt;0.05). These results indicated that EP4 promoted the cell migration via Ca2+ signaling through Orai1. EP4 increased the maximal respiration 3h after the stimulation (n=6, p&lt;0.05). ATP production rate shifted mitoATP dominant. These data indicated that EP4 increased the mitochondrial function and the respiratory capacity, potentially regulating its energy supply. These results demonstrated that EP4 promoted mitochondria respiration and then increased the energy production from mitochondria in oral cancer cells.

Conclusion: We concluded that EP4 regulated the mitochondrial function via Ca2+ through Orai1 and promoted the cell migration in oral cancer cells.

Citation Format: Rina Nakakaji, Masanari Umemura, Kohei Osawa, Soichiro Ishikawa, Kenji Mitsudo, Yoshihiro Ishikawa. EP4 increases the mitochondrial respiration and promotes cell migration in oral cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4835.

Abstract 3619: EP4 promoted cell migration via mitochondrial biogenesis in oral cancer cells

Introduction: Lymph node metastasis caused by migration of oral cancer cells is an important prognostic factor. We previously reported that EP4, a prostaglandin E2 (PGE2) receptor, regulates the cell migration in oral cancer cells via Ca2+ signaling. However, how Ca2+ signaling regulates cell migration remains unclear. The intracellular Ca2+ regulates a variety of signaling pathways, either directly or by forming complexes with proteins such as calmodulin (CaM), and then phosphorylates calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2). Furthermore, Ca2+ signaling is directly or indirectly involved in cancer cell proliferation and migration. Therefore, we hypothesized that EP4 regulates the cell migration via CaMKK2 and its downstream signaling in oral cancer.

Materials and Methods: Human gingival fibroblasts, HGnF and Human tongue squamous cell carcinoma cell lines, HSC-3 were used. EP4 agonist (ONO-AE1-437) and CaMKK2 inhibitor (STO-609) were used. HSC-3 cells were transduced with CaMKK2 shRNA, and scramble control shRNA using lentivirus. The protein expressions were evaluated by western blotting. The intracellular calcium concentrations were measured using Fura-2, the Fluorescent Ca2+ Indicator. The cell migration ability was evaluated by scratch assay. Immunocytochemistry was performed to evaluate the lamellipodium. The mRNA transcriptions of the mitochondrial associated genes were evaluated by real-time qPCR. The intracellular adenosine triphosphate (ATP) production and the reactive oxygen species (ROS) production were also evaluated by luciferase activity assay and DCFH-DA staining.

Results: EP4 protein expression of HSC-3 cells was higher than that of HGnF cells (n=4, p&lt;0.001). EP4 agonist rapidly increased the intracellular calcium in HSC-3 cells but not in HGnF cells (n=4, p&lt;0.001). EP4 agonist also promoted the cell migration and increased the lamellipodia formation in HSC-3 cells (n=3, p&lt;0.001). Furthermore, EP4 agonist promoted the phosphorylation of CaMKK2 and AMP-activated protein kinase (AMPK) (n=4, p&lt;0.001). In contrast, CaMKK2 inhibitor and CaMKK2 knockdown suppressed EP4-stimulated cell migration and AMPK phosphorylation (n=4, p&lt;0.001). Furthermore, EP4 agonist increased the expression of the transcriptional coactivator PGC1-α, mtDNA and mitochondrial transcription factor A (TFAM) (n=4, p&lt;0.01). Furthermore, EP4 agonist increased the intracellular ATP production and the ROS production (n=6, p&lt;0.01). Taken together, EP4 regulated the mitochondrial biogenesis via CaMKK2 and AMPK, and promoted the cell migration in oral cancer.

Conclusion: EP4/CaMKK2/AMPK pathway is a novel signal transduction in oral cancer and may be a new target for oral cancer therapy.

Citation Format: Soichiro Ishikawa, Masanari Umemura, Rina Nakakaji, Akane Nagasako, Kagemichi Nagao, Yuto Mizuno, Fumina Suzuki, Kohei Osawa, Mitomu Kioi, Kenji Mitsudo, Yoshihiro Ishikawa. EP4 promoted cell migration via mitochondrial biogenesis in oral cancer cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3619.

Ultraviolet Light Treatment of Titanium Microfiber Scaffolds Enhances Osteoblast Recruitment and Osteoconductivity in a Vertical Bone Augmentation Model: 3D UV Photofunctionalization

Vertical bone augmentation to create host bone prior to implant placement is one of the most challenging regenerative procedures. The objective of this study is to evaluate the capacity of a UV-photofunctionalized titanium microfiber scaffold to recruit osteoblasts, generate intra-scaffold bone, and integrate with host bone in a vertical augmentation model with unidirectional, limited blood supply. Scaffolds were fabricated by molding and sintering grade 1 commercially pure titanium microfibers (20 μm diameter) and treated with UVC light (200-280 nm wavelength) emitted from a low-pressure mercury lamp for 20 min immediately before experiments. The scaffolds had an even and dense fiber network with 87% porosity and 20-50 mm inter-fiber distance. Surface carbon reduced from 30% on untreated scaffold to 10% after UV treatment, which corresponded to hydro-repellent to superhydrophilic conversion. Vertical infiltration testing revealed that UV-treated scaffolds absorbed 4-, 14-, and 15-times more blood, water, and glycerol than untreated scaffolds, respectively. In vitro, four-times more osteoblasts attached to UV-treated scaffolds than untreated scaffolds three hours after seeding. On day 2, there were 70% more osteoblasts on UV-treated scaffolds. Fluorescent microscopy visualized confluent osteoblasts on UV-treated microfibers two days after seeding but sparse and separated cells on untreated microfibers. Alkaline phosphatase activity and osteocalcin gene expression were significantly greater in osteoblasts grown on UV-treated microfiber scaffolds. In an in vivo model of vertical augmentation on rat femoral cortical bone, the interfacial strength between innate cortical bone and UV-treated microfiber scaffold after two weeks of healing was double that observed between bone and untreated scaffold. Morphological and chemical analysis confirmed seamless integration of the innate cortical and regenerated bone within microfiber networks for UV-treated scaffolds. These results indicate synergy between titanium microfiber scaffolds and UV photofunctionalization to provide a novel and effective strategy for vertical bone augmentation.

The Expression of SIRT6 Is Associated With Treatment Outcome in Elder Patients With Oral Cancer

BACKGROUND/AIM

SIRT6 is one of seven human sirtuin genes and is known to act as an onco-suppressor gene in colorectal and ovarian cancers, although it is up-regulated in other cancers. Thus, SIRT6 is considered performing both tumor-suppressing and promoting roles. However, the association of SIRT6 with oral squamous cell carcinoma (OSCC) and its role in OSCC pathogenesis is currently unclear. This study aimed to investigate the expression of SIRT6 in patients with OSCC and its potential as a biomarker for early detection and prognosis prediction.

MATERIALS AND METHODS

Immunohistochemistry, quantitative real-time RT-PCR, and microarray analyses were performed to determine SIRT6 expression and its association with clinicopathological features in OSCC using clinical specimens.

RESULTS

SIRT6 mRNA and protein expression levels were higher in OSCC tissues than in noncancerous tissues (p<0.05). SIRT6 expression was predominant in patients aged ≥65 years and significantly correlated with shorter overall survival. In the microarray analysis, some SIRT6-associated genes, such as ANXA2, were up-regulated in OSCC.

CONCLUSION

SIRT6 plays a role in tumor homeostasis, leading to a poor prognosis in OSCC. SIRT6 may represent a novel target not only for treatment, but also as a prognostic marker in OSCC.

Sentinel lymph node biopsy with a handheld cordless magnetic probe following preoperative MR lymphography using superparamagnetic iron oxide for clinically N0 early oral cancer: A feasibility study

PURPOSE

Radioisotope (RI) tracers are generally used for preoperative mapping of sentinel lymph node (SLN) and intraoperative detection with a portable γ probe. However, the use of RI has several limitations. Therefore, a method without RI is required for the widespread application of SLN biopsy. The purpose of this study was to evaluate the feasibility of SLN biopsy with a handheld cordless magnetic probe following magnetic resonance lymphography (MRL) using superparamagnetic iron oxide (SPIO) and for clinically N0 early oral cancer.

MATERIALS AND METHODS

MRL using SPIO and SLNB with the handheld cordless magnetic probe were performed for 27 patients with clinically N0 early oral cancer.

RESULTS

In all 27 patients (100%), SLNs were detected by MRL, and the total and mean number of SLNs were 73 and 2.7, respectively. All SLNs identified by MRL were detectable using the magnetic probe in all patients.

CONCLUSIONS

SLNB with handheld cordless magnetic probe following preoperative SLN mapping by MRL using SPIO is feasible, without RI use, for neck management in cases of clinically N0 early oral cancer.

Oral candidiasis caused by ciclesonide in a patient with COVID-19 pneumonia: A case report and literature review

Steroid has recently been reported as a treatment for new coronavirus disease (COVID-19). The incidence of oropharyngeal candidiasis due to the inhaled steroid ciclesonide is lower than that due to other inhaled steroids. We report the first case of oral candidiasis with COVID-19 pneumonia using ciclesonide. A 75-year-old man was hospitalized for COVID-19 pneumonia. After admission, an oral combination of lopinavir/ritonavir was administered, and ciclesonide was inhaled for 7 days. On the 14th day of hospitalization, white plaque was found in his oral mucosa. Candida albicans was identified by oral bacterial tests, and amphotericin B was initiated. On the 35th hospital day, negative result for C. albicans was confirmed. Intraoral monitoring and intervention by dental care workers are considered important for the prevention of infectious complications induced by corticosteroids.

A simple method with a sterilized surgical glove for removal of stripped screw

In oral and maxillofacial surgery such as orthognathic surgery and open treatment of maxillofacial fracture, plate fixation is commonly performed. Although the removal of titanium miniplates is controversial, the plates are removed routinely or symptomatically. By excessive torque during the screw removal, stripping or breaking of screw heads may occur. Although miniplates and screws are used with angled screwdrivers for osteosynthesis in bilateral sagittal split osteotomy (BSSO) or open treatment of mandibular angle or subcondylar fracture, the removal of a damaged screw, especially with the angled screwdriver, is very difficult. Therefore, we report a simple method with a sterilized surgical glove for removal of the stripped screw.

Transcriptomic Profiling Predicts Multiple Pathways and Molecules Associated With the Metastatic Phenotype of Oral Cancer Cells

BACKGROUND/AIM

Metastasis to cervical lymph nodes of oral squamous cell carcinoma (OSCC) leads to a poor prognosis. The present study aimed at investigating the pathways and molecules associated with OSCC metastasis.

MATERIALS AND METHODS

The transcriptome between HSC-3 cells and their highly metastatic subline, HSC-3-M3 cells, was examined using gene expression microarray. Gene enrichment analyses and Ingenuity Pathway Analysis were performed. Kaplan-Meier plot analysis using a publicly available dataset was conducted to assess whether candidate molecules are prognosticators.

RESULTS

A total of 1,018 genes were differentially expressed, and the inflammatory pathway and NF-kB were predicted to be activated in HSC-3-M3 cells. CSF2 was suggested to be an indicator of poor prognosis in head and neck cancers.

CONCLUSION

Inflammation and NF-kB may be involved in the metastasis of OSCC, and CSF2 is a promising diagnostic and therapeutic molecule. Moreover, HSC-3-M3 cells are a useful cell line model for studying OSCC progression.

MR lymphography with superparamagnetic iron oxide for sentinel lymph node mapping of N0 early oral cancer: A pilot study

OBJECTIVES

The purpose of this pilot study was to evaluate the usefulness of magnetic resonance lymphography (MRL) with superparamagnetic iron oxide (SPIO) in sentinel lymph node (SLN) mapping of clinically N0 early oral cancer, and to conduct a comparative study of this MRL with CT lymphography (CTL).

METHODS

CTL and MRL were performed for SLN mapping before surgery for 20 patients with clinically N0 early oral cancer. The detection rate, number, and location of SLNs in CTL and MRL were evaluated. Furthermore, optimal scanning/imaging timing in MRL was examined.

RESULTS

SLNs were detected by CTL in 18 (90%) patients, and the total and mean number of SLN were 35 and 1.8, respectively. All SLNs could be detected 2 min and 3.5-5 min after contrast medium injection. In all patients, SLNs were detected by MRL at 10 min after SPIO injection, and the total and mean number of SLN was 53 and 2.7, respectively. MRL at 30 min after the injection showed additional 18 secondary lymph nodes.

CONCLUSION

MRL with SPIO is safe and useful imaging for the detection of SLNs in clinically N0 early oral cancer, and the optimal imaging timing is 10 min after SPIO injection.

A three-dimensional finite element analysis of resected mandibular bone to determine the most stable implant positions for a fixed prosthesis

This study was conducted to determine the most secure implant positioning on the marginally resected mandible to support a fixed complete denture through finite element analysis. Three or four implants were placed at near, middle, or far positions from the resected margin in a simulation model with a symmetrical marginal defect in the mandibular symphysis. The height of the residual bone was 5, 10, or 15 mm. The four possible implant patterns for 3 or 4 implants were defined as: (1) asymmetrically isolated position one to position two, (2) asymmetrically isolated position one to position three, (3) asymmetrically isolated with greater length position one to position two, and (4) two implants symmetrically positioned on each side of the defect. The von Mises stress in the resected and peri-implant bone with respect to the occlusal force was calculated. Initially, as the peri-implant bone stress around isolated implant at the near position was greater than at the middle and far positions regardless of the residual bone height, the near position was excluded. Second, the von Mises stress in the resected bone region was > 10 MPa when the isolated implant was at the far position, and it increased inversely depending on the bone height. However, the stress was < 10 MPa when the isolated implant was placed at the middle position regardless of the bone height, and it was significantly lower compared to the far position, and equivalent to the symmetrically positioned implants. Furthermore, the use of greater length implant reduced the peri-implant bone stress, which was even lower than that of the symmetrically positioned implants. These results suggest that the asymmetrically positioned three-implant-supported fixed denture, using a greater length isolated implant, placed neither too close to nor too far from the resected margin, can be an effective alternative to the symmetrically positioned four-implant-supported fixed denture.

Hypoxia and CD11b+ Cell Influx Are Strongly Associated With Lymph Node Metastasis of Oral Cancer

BACKGROUND/AIM

Treatment failure in oral cancer is mainly caused by uncontrolled cervical lymph node (LN) metastasis. We previously reported that CD11b+ cells are recruited into tumor hypoxic areas following radiation, leading to re-vascularization and relapse. Since lymphatic vessel formation has similarities with vascular formation, we examined whether surgery induces hypoxia and stimulates lymphangiogenesis.

MATERIALS AND METHODS

The recruitment of CD11b+ cells and the formation of lymphatic vessels were examined using orthotopic tongue cancer mouse models with glossectomy.

RESULTS

Surgery on OSC-19 tumor induced LN metastases and hypoxia, followed by CD11b+ cell influx. These phenomena were not observed in the no tumor or SAT tumor models. Stimulation of lymphangiogenesis was observed in the CD11b+ cell influx area, as the tumor grew. The localization of CD11b+ cells was changed from the lymph nodules to the medullary sinuses.

CONCLUSION

Surgery-induced hypoxia in oral tumors leads to CD11b+ cell infiltration, lymphangiogenesis, and LN metastasis.

Impact of superselective intra-arterial and systemic chemoradiotherapy for gingival carcinoma; analysis of treatment outcomes and prognostic factors

Background

We compared outcomes and toxicities between concurrent retrograde super-selective intra-arterial chemoradiotherapy (IACRT) and concurrent systemic chemoradiotherapy (SCRT) for gingival carcinoma (GC).

Methods

We included 84 consecutive patients who were treated for non-metastatic GC ≥ stage III, from 2006 to 2018, in this retrospective analysis (IACRT group: n = 66; SCRT group: n = 18).

Results

The median follow-up time was 24 (range: 1–124) months. The median prescribed dose was 60 (6–70.2) Gy (IACRT: 60 Gy; SCRT: 69 Gy). There were significant differences between the two groups in terms of 3-year overall survival (OS; IACRT: 78.8, 95% confidence interval [CI]: 66.0–87.6; SCRT: 50.4, 95% CI: 27.6–73.0; P = 0.039), progression-free survival (PFS; IACRT: 75.6, 95% CI: 62.7–85.2; SCRT: 42.0, 95% CI: 17.7–70.9; P = 0.028) and local control rates (LC; IACRT: 77.2, 95% CI: 64.2–86.4; SCRT: 42.0, 95% CI: 17.7–70.9; P = 0.015). In univariate analysis, age ≥ 65 years, decreased performance status (PS) and SCRT were significantly associated with worse outcomes (P < 0.05). In multivariate analysis, age ≥ 65 years, clinical stage IV, and SCRT were significantly correlated with a poor OS rate (P < 0.05). Patients with poorer PS had a significantly worse PFS rate. Regarding acute toxicity, 22 IACRT patients had grade 4 lymphopenia, and osteoradionecrosis was the most common late toxicity in both groups.

Conclusions

This is the first report to compare outcomes from IACRT and SCRT among patients with GC. ALL therapy related toxicities were manageable. IACRT is an effective and safe treatment for GC.

UV-Mediated Photofunctionalization of Dental Implant: A Seven-Year Results of a Prospective Study

Our objective was to evaluate the seven-year results of photofunctionalized implants placed in regular, complex, and cancer-related cases. This study was a prospective, single-center study. Photofunctionalization was performed immediately prior to implantation with Ultraviolet (UV) light for 15 minutes. The success rate of each patient group and the influential factors on implant failure were analyzed. Seventy implants in 16 patients were included. Four implants were left submerged (sleep). The seven-year success rate of 30 implants in regular cases and 21 implants in complex cases was 100%. The success rate of 15 implants in cancer-related cases was 22.2%, in which implants were placed in resection or reconstructed sites with or without pre- or postoperative radiation history. Implant stability quotient (ISQ) values increased at second-stage surgery by 3.2 in regular cases and by 21.9 in complex cases, while it decreased by −3.5 in cancer cases. Multivariate analysis indicated that bone quality, location, and cancer resection significantly influenced implant failure. A very reliable seven-year success rate was obtained by UV-photofunctionalized implants in regular and complex cases, even with significant site-development procedures. However, the success rate in cancer cases was significantly and remarkably lower, suggesting remaining challenges of pathophysiologically compromised conditions, such as bone resection, segmental defect, and radiation.

Proton beam therapy combined with retrograde intra-arterial infusion chemotherapy for an extremely rapid growing recurrent ameloblastic carcinoma: A case report

Ameloblastic carcinoma (AC) is a very rare malignant odontogenic tumor. Although surgical resection is generally performed, treatment approaches have not been established for recurrent cases. Chemotherapy and radiotherapy are positioned as adjunctive therapies, and few studies investigated definitive non-operative therapy. We present the case of a 71-year-old male with recurrent secondary-type AC arising from the right maxilla, who was treated with proton beam therapy (PBT; 71.4 Gy relative biological effectiveness in 32 fractions) combined with continuous intra-arterial infusion of cisplatin (40 mg/m²) and docetaxel (8 mg/m²). The patient experienced acute grade 3 mucositis, dermatitis and neutropenia, which were resolved within 3 months of treatment. Late adverse events were grade 1 skin atrophy, and grade 2 right optic nerve disorder and retinopathy. After ~8 years of treatment, the patient died from another cause but did not experience any relapse or metastasis during the follow-up period of 94 months. To the best of our knowledge, this is the first report of recurrent AC treated with PBT and intra-arterial infusion chemotherapy without any severe late adverse events. This combination therapy approach may be considered as an effective therapeutic option for inoperable AC.