SCGB1A1 as a novel biomarker and promising therapeutic target for the management of HNSCC.

Head and neck cancer (HNC) is the sixth most common type of cancer worldwide, and head and neck squamous cell carcinoma (HNSCC) accounts for 90% of HNC cases. Furthermore, HNSCC accounts for 400,000 cancer-associated deaths worldwide each year. However, at present there is an absence of a versatile biomarker that can be used for diagnosis, prognosis evaluation and as a therapeutic target for HNSCC. In the present study, bioinformatics analysis was used to assess the relationship between hub genes and the clinical features of patients with HNSCC. The findings from the bioinformatics analysis were then verified using clinical samples and in vitro experiments. A total of 51 overlapping genes were identified from the intersection of differentially expressed genes and co-expressed genes. The top 10 hub genes were obtained from a protein-protein interaction network of overlapping genes. Among the hub genes, only secretoglobin family 1A member 1 (SCGB1A1) was significantly associated with both overall and disease-free survival. Specifically, upregulated SCGB1A1 expression levels were associated with prolonged overall and disease-free survival. Moreover, the SCGB1A1 expression levels were negatively correlated with drug sensitivity. Notably, it was demonstrated that SCGB1A1 was involved in tumor immunoreaction by affecting the infiltration of cells and checkpoint regulation of immune cells. Additionally, it was shown that SCGB1A1 regulated multiple key cancer-related signaling pathways, including extracellular matrix receptor interaction, transforming growth factor-ß and tumor metabolism signaling pathways. Based on the results of the present study, SCGB1A1 may serve as a novel biomarker for predicting the diagnosis, prognosis and therapeutic effectiveness of certain drugs in patients with HNSCC. Moreover, SCGB1A1 may serve as a potential therapeutic target for the management of HNSCC.

Injectable dual drug-loaded thermosensitive liposome-hydrogel composite scaffold for vascularised and innervated bone regeneration.

Adequate blood supply and thorough innervation are essential to the survival of tissue-engineered bones. Though great progress has been created in the application of bone tissue engineering technology to bone defect repair, many challenges remain, such as insufficient vascularisation and deficient innervation in newly regenerated bone. In the present study, we addressed these challenges by manipulating the bone regeneration microenvironment in terms of vascularisation and innervation. We used a novel injectable thermosensitive liposome-hydrogel composite scaffold as a sustained-release carrier for basic fibroblast growth factor (bFGF, which promotes angiogenesis and neurogenic differentiation) and dexamethasone (Dex, which promotes osteogenic differentiation). In vitro biological assessment demonstrated that the composite scaffold had sufficient cell compatibility; it enhanced the capacity for angiogenesis in human umbilical vein endothelial cells, and the capacity for neurogenic/osteogenic differentiation in human bone marrow mesenchymal stem cells. Moreover, the introduction of bFGF/Dex liposome-hydrogel composite scaffold to bone defect sites significantly improved vascularisation and innervated bone regeneration properties in a rabbit cranial defect model. Based on our findings, the regeneration of sufficiently vascularised and innervated bone tissue through a sustained-release scaffold with excellent injectability and body temperature sensitivity represents a promising tactic towards bone defect repair.

Biological characterization and complete genome analysis of the newly isolated Serratia liquefaciens phage vB_SlqS_ZDD2.

A novel lytic phage named vB_SlqS_ZDD2 was isolated from hospital sewage using the double-layer agar method with Serratia liquefaciens ATCC 27592 as the host. BLASTn analysis showed that the genome sequence of phage vB_SlqS_ZDD2 did not resemble any other phages in the NCBI database. Phenotype and phylogeny analysis indicated that this phage might be a new member of the class Caudoviricetes. Phage vB_SlqS_ZDD2 has a dsDNA genome of 49,178 bp with 55% GC content and has 73 open reading frames. This phage exhibited strong lytic activity and a wide range of pH (3-12) and temperature tolerance (below 70℃).

Leveraging genomic signatures of oral microbiome-associated antibiotic resistance genes for diagnosing pancreatic cancer.

Growing evidence has increasingly suggested a potential linkage between the oral microbiome and various diseases, including pancreatic ductal adenocarcinoma (PDAC). However, the utilization of gene-level information derived from the oral microbiome for diagnosing PDAC remains unexplored. In this study, we sought to investigate the novel potential of leveraging genomic signatures associated with antibiotic resistance genes (ARGs) within the oral microbiome for the diagnosis of PDAC. By conducting an analysis of oral microbiome samples obtained from PDAC patients, we successfully identified specific ARGs that displayed distinct sequence abundance profiles correlated with the presence of PDAC. In the healthy group, three ARGs were found to be enriched, whereas 21 ARGs were enriched in PDAC patients. Remarkably, these ARGs from oral microbiome exhibited promising diagnostic capabilities for PDAC (AUROC = 0.79), providing a non-invasive and early detection method. Our findings not only provide novel modal data for diagnosing PDAC but also shed light on the intricate interplay between the oral microbiome and PDAC.

Maxillary transverse deficiency diagnosed by 3 methods and its relationship with molar angulation in patients with skeletal Class III malocclusion.

INTRODUCTION: The objective of this study was to evaluate the relationship between maxillary transverse deficiency (MTD) diagnosed by 3 methods and molar angulation measured in 3-dimensions in patients with skeletal Class III malocclusion, which could give reference to the selection of diagnostic methods in MTD patients. METHODS: Cone-beam computed tomography data of 65 patients with skeletal Class III malocclusion (mean age 17.35 ± 4.45 years) were selected and imported into MIMICS software. Transverse deficiencies were evaluated by 3 methods, and molar angulations were measured after reconstructing 3-dimensional planes. Two examiners performed repeated measurements to assess the intraexaminer and interexaminer reliability. Pearson correlation coefficient analyses and linear regressions were performed to determine the relationship between a transverse deficiency and molar angulations. One-way analysis of variance was used to compare the diagnostic results of 3 methods. RESULTS: The novel molar angulation measurement method and 3 MTD diagnostic methods have the interexaminer and intraexaminer intraclass correlation coefficient values >0.6. The transverse deficiency diagnosed by 3 methods was significantly and positively correlated with the sum of molar angulation. There was a statistically significant difference for the transverse deficiencies diagnosed by the 3 methods. The transverse deficiency was significantly higher in Boston University's analysis than in Yonsei's analysis. CONCLUSIONS: Clinicians ought to choose the diagnostic methods properly, considering the feature of the 3 methods and the individual difference of each patient.

Microbial dysbiosis in oral squamous cell carcinoma: A systematic review and meta-analysis.

Objective: The aim of this study was to summarize previously published data and assess the alterations in the composition of the oral microbiome in OSCC using a systematic review and meta-analysis. Design: Electronic databases were systematically searched for studies on the oral microbiome in OSCC published before December 2021. Qualitative assessments of compositional variations at the phylum level were performed. The meta-analysis on abundance changes of bacteria genera was performed via a random-effects model. Results: A total of 18 studies involving 1056 participants were included. They consisted of two categories of studies: 1) case-control studies (n = 9); 2) nine studies that compared the oral microbiome between cancerous tissues and paired paracancerous tissues. At the phylum level, enrichment of Fusobacteria but depletion in Actinobacteria and Firmicutes in the oral microbiome was demonstrated in both categories of studies. At the genus level, Fusobacterium showed an increased abundance in OSCC patients (SMD = 0.65, 95% CI: 0.43-0.87, Z = 5.809, P = 0.000) and in cancerous tissues (SMD = 0.54, 95% CI: 0.36-0.72, Z = 5.785, P = 0.000). The abundance of Streptococcus was decreased in OSCC (SMD = -0.46, 95% CI: -0.88-0.04, Z = -2.146, P = 0.032) and in cancerous tissues (SMD = -0.45, 95% CI: -0.78-0.13, Z = -2.726, P = 0.006). Conclusions: Disturbances in the interactions between enriched Fusobacterium and depleted Streptococcus may participate in or prompt the occurrence and development of OSCC and could be potential biomarkers for detection of OSCC.

FOXM1 is regulated by DEPDC1 to facilitate development and metastasis of oral squamous cell carcinoma.

The Disheveled, EGL-10, Pleckstrin domain containing 1 (DEPDC1) is a new oncogene that has recently been described. The mechanisms and functions of its expression are yet to be determined in oral squamous cell carcinoma (OSCC). In the present study, the impact of DEPDC1 on the growth and development of OSCC was investigated using animal models, cell lines and human tissue samples. Elevated DEPDC1 expression within cancer cell lines and human OSCC has been identified. Mechanistic examination showed that restored DEPDC1 expression in vivo and in vitro stimulated OSCC tumour development. In addition, FOXM1 interacts with DEPDC1 as indicated by co-immunoprecipitation and immunofluorescence testing. Functionally, DEPDC1 facilitated Wnt/ß-catenin signal transduction and ß-catenin protein nuclear expression. In summary, the DEPDC1, interacting with FOXM1 via Wnt/ß-catenin signaling, the closely regulated OSCC pathogenesis, suggesting that targeting the novel DEPDC1/FOXM1/ß-catenin complex is an essential OSCC therapeutic approach.

Triple-functional injectable liposome-hydrogel composite enhances bacteriostasis and osteo/angio-genesis for advanced maxillary sinus floor augmentation.

Bone-grafting biological materials are commonly used to increase the height of the alveolar bone in the maxillary posterior region during maxillary sinus floor augmentation. However, there has been little research on the development of an injectable bone-grafting material with bacteriostatic, angiogenic, and osteogenic properties. In this work, we developed a triple-functional vancomycin/deferoxamine/dexamethasone (Van/DFO/Dex) liposome-hydrogel composite with desirable injectability. The release kinetics confirmed orderly sustained release of Van (a bacteriostat), DFO (a vascularised small molecule), and Dex (an osteogenic small molecule). In vitro findings demonstrated the favourable cytocompatibility and antibacterial ability of this composite against Staphylococcus aureus. Additionally, the angiogenic ability of human umbilical vein endothelial cells and osteogenic differentiation activity of MC3T3-E1 cells were enhanced. An in vivo bacteriostasis assay and rabbit maxillary sinus floor augmentation model corroborated the enhanced bacteriostasis and vascularised bone regeneration properties of this functionalised composite. Overall, the favourable injectability to be fit for the minimally invasive procedure, locally sustained release property, and prominent biological functions underscore the clinical potential of Van/DFO/Dex as an ideal bone-grafting material for irregular bone defect repairs, such as maxillary sinus floor augmentation.

Diagnostic and therapeutic role of microRNAs in oral cancer (Review).

Oral cancer is one of the leading types of cancer and remains the most common cause of cancer­related mortality in Asia. The pathogenesis of oral cancer is complicated and, due to lack of accurate diagnostic methods and efficient treatment strategies, oral cancer is responsible for a large number of deaths. Therefore, there is an urgent need for developing novel diagnostic tools and targeted therapies. MicroRNAs (miRNAs) represent a class of small non­coding RNAs that are key elements and play critical regulatory roles in the pathological processes of various diseases. miRNAs are widely distributed in body fluids and are specifically expressed in different cancers, and they may represent effective biomarkers that may be used for early detection of oral cancer. In addition, miRNAs are involved in oral cancer development, progression and prognosis by targeting a broad range of mRNAs that may be of therapeutic value for oral cancer. The aim of the present review was to summarize the role of miRNAs as new diagnostic tools and potential therapeutic targets in oral cancer, and investigate the underlying molecular mechanisms.

Signatures of Mucosal Microbiome in Oral Squamous Cell Carcinoma Identified Using a Random Forest Model.

OBJECTIVE: The aim of this study was to explore the signatures of oral microbiome associated with OSCC using a random forest (RF) model. PATIENTS AND METHODS: A total of 24 patients with OSCC were enrolled in the study. The oral microbiome was assessed in cancerous lesions and matched paracancerous tissues from each patient using 16S rRNA gene sequencing. Signatures of mucosal microbiome in OSCC were identified using a RF model. RESULTS: Significant differences were found between OSCC lesions and matched paracancerous tissues with respect to the microbial profile and composition. Linear discriminant analysis effect size analyses (LEfSe) identified 15 bacteria genera associated with cancerous lesions. Fusobacterium, Treponema, Streptococcus, Peptostreptococcus, Carnobacterium, Tannerella, Parvimonas and Filifactor were enriched. A classifier based on RF model identified a microbial signature comprising 12 bacteria, which was capable of distinguishing cancerous lesions and paracancerous tissues (AUC = 0.82). The network of the oral microbiome in cancerous lesions appeared to be simplified and fragmented. Functional analyses of oral microbiome showed altered functions in amino acid metabolism and increased capacity of glucose utilization in OSCC. CONCLUSION: The identified microbial signatures may potentially be used as a biomarker for predicting OSCC or for clinical assessment of oral cancer risk.

Quantitative Analysis of Salivary Oral Bacteria Associated with Severe Early Childhood Caries and Construction of Caries Assessment Model.

To construct a saliva-based caries risk assessment model, saliva samples from 176 severe early childhood caries (S-ECC) children and 178 healthy (H) children were screened by real-time PCR-based quantification of the selected species, including Streptococcus mutans, Prevotella pallens, Prevotella denticola and Lactobacillus fermentum. Host factors including caries status, dmft indices, age, gender, and geographic origin were assessed in their influence on abundance of the targeted species, which revealed host caries status as the dominant factor, followed by dmft indices (both P < 0.01). Moreover, levels of S. mutans and P. denticola in the S-ECC group were significantly higher than those in the healthy group (P < 0.001 for S. mutans and P < 0.01 for P. denticola). Interestingly, the co-occurrence network of these targeted species in the S-ECC group differed from that from the healthy group. Finally, based on the combined change pattern of S. mutans and P. pallens, we constructed an S-ECC diagnosis model with an accuracy of 72%. This saliva-based caries diagnosis model is of potential value for circumstances where sampling dental plague is difficult.

YY1-mediated PTEN dephosphorylation antagonizes IR-induced DNA repair contributing to tongue squamous cell carcinoma radiosensitization.

Ionizing radiation (IR) confers a survival advantage in tongue squamous cell carcinoma (TSCC), however, IR resistance limits its efficacy. Although Yin Yang 1 (YY1) has been reported to play a role in genotoxic drug resistance by accelerating DNA repair, its role in TSCC radioresistance remains unclear. In this study, we examined YY1 mRNA and protein expression in human tongue cancer samples using qRT-PCR and western blotting, respectively. DNA array data identified YY1 mRNA expression in IR sensitivity or resistance cell lines and tissues. Tongue carcinoma primary cells and CAL27 cells with YY1 stably overexpressed or knocked-down were exposed to IR and evaluated for cell proliferation and apoptosis by CCK8-assay and caspase-3 assay, respectively. We also examined DNA damage- or repair-related indicators, such as YY1, p-H2AX, nuclear PTEN, p-PTEN, and Rad51 through Western blot analysis. Additionally, we explored the mechanism of IR-induced PTEN nuclear translocation by introducing a series of PTEN phosphorylation site mutations and co-IP assay. We observed that YY1 mRNA and protein are highly expressed in TSCC tissues, which was correlated with worse overall survival. Moreover, higher expression of YY1 and Rad51 was observed in radioresistant cells and tissues, overexpression of YY1 led to IR resistance in TSCC cells, whereas YY1 knockdown sensitized TSCC cells to IR. The underlying mechanism showed that the overexpression of YY1 upregulated nuclear PTEN and Rad51 expression, which is essential for DNA repair. IR upregulated YY1, nuclear PTEN, and Rad51; thus, knockdown of YY1 completely blocked IR-induced upregulation of nuclear PTEN/Rad51. IR upregulated PTEN phosphorylation, and mutation of the phosphorylation site of Ser380 nearly completely blocked IR-induced PTEN nuclear translocation. Furthermore, the phosphatase PP2A negatively regulated pS380-PTEN, and knockdown of YY1 completely blocked IR-induced pS380-PTEN through PP2A. In conclusion, knockdown of YY1 enhanced TSCC radiosensitivity through PP2A-mediated dephosphorylation of PTEN Ser380; thus, antagonizing the IR-induced nuclear PTEN/Rad51 axis and targeting YY1 may reverse IR resistance in TSCC.

Expression of HIF­1α in cycling stretch­induced osteogenic differentiation of bone mesenchymal stem cells.

During orthodontic treatment, mechanical force is applied to the teeth, and following a series of complex metabolism changes, the position of the teeth in the alveolar bone change. This process is closely associated with primitive bone mesenchymal stem cells (BMSCs), which may differentiate into osteoblasts precursor cell. A hypoxic microenvironment may be caused by orthodontic mechanical forces between the alveolar bone and the root. Hypoxia­inducible factor 1α (HIF­1α) is a specific receptor that adapts to a hypoxic environment. The present study was designed to investigate whether HIF­1α was involved in the osteoblastic differentiation of BMSCs induced by cyclic tensile stress. During this process, HIF­1α mRNA and protein expression were detected using a reverse transcription­quantitative polymerase chain reaction and western blotting. It was revealed that alkaline phosphatase activity increased in a time­dependent manner in three different stretching strength groups, which indicates that cyclic stretch promotes the osteogenic differentiation of BMSCs. The optimal force stage of osteogenesis was an unexpected discovery, which will provide theoretical guidance for selecting the most suitable orthodontic force for tooth movement in clinical orthodontic treatment. Most importantly, all experiments revealed that HIF­1α mRNA and protein were significantly increased following stretching treatment in BMSCs. It was therefore concluded that HIF­1α may be involved in BMSCs modulating osteogenic metabolism during exposure to cyclic stretch and a hypoxic microenvironment, which may prove useful for the reconstruction of a jaw during orthodontic treatment.

Epigallocatechin-3-gallate inhibits proliferation and induces apoptosis in odontogenic keratocyst keratinocytes.

OBJECTIVE: The aim of this study was to investigate the effects of epigallocatechin-3-gallate on the proliferation and apoptosis of odontogenic keratocyst (OKC) keratinocytes in vitro. MATERIALS AND METHODS: Keratinocytes isolated from the epithelial lining of the OKC were cultured in keratinocyte serum-free medium and identified by CK10, CK14, pan-cytokeratin and vimentin immunofluorescence staining. The cells were exposed to EGCG at different concentrations, and proliferation inhibition was measured by cell counting kit 8 assay. Cell cycle and apoptosis were assessed by flow cytometry, and expression of the WNT signalling pathway-related proteins FZD3 and JNK3 was detected by quantitative real-time PCR and Western blotting. Human oral keratinocytes (HOKs) were used as the control. RESULTS: The OKC keratinocytes were successfully cultured. The primary cells were tile-like and expressed the epithelial biomarkers CK10, CK14 and pan-cytokeratin. Epigallocatechin-3-gallate inhibited cell proliferation in a dose- and time-dependent manner, arrested cell cycle in the G1 phase and induced apoptosis of OKC keratinocytes. FZD3 and JNK3 were overexpressed in OKC keratinocytes compared with HOKs and were downregulated by epigallocatechin-3-gallate treatment. CONCLUSION: Epigallocatechin-3-gallate inhibited proliferation and induced apoptosis in OKC keratinocytes, possibly by suppressing the WNT/JNK signalling pathway. It may thus be potentially used for OKC treatment.

Dietary Nitrate Protects Against Skin Flap Ischemia-Reperfusion Injury in Rats via Modulation of Antioxidative Action and Reduction of Inflammatory Responses.

Dietary nitrate, found abundant in green vegetables, can be absorbed into the blood and be converted to nitric oxide (NO) in the body. Dietary nitrate has been proved to have many positive physiological functions in the body. Here, we evaluated the therapeutic effects of dietary nitrate on skin flap recovery following ischemia reperfusion (IR). Wistar rats were pretreated with nitrate from one week prior to ischemia to the end of reperfusion. It was found that oral administration of nitrate increased serum nitrate and nitrite levels, protected cells from apoptosis, and attenuated flap tissue edema. In the meantime, the oxidative stress marker malondialdehyde was reduced, while the activities of antioxidant enzymes were restored after nitrate treatment. Moreover, the macrophage and neutrophil infiltration in the flap was significantly attenuated by nitrate supplementation, as were the pro-inflammatory cytokines. In sum, we found that oral administration of nitrate can attenuate skin flap IR injury through the regulation of oxidative stress and inflammatory response.

Clinical significance of cytokeratin in the cervical lymph nodes of patients with mandibular gingival squamous cell carcinoma.

The present study aims to analyze the expression of broad spectrum cytokeratin in the cervical lymph nodes of patients with mandibular gingival squamous cell carcinoma and explore the metastasis of mandibular gingival squamous cell carcinoma in cervical lymph nodes. This study included 42 patients with mandibular gingival squamous cell carcinoma, which was staged according to the clinical staging criteria by International Union Against Cancer 2002 (UICC) and the Level staging method of cervical lymph node by American Academy of Otolaryngology-Head and Neck Surgery 1991. Monoclonal mouse anti-human cytokeratin (AE1/AE3) antibody was used in immunohistochemical examination and hematoxylin and eosin (H&E) staining. All positive sections by H&E staining were also positive by immunohistochemistry (IHC). The positive rate of routine H&E staining and serial-section H&E staining was 8.03 and 9.57%, respectively, the positive rate of IHC was 12.82%. The positive rate of IHC was significantly different with that of routine H&E staining (χ2=7.17, P<0.01), yet not significantly different with that of serial-section H&E staining (χ2=3.10, P>0.05). Lymph node metastasis was mainly in Level I, II and III, both serial-section H&E staining and IHC showed lymph node metastasis in Level IV for advanced patients. IHC showed 19 lymph node micrometastasis in 12 patients, while neither serial-section nor routine H&E staining showed micrometastasis. Lymph node dissection of hyoid bone (mainly in Level I, II and III) could be used for early patients, and the dissection could be expanded to Level IV for advanced patients.

Comparing Modified with Conventional Parotidectomy for Benign Parotid Tumors.

PURPOSE: We conducted a study to compare the functional outcomes and surgical complications of patients with benign parotid tumors treated with conventional parotidectomy and modified parotidectomy. METHODS: This study retrospectively analyzed 99 patients who had benign parotid lesions and underwent parotidectomy using either conventional or modified parotidectomy. The operation time, cosmetic outcome, great auricular nerve anesthesia, incidence of Frey syndrome, and secretory function with the two techniques were compared. RESULTS: The mean operation time was shorter and the total complication rate was obviously lower in the modified surgery group (p < 0.001). In the modified surgery group, the incision was more cosmetic (p < 0.001), the sensory deficit rate was low (p < 0.001), and the sensory recovery rate was high, and transient facial paralysis and Frey syndrome were rare. Furthermore, glandular function was preserved in patients with a conserved Stensen duct. There was no tumor recurrence in the two groups during a mean follow-up of 29.8 months. CONCLUSION: Modified surgical techniques for benign parotid neoplasms significantly reduced the surgery time and improved the surgery outcomes compared with the conventional approach. This adds to the evidence to support the effectiveness of modified parotidectomy in selected patients with benign parotid tumors.

[Expression and clinical significance of the genes of Wnt signaling pathway in keratocystic odontogenic tumor of the jaw bones].

PURPOSE: To study the role of genes of Wnt signaling pathway in keratocystic odontogenic tumor (KCOT) of the jaw bones. METHODS: Fresh specimens of KCOT and the same patient 's normal oral mucosa were obtained. Then RNA was extracted. Gene chip was used to detect the genes of Wnt signaling pathway. RESULTS: Compared to normal oral mucosa, there were 5 genes of Wnt signaling pathway in KCOT changed, including CAMK2A down-regulated, FZD3, MAPK10, PRKX and WNT5a up-regulated. CONCLUSIONS: There are abnormal expressions of genes of Wnt pathway in KCOT. Genes of Wnt pathway plays certain roles in KCOT.

Gene mutations in the D-loop region of mitochondrial DNA in oral squamous cell carcinoma.

The present study aimed to investigate gene mutations in the displacement­loop (D­loop) region of mitochondrial DNA (mtDNA) in patients with oral squamous cell carcinoma (OSCC) in order to examine the role of gene mutation in mtDNA in OSCC tumorigenesis. mtDNA was obtained from cancer tissues, paracancerous tissues and normal mucosal tissues of thirty patients with OSCC. The D­loop region of the mtDNA was amplified using polymerase chain reaction, sequenced and then analyzed by Chromas software and BLAST to identify the mutation sites. Mutations in the D­loop region were observed in the cancer tissue samples of eight out of thirty cases with OSCC, with a mutation rate of 27%. There were nine mutations in total, including one point mutation, two base deletions, three insertion mutations and three heterozygous mutations. In these mutations, base deletions were different from each other and heterozygous mutations did not have the same mutation form; however, the three insertion mutations were the same, consisting of an insertion of a C base. One case contained a T/A heterozygous mutation as well as base insertion of C. The eight cases with mutations in the D­loop region consisted of three cases of tongue cancer, two cases of soft palate cancer, one case of floor of the mouth cancer, one case of oropharyngeal cancer and one case of lip cancer. This study demonstrated mutations in the mtDNA D­loop region in OSCC cells; however, the association between occurrences of OSCC and mtDNA mutations requires further investigation.