Identification of Potential Candidate Genes of Oral Cancer in Response to Chronic Infection With Porphyromonas gingivalis Using Bioinformatical Analyses

The role of periodontitis in cancer development, with a focus on oral cancers

Periodontitis is a severe gum infection that begins as gingivitis and can lead to gum recession, bone loss, and tooth loss if left untreated. It is primarily caused by bacterial infection, which triggers inflammation and the formation of periodontal pockets. Notably, periodontitis is associated with systemic health issues and has been linked to heart disease, diabetes, respiratory diseases, adverse pregnancy outcomes, and cancers. Accordingly, the presence of chronic inflammation and immune system dysregulation in individuals with periodontitis significantly contributes to the initiation and progression of various cancers, particularly oral cancers. These processes promote genetic mutations, impair DNA repair mechanisms, and create a tumor-supportive environment. Moreover, the bacteria associated with periodontitis produce harmful byproducts and toxins that directly damage the DNA within oral cells, exacerbating cancer development. In addition, chronic inflammation not only stimulates cell proliferation but also inhibits apoptosis, causes DNA damage, and triggers the release of pro-inflammatory cytokines. Collectively, these factors play a crucial role in the progression of cancer in individuals affected by periodontitis. Further, specific viral and bacterial agents, such as hepatitis B and C viruses, human papillomavirus (HPV), Helicobacter pylori (H. pylori), and Porphyromonas gingivalis, contribute to cancer development through distinct mechanisms. Bacterial infections have systemic implications for cancer development, while viral infections provoke immune and inflammatory responses that can lead to genetic mutations. This review will elucidate the link between periodontitis and cancers, particularly oral cancers, exploring their underlying mechanisms to provide insights for future research and treatment advancements.

lncRNA TMEM161B-AS1 screened the onset of oral squamous cell carcinoma in HPV-infected patients, predicted poor prognosis, and regulated cell progression via modulating the miR-651-5p/BDNF axis

Oral squamous cell carcinoma (OSCC) has become the most common HPV-related cancer with high invasion and metastasis. Exploring biomarkers for the screening and monitoring of OSCC, especially for the HPV-OSCC, would benefit patients' diagnosis and prognosis. This study evaluated the significance and mechanism of TMEM161B-AS1 and miR-651-5p in HPV-OSCC aiming to provide novel insight into the mechanism of HPV-OSCC development. Expression of TMEM161B-AS1 and miR-561-5p was analyzed in healthy individuals, HPV-infected non-OSCC patients, and HPV-OSCC patients using PCR. Their significance in HPV-OSCC occurrence and prognosis was evaluated by logistic regression, ROC, Kaplan-Meier, and Cox regression analysis. In OSCC cells, CCK8 and Transwell assays were employed for assessing cell growth and metastasis. The luciferase reporter assay and cell transfection were performed to evaluate the regulatory association between TMEM161B-AS1, miR-561-5p, and BDNF. Significant upregulation of TMEM161B-AS1 and downregulation of miR-561-5p were observed in oral HPV-infected patients. Both TMEM161B-AS1 and miR-651-5p served as risk factors for the occurrence of OSCC in oral HPV-infected patients and could distinguish HPV-OSCC patients from HPV-infected non-OSCC patients. Increased TMEM161B-AS1 and reduced miR-561-5p indicated severe development and adverse prognosis of HPV-OSCC patients. In OSCC cells, silencing TMEM161-AS1 suppressed cell proliferation and motility via negatively modulating miR-561-5p. miR-561-5p negatively regulated BDNF, which was considered the underlying mechanism of TMEM161B-AS1. Increasing TMEM161B-AS expression and decreasing miR-561-5p showed the occurrence of OSCC in HPV-infected patients and predicted malignant development and adverse prognosis. TMEME161B-AS1 served as a tumor promoter via regulating the miR-561-5p/BDNF axis.

Transcriptomic analysis of Porphyromonas gingivalis-infected head and neck cancer cells: Identification of PLAU as a candidate prognostic biomarker

Periodontal disease is a risk factor for head and neck squamous cell carcinoma (HNSCC), and Porphyromonas gingivalis, a major periodontal pathogen, has been identified as a specific and potentially independent microbial factor that increases the risk of cancer mortality. Gene expression in HNSCC due to P. gingivalis infection and how changes in gene expression affect the prognosis of HNSCC patients are not clarified. When P. gingivalis was cultured with HNSCC cells, it efficiently adhered to these cells and enhanced their invasive ability. A transcriptome analysis of P. gingivalis -infected HNSCC cells showed that genes related to migration, including CCL20, CITED2, CTGF, C8orf44-SGK3, DUSP10, EGR3, FUZ, HBEGF, IL1B, IL24, JUN, PLAU, PTGS2, P2RY1, SEMA7A, SGK1 and SIX2, were highly up- or down-regulated. The expression of up-regulated genes was examined using the expression data of HNSCC patients obtained from The Cancer Genome Atlas (TCGA) database, and the expression of 5 genes, including PLAU, was found to be higher in cancer tissue than in solid normal tissue. An analysis of protein-protein interactions revealed that these 5 genes formed a dense network. A Cox regression analysis showed that high PLAU expression levels were associated with a poor prognosis in patients with TCGA-HNSCC. Furthermore, the prognostic impact correlated with tumour size and the presence or absence of lymph node metastasis. Collectively, these results suggest the potential of PLAU as a molecular prognostic marker in HNSCC patients. Further in vivo and in vitro studies are needed to verify the findings of this study.

Is Systemic Immunosuppression a Risk Factor for Oral Cancer? A Systematic Review and Meta-Analysis

Even if the relationship between immunosuppression and increased incidence of systemic cancers is well known, there is less awareness about the risk of developing oral cancer in immunosuppressed patients. The aim of this review was to evaluate the association between immunosuppression and the development of oral cancer. Two authors independently and, in duplicate, conducted a systematic literature review of international journals and electronic databases (MEDLINE via OVID, Scopus, and Web of Science) from their inception to 28 April 2023. The assessment of risk of bias and overall quality of evidence was performed using the Newcastle-Ottawa Scale and GRADE system. A total of 2843 articles was identified, of which 44 met the inclusion criteria and were included in either the qualitative or quantitative analysis. The methodological quality of the included studies was generally high or moderate. The quantitative analysis of the studies revealed that immunosuppression should be considered a risk factor for the development of oral cancer, with a percentage of increased risk ranging from 0.2% to 1% (95% CI: 0.2% to 1.4%). In conclusion, the results suggest that a constant and accurate follow-up should be reserved for all immunosuppressed patients as a crucial strategy to intercept lesions that have an increased potential to evolve into oral cancer.

Squamous Cell Carcinoma Arising From Odontogenic Cyst Epithelium or Oral Mucosa Epithelium After Marsupialization of Odontogenic Radicular Cyst in Posterior Mandible?

Squamous cell carcinomas (SCCs) are common malignant tumors in the oral and maxillofacial region. However, SCCs secondary to marsupialization of odontogenic radicular cysts are extremely rare. The authors report an unusual case of a 43-year-old male presented with dull pain in the right molar region of the mandible without numbness of lower lips, who had a long history of smoking, alcohol consumption, and betel nut chewing. Computerized tomography revealed a round well-defined unilocular radiolucent at the apex of lower right premolars, 2 nonvital teeth. The clinical diagnosis was the radicular cyst of the right mandible. The patient was initially treated with root canal therapy of the teeth followed by marsupialization with a mandibular vestibular groove incision. While the patient did not follow the instruction of irrigation of the cyst and had no regular follow-up. The reexamination of computerized tomography indicated a round well-defined unilocular radiolucent at the apex of lower right premolars and filled with a soft tissue without clear boundary with buccal muscles at 31 months follow-up. There were no masses or ulcer around the mandibular vestibular groove incision and the patient had no sign of numbness of lower lips. The clinical diagnosis was the radicular cyst of right mandible with infection. A curettage was performed. However, the pathologic diagnosis was well-differentiated SCC. An extended radical surgical resection including segmental resection of the right mandible was performed. The histopathology was well-differentiated SCC without the cyst epithelium and invasion of bone, which can be distinguished from primary intraosseous SCC. The case indicates that marsupialization performed in patients with a history of smoking, alcohol consumption, and betel nut chewing, has a risk of suffering from oral SCC.

Periodontitis and Its Inflammatory Changes Linked to Various Systemic Diseases: A Review of Its Underlying Mechanisms

Periodontitis is a chronic inflammatory disease of the gums. The incidence of periodontitis is increasing all over the world. In patients with periodontitis, there is gradual destruction of the periodontal ligament and the alveolar bone, and later, in advanced stages, there is tooth loss. Different microorganisms, the host’s immune response, and various environmental factors interact in the progression of this chronic inflammatory disease. In the present review, we discuss the epidemiology, clinical features, diagnosis, and complications of periodontitis. We also discuss the association of chronic inflammation found in periodontitis with various other systemic diseases, which include cardiovascular, respiratory, diabetes, Alzheimer’s, cancer, adverse pregnancy, and multiple myeloma, and also highlight microbial carcinogenesis and the microRNAs involved. The latest updates on the molecular mechanism, possible biomarkers, and treatment procedures may be beneficial for diagnostic and therapeutic purposes.

Exploring the Novel Computational Drug Target and Associated Key Pathways of Oral Cancer

Oral cancer (OC) is a serious health concern that has a high fatality rate. The oral cavity has seven kinds of OC, including the lip, tongue, and floor of the mouth, as well as the buccal, hard palate, alveolar, retromolar trigone, and soft palate. The goal of this study is to look into new biomarkers and important pathways that might be used as diagnostic biomarkers and therapeutic candidates in OC. The publicly available repository the Gene Expression Omnibus (GEO) was to the source for the collection of OC-related datasets. GSE74530, GSE23558, and GSE3524 microarray datasets were collected for analysis. Minimum cut-off criteria of |log fold-change (FC)| > 1 and adjusted p < 0.05 were applied to calculate the upregulated and downregulated differential expression genes (DEGs) from the three datasets. After that only common DEGs in all three datasets were collected to apply further analysis. Gene ontology (GO) and pathway analysis were implemented to explore the functional behaviors of DEGs. Then protein−protein interaction (PPI) networks were built to identify the most active genes, and a clustering algorithm was also implemented to identify complex parts of PPI. TF-miRNA networks were also constructed to study OC-associated DEGs in-depth. Finally, top gene performers from PPI networks were used to apply drug signature analysis. After applying filtration and cut-off criteria, 2508, 3377, and 670 DEGs were found for GSE74530, GSE23558, and GSE3524 respectively, and 166 common DEGs were found in every dataset. The GO annotation remarks that most of the DEGs were associated with the terms of type I interferon signaling pathway. The pathways of KEGG reported that the common DEGs are related to the cell cycle and influenza A. The PPI network holds 88 nodes and 492 edges, and CDC6 had the highest number of connections. Four clusters were identified from the PPI. Drug signatures doxorubicin and resveratrol showed high significance according to the hub genes. We anticipate that our bioinformatics research will aid in the definition of OC pathophysiology and the development of new therapies for OC.

Periodontal Pathogens: A Crucial Link Between Periodontal Diseases and Oral Cancer

Emerging evidence shows a striking link between periodontal diseases and various human cancers including oral cancer. And periodontal pathogens, leading to periodontal diseases development, may serve a crucial role in oral cancer. This review elucidated the molecular mechanisms of periodontal pathogens in oral cancer. The pathogens directly engage in their own unique molecular dialogue with the host epithelium to acquire cancer phenotypes, and indirectly induce a proinflammatory environment and carcinogenic substance in favor of cancer development. And functional, rather than compositional, properties of oral microbial community correlated with cancer development are discussed. The effect of periodontal pathogens on periodontal diseases and oral cancer will further detail the pathogenesis of oral cancer and intensify the need of maintaining oral hygiene for the prevention of oral diseases including oral cancer.

Oral Microbiota-Driven Cell Migration in Carcinogenesis and Metastasis

The oral cavity harbors approximately 1,000 microbial species, and both pathogenic and commensal strains are involved in the development of carcinogenesis by stimulating chronic inflammation, affecting cell proliferation, and inhibiting cell apoptosis. Moreover, some substances produced by oral bacteria can also act in a carcinogenic manner. The link between oral microbiota and chronic inflammation as well as cell proliferation has been well established. Recently, increasing evidence has indicated the association of the oral microbiota with cell migration, which is crucial in regulating devastating diseases such as cancer. For instance, increased cell migration induced the spread of highly malignant cancer cells. Due to advanced technologies, the mechanistic understanding of cell migration in carcinogenesis and cancer metastasis is undergoing rapid progress. Thus, this review addressed the complexities of cell migration in carcinogenesis and cancer metastasis. We also integrate recent findings on the molecular mechanisms by which the oral microbiota regulates cell migration, with emphasis on the effect of the oral microbiota on adhesion, polarization, and guidance. Finally, we also highlight critical techniques, such as intravital microscopy and superresolution microscopy, for studies in this field.

Differential gene expression and network analysis in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a prevalent malignancy with a poor prognosis, whose biomarkers have not been studied in great detail. We have collected genomic data of HNSCC patients from The Cancer Genome Atlas (TCGA) and analyzed them to get deeper insights into the gene expression pattern. Initially, 793 differentially expressed genes (DEGs) were categorized, and their enrichment analysis was performed. Later, a protein-protein interaction network for the DEGs was constructed using the STRING plugin in Cytoscape to study their interactions. A set of 10 hub genes was selected based on Maximal Clique Centrality score, and later their survival analysis was studied. The elucidated set of 10 genes, i.e., PRAME, MAGEC2, MAGEA12, LHX1, MAGEA3, CSAG1, MAGEA6, LCE6A, LCE2D, LCE2C, referred to as potential candidates to be explored as HNSCC biomarkers. The Kaplan-Meier overall survival of the selected genes suggested that the alterations in the candidate genes were linked to the decreased survival of the HNSCC patients. Altogether, the results of this study signify that the genomic alterations and differential expression of the selected genes can be explored in therapeutic interpolations of HNSCC, exploiting early diagnosis and target-propelled therapy.

Periodontitis as a risk for oral cancer: a case-control study

Background

The aetiology of oral cancer is multifactorial, as various risk factors (genetics, socioeconomic and lifestyle factors) contribute to its development. Data in the literature suggest that people with periodontal disease have an increased risk of developing oral cancer, and the severity of periodontitis correlates with the appearance of oral squamous cell carcinoma. The aim of this study was to revise the non-genetic risk factors that may influence the development of OC, while focusing on the dental and periodontal status and OH.

Methods

Two hundred patients (hundred diagnosed with oral cancer and hundred without oral cancer) were enrolled in our case–control study, to evaluate the association between oral cancer and the presence and severity of periodontitis, while examining several risk factors that might be responsible for oral cancer formation. A questionnaire customised for oral cancer patients was used to obtain the socioeconomic and lifestyle risk factors that may influence the development of oral squamous cell carcinoma. The dental and periodontal status along with the level of oral hygiene was recorded quantitatively. The chi-square and Mann–Whitney tests and logistic regression were used for the statistical analysis.

Results

By considering both the case and the control groups, a significant correlation was found between the incidence of oral cancer and some socioeconomic factors and lifestyle habits, such as the sex, age, education and alcohol consumption of an individual. The mean value of the Silness-Löe plaque index was significantly higher in the case population. The number of completely edentulous patients was higher among the oral cancer population. The incidence of oral cancer was 57.1% in patients with periodontal disease. In comparison, the incidence of oral squamous cell carcinoma was only 28.6% among the patients without periodontitis. Most of the oral cancer patients (72.1%) had stage 4 periodontitis. On the other hand, the vast majority of the control group (51.6%) had stage 2 periodontitis.

Conclusion

Periodontitis can be an individual risk factor for oral cancer development. Periodontally compromised individuals should be strictly monitored, especially those with severe periodontitis and coexisting lifestyle risk factors. Maintaining their periodontal health in at-risk patients can minimize cancer risks.

Periodontitis as a risk factor for head and neck cancer

Background

Periodontitis may be associated with the development of head and neck cancer (HNC). A literature review was conducted to understand the possible association between them.

Material and Methods

Articles published in the PubMed database from January 1999 and May 2020 were retrieved. Limitations of the studies and biological mechanisms were discussed.

Results

A total of 4,232 articles were found. Of these, 13 were analyzed according to inclusion criteria. Most papers found some association between periodontitis and HNC, although differences in periodontal evaluation, sample size, study design and tumor sites were observed. Porphyromonas gingivalis appears to increase the chance of both diseases, and it may be one of their main potential risk factors. Genetic predisposition is increased by exposure to environmental factors which can directly induce epigenetic changes that contribute to these diseases.

Conclusions

Understanding the mechanisms related to periodontitis and HNC has increased, however, well-designed clinical studies are needed for better conclusions. Furthermore, the advent of multiple "omic" technologies will help comprehend their possible association.

Key words:Periodontitis, head and neck cancer, oral cancer, risk factors, biological factors.

Linking chronic periodontitis and oral cancer: A review

The aim of this article is to survey the accessible writing on the pathogenetic systems engaged with the relationship between oral malignancy and periodontitis. Gingival tissue contains multiple microbiota, which can induce inflammatory reactions. This reaction plays a crucial role in assessing the susceptibility of patients to periodontal diseases. The link between chronic periodontitis and the risk of malignancy through this inflammation of the affected epithelium have been studied thoroughly. Many studies have reported that, chronic periodontitis has systemic influence which has high risk of developing different types of cancers. Also, various confounding factors such as consumption of alcohol, smoking, diet, age and gender have been found to be associated with both chronic periodontitis and oral cancer. An online quest for a wide range of articles distributed was started utilizing MEDLINE/PubMed, with the keywords, for example, 'oral squamous cell carcinoma (OSCC)', 'oral microbiota,' 'microorganisms and malignancy and Porphyromonas gingivalis. This review aimed to study the current literature linking chronic periodontitis and oral cancer.

Bioinformatics and immunohistochemistry analyses of expression levels and clinical significance of CXCL2 and TANs in an oral squamous cell carcinoma tumor microenvironment of Prophyromonas gingivalis infection

The present study aimed to detect the immunoexpression and clinical significance of Porphyromonas gingivalis (P. gingivalis) in the tumor microenvironment (TME) of oral squamous cell carcinoma (OSCC). The immunoexpression of P. gingivalis in OSCC tissues was detected via immunohistochemistry (IHC) after P. gingivalis was infected into the TME of OSCC. To identify the differentially expressed genes in the carcinogenesis and progression of OSCC with P. gingivalis infection, microarray datasets (GSE87539 and GSE138206) were downloaded from the Gene Expression Omnibus database. The immunoexpression levels of C-X-C motif chemokine ligand 2 (CXCL2) and tumor-associated neutrophils (TANs) were also evaluated via IHC, and the immunoexpression levels of all three clinical variables were analyzed using χ² or Fisher's exact tests. The survival rates were calculated using the Kaplan-Meier method and the survival curves were compared using log-rank tests. Predominantly strong immunoexpression of P. gingivalis was identified in OSCC samples. CXCL2 was considered to be a differential gene in the two datasets. Immunoexpression of P. gingivalis was positively associated with CXCL2 and TANs expression. Furthermore, P. gingivalis was associated with survival status (P<0.001) and differentiation (P<0.001). CXCL2 was associated with age (P=0.038) and survival status (P=0.003), while TANs were associated with T stage (P=0.015) and clinical stage (P=0.002). These clinical variables were considered to be independent risk factors for the poor prognosis of patients with OSCC. Collectively, the results suggested that the immunoexpression of P. gingivalis may be positively associated with CXCL2 and TANs. In addition, the strong immunoexpression levels of P. gingivalis, CXCL2 and TANs may be associated with a poor prognosis in patients with OSCC.

Effect of Periodontitis and Scaling and Root Planing on Risk of Pharyngeal Cancer: A Nested Case-Control Study

This study investigated the association between periodontitis and the risk of pharyngeal cancer in Taiwan. For this population-based nested case–control study using the Longitudinal Health Insurance Database derived from Taiwan’s National Health Insurance Research Database, we identified patients (n = 1292) who were newly diagnosed with pharyngeal cancer between 2005 and 2013 and exactly paired them with propensity score matched control subjects (n = 2584). Periodontitis and scaling and root planing (SRP) were identified before the index date. Pharyngeal cancer was subdivided into 3 subgroups on the basis of anatomic location: nasopharyngeal cancer, oropharyngeal cancer, and hypopharyngeal cancer. A multiple conditional logistic regression model was applied to analyze the adjusted odds ratio (aOR). Periodontitis was associated with an increased risk of pharyngeal cancer (aOR, 1.57; 95% confidence interval (CI), 1.17 to 2.10), especially oropharyngeal cancer (aOR, 2.22; 95% CI, 1.07 to 4.60). We found a decreased risk of pharyngeal cancer in patients who had undergone SRP (aOR, 0.77; 95% CI, 0.61 to 0.96). In conclusion, this study showed that periodontitis was associated with an increased risk of pharyngeal cancer and SRP exerted a protective effect against pharyngeal cancer. Our results suggest that treating periodontitis and performing SRP, which are modifiable factors in oral health, in clinical practice may provide an opportunity to decrease the disease burden of pharyngeal cancer in Taiwan.

Analysis of differentially expressed genes in oral epithelial cells infected with Fusobacterium nucleatum for revealing genes associated with oral cancer

Accumulating evidence links Fusobacterium nucleatum with tumorigenesis. Our previous study demonstrated that F. nucleatum infection can induce epithelial‐mesenchymal transition (EMT) in oral epithelial cells and elaborated a probable signal pathway involved in the induction of EMT. However, the comprehensive profiling and pathways of other candidate genes involved in F. nucleatum promoting malignant transformation remain largely elusive. Here, we analysed the transcriptome profile of HIOECs exposed to F. nucleatum infection. Totally, 3307 mRNAs (ǀLog2FCǀ >1.5) and 522 lncRNAs (ǀLog2FCǀ >1) were identified to be differentially expressed in F. nucleatum‐infected HIOECs compared with non‐infected HIOECs. GO and KEGG pathway analyses were performed to investigate the potential functions of the dysregulated genes. Tumour‐associated genes were integrated, and top 10 hub genes (FYN, RAF1, ATM, FOS, CREB, NCOA3, VEGFA, JAK2, CREM and ATF3) were identified by protein‐protein interaction (PPI) network, and Oncomine was used to validate hub genes' expression. LncRNA‐hub genes co‐expression network comprising 67 dysregulated lncRNAs were generated. Together, our study revealed the alteration of lncRNA and potential hub genes in oral epithelial cells in response to F. nucleatum infection, which may provide new insights into the shift of normal to malignant transformation initiated by oral bacterial infection.

LL-37-Induced Autophagy Contributed to the Elimination of Live Porphyromonas gingivalis Internalized in Keratinocytes

Porphyromonas gingivalis (P. gingivalis), one of the most important pathogens of periodontitis, is closely associated with the aggravation and recurrence of periodontitis and systemic diseases. Antibacterial peptide LL-37, transcribed from the cathelicidin antimicrobial peptide (CAMP) gene, exhibits a broad spectrum of antibacterial activity and regulates the immune system. In this study, we demonstrated that LL-37 reduced the number of live P. gingivalis (ATCC 33277) in HaCaT cells in a dose-dependent manner via an antibiotic-protection assay. LL-37 promoted autophagy of HaCaT cells internalized with P. gingivalis. Inhibition of autophagy with 3-methyladenine (3-MA) weakened the inhibitory effect of LL-37 on the number of intracellular P. gingivalis. A cluster of orthologous groups (COGs) and a gene ontology (GO) functional analysis were used to individually assign 65 (10%) differentially expressed genes (DEGs) to an "Intracellular trafficking, secretion, and vesicular transport" cluster and 306 (47.08%) DEGs to metabolic processes including autophagy. Autophagy-related genes, a tripartite motif-containing 22 (TRIM22), and lysosomal-associated membrane protein 3 (LAMP3) were identified as potentially involved in LL-37-induced autophagy. Finally, bioinformatics software was utilized to construct and predict the protein-protein interaction (PPI) network of CAMP-TRIM22/LAMP3-Autophagy. The findings indicated that LL-37 can reduce the quantity of live P. gingivalis internalized in HaCaT cells by promoting autophagy in these cells. The transcriptome sequencing and analysis also revealed the potential molecular pathway of LL-37-induced autophagy.

Role of the oral microbiota in cancer evolution and progression

Bacteria identified in the oral cavity are highly complicated. They include approximately 1000 species with a diverse variety of commensal microbes that play crucial roles in the health status of individuals. Epidemiological studies related to molecular pathology have revealed that there is a close relationship between oral microbiota and tumor occurrence. Oral microbiota has attracted considerable attention for its role in in‐situ or distant tumor progression. Anaerobic oral bacteria with potential pathogenic abilities, especially Fusobacterium nucleatum and Porphyromonas gingivalis, are well studied and have close relationships with various types of carcinomas. Some aerobic bacteria such as Parvimonas are also linked to tumorigenesis. Moreover, human papillomavirus, oral fungi, and parasites are closely associated with oropharyngeal carcinoma. Microbial dysbiosis, colonization, and translocation of oral microbiota are necessary for implementation of carcinogenic functions. Various underlying mechanisms of oral microbiota‐induced carcinogenesis have been reported including excessive inflammatory reaction, immunosuppression of host, promotion of malignant transformation, antiapoptotic activity, and secretion of carcinogens. In this review, we have systemically described the impact of oral microbial abnormalities on carcinogenesis and the future directions in this field for bringing in new ideas for effective prevention of tumors.

The Bacterial Microbiota of Gastrointestinal Cancers: Role in Cancer Pathogenesis and Therapeutic Perspectives

The microbiota has an essential role in the pathogenesis of many gastrointestinal diseases including cancer. This effect is mediated through different mechanisms such as damaging DNA, activation of oncogenic pathways, production of carcinogenic metabolites, stimulation of chronic inflammation, and inhibition of antitumor immunity. Recently, the concept of "pharmacomicrobiomics" has emerged as a new field concerned with exploring the interplay between drugs and microbes. Mounting evidence indicates that the microbiota and their metabolites have a major impact on the pharmacodynamics and therapeutic responses toward anticancer drugs including conventional chemotherapy and molecular-targeted therapeutics. In addition, microbiota appears as an attractive target for cancer prevention and treatment. In this review, we discuss the role of bacterial microbiota in the pathogenesis of different cancer types affecting the gastrointestinal tract system. We also scrutinize the evidence regarding the role of microbiota in anticancer drug responses. Further, we discuss the use of probiotics, fecal microbiota transplantation, and antibiotics, either alone or in combination with anticancer drugs for prevention and treatment of gastrointestinal tract cancers.

Porphyromonas gingivalis Promotes Oral Squamous Cell Carcinoma Progression in an Immune Microenvironment

Increasing evidence has revealed a significant association between microorganisms and oral squamous cell carcinoma (OSCC). Porphyromonas gingivalis, the keystone pathogen in chronic periodontitis, is considered an important potential etiologic agent of OSCC, but the underlying immune mechanisms through which P. gingivalis mediates tumor progression of the oral cancer remain poorly understood. Our cohort study showed that the localization of P. gingivalis in tumor tissues was related to poor survival of patients with OSCC. Moreover, P. gingivalis infection increased oral lesion multiplicity and size and promoted tumor progression in a 4-nitroquinoline-1 oxide (4NQO)–induced carcinogenesis mouse model by invading the oral lesions. In addition, CD11b+ myeloid cells and myeloid-derived suppressor cells (MDSCs) showed increased infiltration of oral lesions. Furthermore, in vitro observations showed that MDSCs accumulated when human-derived dysplastic oral keratinocytes (DOKs) were exposed to P. gingivalis, and CXCL2, CCL2, interleukin (IL)–6, and IL-8 may be potential candidate genes that facilitate the recruitment of MDSCs. Taken together, our findings suggest that P. gingivalis promotes tumor progression by generating a cancer-promoting microenvironment, indicating a close relationship among P. gingivalis, tumor progression of the oral cancer, and immune responses.

Expression and Prognostic Value of IFIT1 and IFITM3 in Head and Neck Squamous Cell Carcinoma

OBJECTIVES

Interferon-induced protein with tetratricopeptide repeats 1 (IFIT1) and interferon-induced transmembrane protein 3 (IFITM3) are commonly induced by type I interferon. The study aims to investigate the expression and clinical significance of IFIT1 and IFITM3 in head and neck squamous cell carcinoma (HNSCC).

METHODS

Immunohistochemistry was applied on tissue microarray to reveal IFIT1 and IFITM3 expression in 275 HNSCC, 69 dysplasia, and 42 normal mucosa samples. The clinicopathologic features associated with IFIT1 and IFITM3 expression in HNSCC patients were analyzed.

RESULTS

IFIT1 and IFITM3 were highly expressed in HNSCC tissues. High expression of IFIT1 and IFITM3 predicts a negative prognosis for patients (P < .01). IFIT1 and IFITM3 expression was associated with programmed cell death ligand 1, B7-H4, V-domain Ig suppressor of T-cell activation, indoleamine 2,3-dioxygenase, and macrophage marker immunoreactivity.

CONCLUSIONS

IFIT1 and IFITM3 were overexpressed in HNSCC and indicated poor prognoses for patients with HNSCC. IFIT1 and IFITM3 expression was correlated with several immune checkpoint molecules and tumor-associated macrophage markers.

Identification of key genes and pathways of diagnosis and prognosis in cervical cancer by bioinformatics analysis

Background

Cervical cancer as one of the most common malignant tumors lead to bad prognosis among women. Some researches already focus on the carcinogenesis and pathogenesis of cervical cancer, but it is still necessary to identify more key genes and pathways.

Methods

Differentially expressed genes were identified by GEO2R from the gene expression omnibus (GEO) website, then gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyzed by DAVID. Meanwhile, protein–protein interaction network was constructed by STRING, and both key genes and modules were found in visualizing network through Cytoscape. Besides, GEPIA did the differential expression of key genes and survival analysis. Finally, the expression of genes related to prognosis was further explored by UNLCAN, oncomine, and the human protein atlas.

Results

Totally 57 differentially expressed genes were founded, not only enriched in G1/S transition of mitotic cell cycle, mitotic nuclear division, and cell division but also participated in cytokine–cytokine receptor interaction, toll‐like receptor signaling pathway, and amoebiasis. Additionally, 12 hub genes and 3 key modules were screened in the Cytoscape visualization network. Further survival analysis showed that TYMS (OMIM accession number 188350), MCM2 (OMIM accession number 116945), HELLS (OMIM accession number 603946), TOP2A (OMIM accession number 126430), and CXCL8 (OMIM accession number 146930) were associated with the prognosis of cervical cancer.

Conclusion

This study aim to better understand the characteristics of some genes and signaling pathways about cervical cancer by bioinformatics, and could provide further research ideas to find new mechanism, more prognostic factors, and potential therapeutic targets for cervical cancer.

From Beyond the Pale to the Pale Riders: The Emerging Association of Bacteria with Oral Cancer

Oral cancer, predominantly oral squamous cell carcinoma (OSCC), is the eighth-most common cancer worldwide, with a 5-y survival rate <50%. There are numerous risk factors for oral cancer, among which periodontal disease is gaining increasing recognition. The creation of a sustained dysbiotic proinflammatory environment by periodontal bacteria may serve to functionally link periodontal disease and oral cancer. Moreover, traditional periodontal pathogens, such as Porphyromonas gingivalis, Fusobacterium nucleatum, and Treponema denticola, are among the species most frequently identified as being enriched in OSCC, and they possess a number of oncogenic properties. These organisms share the ability to attach and invade oral epithelial cells, and from there each undergoes its own unique molecular dialogue with the host epithelium, which ultimately converges on acquired phenotypes associated with cancer, including inhibition of apoptosis, increased proliferation, and activation of epithelial-to-mesenchymal transition leading to increased migration of epithelial cells. Additionally, emerging properties of structured bacterial communities may increase oncogenic potential, and consortia of P. gingivalis and F. nucleatum are synergistically pathogenic within in vivo oral cancer models. Interestingly, however, some species of oral streptococci can antagonize the phenotypes induced by P. gingivalis, indicating functionally specialized roles for bacteria in oncogenic communities. Transcriptomic data support the concept that functional, rather than compositional, properties of oral bacterial communities have more relevance to cancer development. Collectively, the evidence is consistent with a modified polymicrobial synergy and dysbiosis model for bacterial involvement in OSCC, with driver mutations generating a conducive microenvironment on the epithelial boundary, which becomes further dysbiotic by the synergistic action of bacterial communities.

Periodontitis and oral cancer - current concepts of the etiopathogenesis

Gingival tissues are attacked by oral pathogens which can induce inflammatory reactions. The immune-inflammatory responses play essential roles in the patient susceptibility to periodontal diseases. There is a wealth of evidence indicating a link between chronic inflammation and risk of malignant transformation of the affected oral epithelium. Periodontitis is associated with an increased risk of developing chronic systemic conditions including autoimmune diseases and different types of cancers. Besides, some risk factors such as smoking, alcohol consumption and human papilloma virus have been found to be associated with both periodontitis and oral cancer. This review article aimed to study the current concepts in pathogenesis of chronic periodontitis and oral cancer by reviewing the related articles.

Distinct gene expression characteristics in epithelial cell-Porphyromonas gingivalis interactions by integrating transcriptome analyses

Porphyromonas gingivalis is a pivotal periodontal pathogen, and the epithelial cells serve as the first physical barrier to defend the host from bacterial attack. Within this host-bacteria interaction, P. gingivalis can modify the host immune reaction and adjust the gene expression, which is associated with periodontitis pathogenesis and developing strategies. Herein, a meta-analysis was made to get the differential gene expression profiles in epithelial cells with or without P. gingivalis infection. The network-based meta-analysis program for gene expression profiling was used. Both the gene ontology analysis and the pathway enrichment analysis of the differentially expressed genes were conducted. Our results determined that 290 genes were consistently up-regulated in P. gingivalis infected epithelial cells. 229 gene ontology biological process terms of up-regulated genes were discovered, including "negative regulation of apoptotic process" and "positive regulation of cell proliferation/migration/angiogenesis". In addition to the well-known inflammatory signaling pathways, the pathway associated with a transcriptional misregulation in cancer has also been increased. Our findings indicated that P. gingivalis benefited from the survival of epithelial cells, and got its success as a colonizer in oral epithelium. The results also suggested that infection of P. gingivalis might contribute to oral cancer through chronic inflammation. Negative regulation of the apoptotic process and transcriptional misregulation in cancer pathway are important contributors to the cellular physiology changes during infection development, which have particular relevance to the pathogenesis and progressions of periodontitis, even to the occurrence of oral cancer.