Associations Between Poor Oral Health and Risk of Squamous Cell Carcinoma of the Head and Neck: A Meta-Analysis of Observational Studies

A Systematic Review and Meta-Analysis Assessing the Role of Oral Health as a Risk Factor in Oral Cancer

Oral squamous cell carcinoma is the leading type of cancer in Southeast Asian countries and many parts of the world. Many factors increase the risk of oral cancer, like tobacco, betel nuts, alcohol consumption, sharp teeth, infections, and other factors. Oral health-related issues have been reported in many studies of oral cancer, but there is a need to understand the role of the same as a risk factor. The systematic review and meta-analysis were conducted to assess the role of oral health as a risk factor in oral cancer. The population diagnosed with oral cancer (P) of all age groups and both gender, exposure (E) is oral health (includes poor oral hygiene, periodontal disease, and other oral diseases excluding oral potentially malignant disorders (OPMD)), the comparator (C), is patients without oral health issues, outcome (O) is the role of poor oral health as a risk factor for oral cancer. A systematic review and meta-analysis were conducted. The databases used for the search were PubMed, Cochrane Database, Embase, Scopus, and Google Scholar. The unpublished reports, reviews, and grey literature were considered. Case-control studies were included assessing poor oral health as a risk factor with odds ratio as an effective measure. Newcastle Ottawa Scale for risk of bias in the case-control study was considered. The study results showed that tooth loss odds ratio (OR)=1.13, CI (0.99-1.26), I² value of 71.7%, Oral hygiene OR=1.29, CI (1.04-1.54), I² value of 19.7% and in periodontal diseases OR=2.14 CI (1.70-2.58), I² value of 75.3% had a higher risk of developing oral cancer. The risk factors for tooth loss and periodontal disease showed moderate heterogenicity and less heterogenicity for oral hygiene. Poor oral health factors such as periodontal disease, poor oral hygiene, and loss of teeth show higher odds of oral cancer than the control. The periodontal disease shows the highest odds than other factors. These risk factors can be considered for the primordial prevention of oral cancer.

miR-125b Promotes the Proliferation, Migration and Invasion of Oral Squamous Cell Carcinoma (OSCC)

miR-125b is involved in several tumors. However, miR-125b’s role in oral squamous cell carcinoma (OSCC) is unclear. Tumor tissues and oral normal mucosa tissues of OSCC patients were collected to measure miR-125b level. Oral cancer Tca8113 cells were separated into control group, miR-125b inhibitor group, and miR-125b mimics group, followed by measuring miR-125b level by real time PCR, cell survival, migration and invasion, PI3K/mTOR signaling protein level by Western blot. miR-125b was upregulated in OSCC tumor tissues and related to clinical/TNM stage, metastasis and overall survival (P < 0.05). miR-125b overexpression significantly promoted tumor cell behaviors and increased PI3K/mTOR phosphorylation (P < 0.05); while inhibiting miR-125b expression significantly inhibited tumor cell biological behaviors, and decreased PI3K/mTOR phosphorylation (P < 0.05). miR-125b level is increased in OSCC tumor tissues, which is related to clinicopathological characteristics. miR-125b overexpression promotes OSCC cell behaviors by regulating PI3K/mTOR signaling.

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.

Relationship Between mir15b and Sal-Like Protein 4 and Biological Behavior of Oral Squamous Cell Carcinoma

miR15b and SALL4 are involved in a variety of tumor progression. The roles of miR15b and SALL4 in oral squamous cell carcinoma (OSCC) remains unclear. The tumors and normal mucosa of OSCC patients were collected to detect miR15b and SALL4 level by Real-time PCR and analyze their correlation with OSCC clinicopathological features. Oral cancer Tca8113 cells were separated into control group; miR15b mimics group and miR15b inhibitor group followed by analysis of SALL4 expression, cell survival by MTT assay; cell invasion by Transwell chamber assay, as well as expression of N-cadherin and Vimentin and correlated with TNM stage, tumor volume and metastasis, and positively with differentiation TGF-β by Western blot. miR15b expression was decreased and SALL4 expression was increased in OSCC tumor tissues. miR15b was negatively degree (P < 0.05), whereas, opposite correlation of SALL4 with the above parameters was found (P < 0.05). miR15b and SALL4 were negatively correlated. MiR15b mimics significantly up-regulated MiR15b, decreased SALL4 expression, inhibited Tca8113 cell proliferation and invasion, as well as reduced N-cadherin, Vimentin and TGF-βexpression (P < 0.05). Opposite results were found in MiR15b inhibitor group. MiR15b expression is decreased and SALL 4 is increased in OSCC tumor tissues. MiR15b and SALL4 is closely related to OSCC clinicopathological features. MiR15b regulates the expression of EMT-related genes and TGF-β, thereby altering the proliferation and invasion of OSCC cells.