High serum level of retinol and α-tocopherol affords protection against oral cancer in a multiethnic population

The role of blood metabolites in oral cancer: insights from a Mendelian randomization approach

Aim

This research aimed to explore the causal impact of blood metabolites on oral cancer using a two-sample Mendelian randomization (MR) analysis. The study endeavored to identify potential biomarkers for oral cancer's clinical management.

Materials and methods

Based on the large individual-level datasets from UK Biobank as well as GWAS summary datasets, we first constructed genetic risk scores (GRSs) of 486 human blood metabolites and evaluated the effect on oral cancer. Various statistical methods, including inverse variance weighted (IVW), MR-Egger, and weighted median, among others, were employed to analyze the potential causal relationship between blood metabolites and oral cancer. The sensitivity analyses were conducted using Cochran's Q tests, funnel plots, leave-one-out analyses, and MR-Egger intercept tests.

Results

29 metabolites met the stringent selection criteria. Out of these, 14 metabolites demonstrated a positive association with oral cancer risk, while 15 metabolites indicated a protective effect against oral cancer. The IVW-derived estimates were significant, and the results were consistent across different statistical methodologies. Both the Cochran Q test and the MR-Egger intercept test indicated no heterogeneity and pleiotropy.

Conclusion

This MR study offers evidence of the role specific blood metabolites play in oral cancer, pinpointing several with potential risk or protective effects. These findings could be helpful for new diagnostic tools and treatments for oral cancer. While the results are promising, additional research is necessary to fully validate and refine these conclusions. This study serves as a foundational step towards more comprehensive understandings in the future.

Biobanking in dentistry: A review

Biobanks are not-for-profit services for the collection, processing, storage and distribution of biological samples and data for research and diagnostic purposes. In dentistry, biological materials and data obtained from questionnaires investigating oral conditions can be stored and used for large-scale studies on oral and systemic diseases. To give some examples: gene expression microarrays obtained on biobanked specimens were used in the identification of genetic alterations in oral cancer; efforts to identify genetic mechanisms behind dental caries have been based on an integrative analysis of transcriptome-wide associations and messenger RNA expression. One of the largest studies on facial pain was conducted using Biobank data. Cryopreservation of dental pulp stem cells is a common practice in tooth biobanks. With the exception of teeth and pulp, also leftover oral soft and hard tissues may represent a source of healthy samples that has rarely been exploited as yet. While biobanks are increasingly attracting the attention of the scientific community and becoming economically sustainable, a systematic approach to this resource in dentistry seems to be lacking. This review illustrates the applications of biobanking in dentistry, describing biobanked pathological and healthy samples and data, and discussing future developments.

The Association between Dietary Total Antioxidant Capacity and Glioma in Adults

OBJECTIVE

We assessed the relation between dietary total antioxidant capacity (TAC) and risk of glioma among Iranian adults. Design: A hospital-based case-control study. Setting: This case-control investigation was done in 2011. Usual dietary intakes of participants during the preceding year were examined using a food frequency questionnaire. Data on dietary TAC from foods was gathered from published databases that provided the antioxidant capacity for each food item, measured by ferric reducing antioxidant power. Participants: Cases were individuals with pathologically confirmed glioma that were diagnosed during the last month (n = 128). Controls were individuals, aged between 20 and 75 years, who were hospitalized or were outpatients referred to other wards of the same hospitals (n = 256). Results: Compared with participants in the lowest quartile, those in the highest quartile of dietary TAC had a lower odds of glioma (OR: 0.28, 95%CI: 0.15-0.45). This association was strengthened when potential confounders were taken into account (OR: 0.13; 95%CI: 0.05-0.35). Such inverse association was also seen for men (OR: 0.05, 95%CI: 0.01-0.19), but not for women. Furthermore, significant inverse associations were seen between dietary intakes of vitamin C (OR for Q₄ vs. Q₁: 0.14, 95%CI: 0.05-0.36; P-trend < 0.01), vitamin B6 (OR for Q₄ vs. Q₁: 0.35, 95%CI: 0.13-0.97; P-trend = 0.02) and β-carotene (OR for Q₃ vs. Q₁: 0.43, 95%CI: 0.19-0.98; P-trend = 0.57) and glioma, after controlling for potential covariates. Conclusions: We found that dietary TAC as well as dietary intake of vitamin C, vitamin B6, and β-carotene was inversely associated with odds of glioma in adults.

COMPARISON OF EXPRESSION OF E-CADHERIN IN ORAL PSEUDOEPITHELIOMATOUS HYPERPLASIA AND ORAL SQUAMOUS CELL CARCINOMA

Background: Pseudo-epitheliomatous Hyperplasia (PEH) is a benign proliferation of epithelium occurring in response to various neoplastic lesions, infections and inflammatory processes. It can be mistaken especially in small biopsies for an invasive oral squamous cell carcinoma (OSCC). The objective of this study was to determine the expression and comparison of immunohistochemical marker E-cadherin in OSCC and PEH lesions. Materials & Methods: This cross-sectional study was conducted in Department of Histopathology, Armed Forces Institute of Pathology, Rawalpindi, Pakistan from January 2013 to March 2016. 60 paraffin embedded cases, 30 each of PEH and OSCC were retrieved and stained with haematoxylin and eosin. They were then immune-stained with E-cadherin and expression evaluated and compared in two lesions by histopathologist. Age, sex, site of lesion and E-cadherin expression were variables. Age was described by mean and SD and other variables as frequency and percentages. Results: Mean age of OSCC group was 60.1±17.3 years and PEH group 52.7±16.6 years. OSCC group included 16 (53.33%) men and 14 (46.67%) women. PEH group included 18 (60%) men and 12 (40%) women. In OSCC group, site of lesion was buccal mucosa 12 (40%) cases, gingiva 10 (33.3%), tongue 7 (23.3%) and floor of mouth 1 (3.4%) case. In PEH group, site of lesion was buccal mucosa 12 (40%) cases, tongue 11 (36.67%), gingiva 6 (20%) and palate 1 (3.3%) case. The expression of E-cadherin was negative in all 30 cases of OSCC and positive in 29/30 (96.67%) cases in PEH. Conclusion: E-cadherin can be used as an ancillary marker in the differentiation of oral squamous cell carcinoma and pseudo-epitheliomatous hyperplasia.

Serum Retinol and Risk of Overall and Site-Specific Cancer in the ATBC Study

Retinol, the most biologically active form of vitamin A, might influence cancer-related biological pathways. However, results from observational studies of serum retinol and cancer risk have been mixed. We prospectively examined serum retinol and risk of overall and site-specific cancer in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (n = 29,104 men), conducted in 1985-1993, with follow-up through 2012. Serum retinol concentration was measured using reverse-phase high-performance liquid chromatography. Cox proportional hazards models estimated the association between baseline serum retinol quintile and overall and site-specific cancer risk in 10,789 cases. After multivariable adjustment, higher serum retinol was not associated with overall cancer risk (highest vs. lowest quintile: hazard ratio (HR) = 0.97, 95% confidence interval (CI): 0.91, 1.03; P for trend = 0.43). Higher retinol concentrations were, however, associated with increased risk of prostate cancer (highest vs. lowest quintile: HR = 1.28, 95% CI: 1.13, 1.45; P for trend < 0.0001) and lower risk of both liver and lung cancers (highest vs. lowest quintile: for liver, HR = 0.62, 95% CI: 0.42, 0.91; P for trend = 0.004; and for lung, HR = 0.80, 95% CI: 0.72, 0.88; P for trend < 0.0001). No associations with other cancers were observed. Understanding the mechanisms that underlie these associations might provide insight into the role of vitamin A in cancer etiology.

The risks of ubiquinone and β-carotene deficiency and metabolic disorders in patients with oral cancer

Background

Cancer development is mediated by oxidative stress and inflammation, which may correlate with metabolic disorders. The aim of this study was to evaluate antioxidant vitamins status and metabolic parameters in patients with oral cancer according to tumor-node-metastasis (TNM) stages.

Methods

A total of 194 patients with oral cancer were enrolled in this study. The patients were stratified for four groups according to cancer stages and that the statistics are comparisons across these groups. The levels of antioxidant vitamins (ubiquinone, β-carotene, vitamin A and E), metabolic parameters, oxidative stress, antioxidant enzymes activity, and inflammatory markers were measured.

Results

More than half of the subjects had high blood pressure, central obesity, hyperglycemia, and hyperlipidemia regardless of TNM stage. With regard to antioxidant vitamins status, 46 and 94% of patients had β-carotene and ubiquinone deficiency, respectively. Patients in T3 and T4 stages had significantly lower antioxidant enzyme (catalase, p = 0.03) activity and higher inflammatory markers levels (high sensitivity C-reactive protein and interleukin-6, p < 0.01) than patients in the other stages. In addition, the level of β-carotene was negatively associated with waist circumference, and ubiquinone was positively associated with the level of high-density lipoprotein cholesterol (p < 0.05). Higher β-carotene and ubiquinone levels were negatively associated with hypertriglyceridemia and the risk of metabolic syndrome (p < 0.05).

Conclusions

A high proportion of patients with oral cancer had ubiquinone or β-carotene deficiency and metabolic disorders. The level of ubiquinone or β-carotene was negatively associated with the risk of central obesity, hypertriglyceridemia, and metabolic syndrome. Since patients with oral cancer suffer from high oxidative stress and inflammation (particularly in the T3 and T4 stages), supplementation with antioxidant vitamins such as ubiquinone or β-carotene could be preferentially applied.

Exploratory Study to Evaluate Changes in Serum Lipid Levels as Early Diagnostic and/or Prognostic Indicators for Oral Submucous Fibrosis and Cancer among Gutkha Consumers in India

BACKGROUND

In India smokeless tobacco users account for 25.9% of total tobacco use, Gutkha being the most common form. This study evaluated the association between serum lipid profile and Gutkha use as an early diagnostic and/or prognostic indicator for oral submucous fibrosis (OSMF) and oral cancer (Oral Ca) in non-smokers and non-alcohol consumers.

MATERIALS AND METHODS

A total of 163 participants were recruited from two sites in India. Participants were divided into four groups: individuals without any Gutkha chewing habit and without any oral lesions (control group), individuals with Gutkha chewing habit but without any oral lesions (GWL), patients with a confirmed clinical diagnosis of OSMF, and patients with a confirmed diagnosis of Oral Ca. Mixed linear modelling (MLM) was conducted to detect the change in mean serum lipid levels among four groups.

RESULTS

The sample consisted of 69% males and 31% females. Results of MLM show an inverse relationship between serum lipid levels in OSMF, and Oral Ca groups when compared to the control group.

CONCLUSIONS

The results of our study demonstrated that GWL, OSMF and Oral Ca patients had lower serum lipid levels. Low serum lipid levels could be an indicator of initial neoplastic changes in oral cancer.

Alcohol Drinking Obliterates the Inverse Association Between Serum Retinol and Risk of Head and Neck Cancer

This analysis evaluated the association between serum retinol levels and risk of head and neck cancer (HNC) and whether the association is modulated by the use of alcohol, betel quid, or cigarette. In addition, we also examined the association between HNC risk and 2 single nucleotide polymorphisms, TTR rs1667255 and RBP4 rs10882272, that have been associated with serum retinol levels. Unconditional logistic regression was performed to evaluate the association between serum retinol levels and HNC risk among 160 HNC cases and 198 controls. The associations between TTR rs1667255 and RBP4 rs10882272 and serum retinol levels or HNC risk were evaluated by linear regression and unconditional logistic regression, respectively, for 418 HNC cases and 497 controls. The results showed that HNC cases had a lower mean serum retinol level compared with controls (845.3 μg/L vs 914.8 μg/L, P = 0.03). An inverse association between serum retinol levels and HNC risk occurred among never/occasional alcohol drinkers but not among regular drinkers. TTR rs1667255 was associated with serum retinol levels; however, neither TTR rs1667255 nor RBP4 rs10882272 was associated with HNC risk. In summary, this study showed an inverse association between serum retinol levels and HNC risk, specifically among never/occasional alcohol drinkers. More studies are needed to establish the underlying biologic mechanisms for the inverse association between serum retinol levels and HNC risk and the modulation of this relationship by alcohol drinking.