Alcohol intake and oral cavity cancer risk among men in a prospective study in Kerala, India

Association of KMT2C Genetic Variants with the Clinicopathologic Development of Oral Cancer

Lysine methyltransferase 2C (KMT2C) is a tumor-suppressor gene in several myeloid cells and epithelia and is linked with blood and solid tumor cancers. KMT2C single-nucleotide polymorphisms (SNPs) are also connected with several cancer types. Our study aimed to explore the potential genetic polymorphisms of KMT2C in oral cancer. Five KMT2C SNPs, including rs201834857, rs4725443, rs6464221, rs74483926, and rs6943984, were evaluated in 284 cancer-free controls and 284 oral squamous cell carcinoma (OSCC) cases. We found that individuals with the TC genotype or TC + CC genotype of rs4725443 had a higher risk of oral cancer incidence than those with the TT genotype. Further analysis of KMT2C SNP rs4725443 revealed that the TC + CC genotype of rs4725443 was associated with a significantly advanced tumor stage in the non-alcohol-drinking population. Moreover, the TC + CC genotype of rs4725443 was connected with poor cell differentiation in the alcohol-drinking population. Through analyzing a dataset from The Cancer Genome Atlas (TCGA), we found that reduced KMT2C levels were associated with advanced tumor stage, lymph node invasion, and poor cell differentiation in head and neck squamous cell carcinomas. Our data suggest that KMT2C SNP rs4725443 is a potential genetic marker for oral cancer patients in both non-alcohol-drinking and alcohol-drinking populations.

Oral Cavity Cancer in the Indian Subcontinent - Challenges and Opportunities

Oral cavity cancer (OCC) poses a global challenge that plagues both the Orient and the Occident, accounting for an estimated 350 000 new cases and 177 000 deaths in 2018. OCC is a major public health problem in the Indian subcontinent, where it ranks among the top three cancer types in both incidence and mortality. Major risk factors are the use of tobacco, betel quid and alcohol consumption. OCC is a heterogeneous group of multiple histologies that affects multiple subsites. The oral cavity includes the lips, buccal mucosa, teeth, gingiva, anterior two-thirds of the tongue, floor of the mouth and hard palate. OCC is defined as cancer of lips, mouth and tongue as defined by the International Classification of Diseases coding scheme. The epidemiology, aetio-pathogenesis and treatment philosophy are similar within this group. Although salivary gland malignancies, sarcomas, mucosal melanomas and lymphomas can also arise within the oral cavity, this review will focus on squamous cell cancer, which is the predominant histology in OCC. We review and contrast data from developing and developed countries. We also highlight the unique regional challenges that countries in the East face; citing India as an example, we elaborate on the opportunities and scope for improvement in the management of OCC.

Evaluation of the Prevalence of Oral Mucosal Lesions in a Population of Eastern Coast of South India

Objective/Aim

The aim of this study is to measure the association between oral mucosal lesions (OMLs) and habit of tobacco and alcohol in the population of Guntur city, Andhra Pradesh, South India.

Material and Method

A cross-sectional study was conducted on 300 participants in Guntur city with the habit of tobacco and alcohol consumption in various forms who were selected by stratified cluster random sampling technique. Guntur city was divided into four zones, that is, North, East, South, and West; and two administrative wards were randomly selected from each zone as clusters. Information was obtained by interviewing the participant regarding various tobacco-related habits followed by standardized clinical examination in the field. Clinical data were collected using a modified 1980 WHO Pro forma where the basis for diagnosis was established as per the criteria provided by the epidemiology guide for the diagnosis of oral mucosal diseases (WHO). Statistical tests such as Pearson Chi-square were exercised to test the significance, using SPSS version 19.0 with 0.05 as cutoff level of significance.

Results

Overall oral soft-tissue lesions were found in 42.4% of the study participants including nicotinic stomatitis, tobacco pouch keratosis, smokers melanosis, mild keratosis of the palate, and chewer's mucosa. In this study, nicotinic stomatitis was found to be the most common soft-tissue lesion among men, while leukoplakia was found to be the most common premalignant lesion with the prevalence being 5.7%. While oral submucous fibrosis was found to be the most common premalignant condition among women. It was found that 13.2% of illiterates (53) were having leukoplakia. In the present study, the lower labial mucosa and buccal mucosa were found to be the most common sites of occurrence of leukoplakia and oral submucous fibrosis.

Conclusion

This study gives information on the association of OML in smokers, chewers, alcoholics, and those with mixed habits. This study highlighted six habit-related OML which included potentially malignant disorders such as leukoplakia and oral submucous fibrosis. Future case-control or cohort studies for individual lesions and with larger sample size are necessary to evaluate the risk for OML including potentially malignant conditions and oral cancer resulting from smoking and chewing habits.

Cell division cycle associated 1 as a novel prognostic biomarker and therapeutic target for oral cancer

Oral cavity carcinoma (OCC) is one of the most common causes of cancer-related death worldwide and has poor clinical outcome after standard therapies. Therefore, new prognostic biomarkers and therapeutic targets for OCC are urgently needed. We selected cell division cycle associated 1 (CDCA1) as a candidate OCC biomarker. Immunohistochemical analysis confirmed that CDCA1 protein was expressed in 67 of 99 OCC tissues (67.7%), but not in healthy oral epithelia. CDCA1 expression was significantly associated with poor prognosis in OCC patients (P=0.0244). Knockdown of CDCA1 by siRNAs significantly increased apoptosis of tumor cells. These data suggest that CDCA1 represents a novel prognostic biomarker and therapeutic target for OCC.

The impact of low-dose carcinogens and environmental disruptors on tissue invasion and metastasis

The purpose of this review is to stimulate new ideas regarding low-dose environmental mixtures and carcinogens and their potential to promote invasion and metastasis. Whereas a number of chapters in this review are devoted to the role of low-dose environmental mixtures and carcinogens in the promotion of invasion and metastasis in specific tumors such as breast and prostate, the overarching theme is the role of low-dose carcinogens in the progression of cancer stem cells. It is becoming clearer that cancer stem cells in a tumor are the ones that assume invasive properties and colonize distant organs. Therefore, low-dose contaminants that trigger epithelial-mesenchymal transition, for example, in these cells are of particular interest in this review. This we hope will lead to the collaboration between scientists who have dedicated their professional life to the study of carcinogens and those whose interests are exclusively in the arena of tissue invasion and metastasis.

Epidemiology of oral cancer in Asia in the past decade--an update (2000-2012)

The prevalence of oral cancers (OC) is high in Asian countries, especially in South and Southeast Asia. Asian distinct cultural practices such as betel-quid chewing, and varying patterns of tobacco and alcohol use are important risk factors that predispose to cancer of the oral cavity. The aim of this review is to provide an update on epidemiology of OC between 2000 and 2012. A literature search for this review was conducted on Medline for articles on OC from Asian countries. Some of the articles were also hand searched using Google. High incidence rates were reported from developing nations like India, Pakistan, Bangladesh, Taiwan and Sri Lanka. While an increasing trend has been observed in Pakistan, Taiwan and Thailand, a decreasing trend is seen in Philippines and Sri Lanka. The mean age of occurrence of cancer in different parts of oral cavity is usually between 51-55 years in most countries. The tongue is the leading site among oral cancers in India. The next most common sites in Asian countries include the buccal mucosa and gingiva. The 5 year survival rate has been low for OC, despite improvements in diagnosis and treatment. Tobacco chewing, smoking and alcohol are the main reasons for the increasing incidence rates. Low socioeconomic status and diet low in nutritional value lacking vegetables and fruits contribute towards the risk. In addition, viral infections, such as HPV and poor oral hygiene, are other important risk factors. Hence, it is important to control OC by screening for early diagnosis and controlling tobacco and alcohol use. It is also necessary to have cancer surveillance at the national-level to collect and utilise data for cancer prevention and control programs.

Chromosomal damage and apoptosis analysis in exfoliated oral epithelial cells from mouthwash and alcohol users

Chromosomal damage and apoptosis were analyzed in users of mouthwash and/or alcoholic beverages, using the micronucleus test on exfoliated oral mucosa cells. Samples from four groups of 20 individuals each were analyzed: three exposed groups (EG1, EG2 and EG3) and a control group (CG). EG1 comprised mouthwash users; EG2 comprised drinkers, and EG3 users of both mouthwashes and alcoholic beverages. Cell material was collected by gently scraping the insides of the cheeks. Then the cells were fixed in a methanol/acetic acid (3:1) solution and stained and counterstained, respectively, with Schiff reactive and fast green. Endpoints were computed on 2,000 cells in a blind test. Statistical analysis showed that chromosomal damage and apoptosis were significantly higher in individuals of groups EG1 and EG3 than in controls (p < 0.005 and p < 0.001, respectively). No significant difference in chromosomal damage and apoptosis was observed between the exposed groups. In EG2, only the occurrence of apoptosis was significantly higher than in the controls. These results suggest that mouthwashes alone or in association with alcoholic drinks induce genotoxic effects, manifested as chromosomal damage and apoptosis. They also suggest that alcoholic drinks are effective for stimulating the process of apoptosis. However, these data need to be confirmed in larger samples.

Genetic variants in nicotine addiction and alcohol metabolism genes, oral cancer risk and the propensity to smoke and drink alcohol: a replication study in India

BACKGROUND

Genetic variants in nicotinic acetylcholine receptor and alcohol metabolism genes have been associated with propensity to smoke tobacco and drink alcohol, respectively, and also implicated in genetic susceptibility to head and neck cancer. In addition to smoking and alcohol, tobacco chewing is an important oral cancer risk factor in India. It is not known if these genetic variants influence propensity or oral cancer susceptibility in the context of this distinct etiology.

METHODS

We examined 639 oral and pharyngeal cancer cases and 791 controls from two case-control studies conducted in India. We investigated six variants known to influence nicotine addiction or alcohol metabolism, including rs16969968 (CHRNA5), rs578776 (CHRNA3), rs1229984 (ADH1B), rs698 (ADH1C), rs1573496 (ADH7), and rs4767364 (ALDH2).

RESULTS

The CHRN variants were associated with the number of chewing events per day, including in those who chewed tobacco but never smoked (P =  0.003, P =  0.01 for rs16969968 and rs578776 respectively). Presence of the variant allele contributed to approximately 13% difference in chewing frequency compared to non-carriers. While no association was observed between rs16969968 and oral cancer risk (OR =  1.01, 95% CI =  0.83- 1.22), rs578776 was modestly associated with a 16% decreased risk of oral cancer (OR =  0.84, 95% CI =  0.72- 0.98). There was little evidence for association between polymorphisms in genes encoding alcohol metabolism and oral cancer in this population.

CONCLUSION

The association between rs16969968 and number of chewing events implies that the effect on smoking propensity conferred by this gene variant extends to the use of smokeless tobacco.

Tobacco smoking, alcohol drinking and risk of oral cavity cancer by subsite: results of a French population-based case-control study, the ICARE study

The objective was to examine the role of tobacco smoking and alcohol drinking in the incidence of oral cavity cancer by subsite in France, a high-incidence area. We analysed detailed data on lifelong tobacco smoking and alcohol drinking from 772 oral cavity cancer cases and 3555 controls included in a population-based case-control study, the ICARE study. Tobacco smoking increased the risk of oral cavity cancer even for the smaller quantities and durations, whereas alcohol drinking increased this risk only in heavy drinkers who were also ever smokers. The combined effect of smoking and drinking was greater than multiplicative. The floor of the mouth was the subsite that was the most affected by the harmful effects of tobacco and alcohol, whereas the gums were less susceptible. The risk associated with tobacco and alcohol consumption did not differ between intraoral cavity and subsites usually included in the oropharynx (soft palate and base of the tongue). Population-attributable risks for oral cavity cancer were 78.6% for tobacco smoking, 7.3% for alcohol drinking and 80.7% for tobacco and/or alcohol consumption. These results indicate that regular oral check-ups should be targeted at smokers and heavy drinkers, and that prevention efforts should be focused on smoking cessation.

Oral and pharyngeal cancer in women

Although in the United States the incidence of oral and pharyngeal cancer (OPC) has been significantly higher in men than in women, the identification of human papilloma virus as a risk factor for OPC has focused new scrutiny on who may develop OPC. One surprising element is that non-Hispanic white women have a higher incidence of OPC than of cervical cancer. OPC is thus a woman's disease, and diligence is needed to ensure that the occurrence of OPC in women does not go undetected by their oral health care providers.

Elevated plasma level of visfatin/pre-b cell colony-enhancing factor in male oral squamous cell carcinoma patients

Objectives: Visfatin, also known as nicotiamide phosphoribosyltransferase or pre-B cell colony enhancing factor, is a pro-inflammatory cytokine whose serum level is increased in various cancers. In this study, we investigated whether plasma visfatin levels were altered in patients with oral squamous cell carcinoma (OSCC). The relationship between plasma visfatin levels and the pretreatment hematologic profile was also explored. Study Design: Plasma visfatin concentrations were measured through ELISA in OSCC patients and control subjects. A total of 51 patients with OSCC and 57 age- and body mass index (BMI)-matched control subjects were studied. All study subjects were male. Results: Plasma visfatin was found to be elevated in patients with OSCC (7.0 ± 4.5 vs. 4.8 ± 1.9 ng/ml, p = 0.002). Multiple logistic regression analysis revealed visfatin as an independent association factor for OSCC, even after full adjustment of known biomarkers. Visfatin level was significantly correlated with white blood cell (WBC) count, neutrophil count, and hematocrit (all p < 0.05). In addition, WBC count, neutrophil count, and visfatin gradually increased with stage progression, and hematocrit gradually decreased with stage progression (all p < 0.05). Conclusion: Increased plasma visfatin levels were associated with OSCC, independent of risk factors, and were correlated with inflammatory biomarkers. These data suggest that visfatin may act through inflammatory reactions to play an important role in the pathogenesis of OSCC.

Key words:Visfatin; oral squamous cell carcinomas; white blood cell count; neutrophil count.

Identification of novel tumor markers for oral squamous cell carcinoma using glycoproteomic analysis

BACKGROUND

Oral cancer, the largest subset of head and neck cancer, has become one of the most lethal malignancies during the last two decades. Although several diagnostic tools have been applied for the early detection of oral malignancies, it is still urgent to identify novel tumor markers. In this study, we explored the cell surface N-glycomes of primary cultured human oral keratinocytes (HOK), immortalized human gingival keratinocytes (SG cells), and oral squamous cell carcinoma (OC2).

METHODS

Enzymatically hydrolyzed cell surface N-glycans were analyzed by MALDI-TOF mass spectrometry.

RESULTS

High levels of fucosylated N-glycans, especially core-fucosylated N-glycans, were observed on the OC2 cell surface whereas the major N-glycans on SG and HOK cells were high mannose type. In addition, the mRNA expression level of fucosyltransferase 8 was elevated significantly in OC2 cells than in SG and HOK cells. Core-fucosylated glycoproteins of OC2 cells were then purified with lectin affinity chromatography and a key adhesion molecule in cancer cells, CD147, was identified. Finally, overexpression of cell surface CD147 was confirmed on OC2 cells and oral cancer tissues (tissue array).

CONCLUSIONS

CD147 was discovered by glycoproteomic approaches and suggested to be a potential novel tumor marker for oral cancer diagnosis.

Challenges of the oral cancer burden in India

Oral cancer ranks in the top three of all cancers in India, which accounts for over thirty per cent of all cancers reported in the country and oral cancer control is quickly becoming a global health priority. This paper provides a synopsis of the incidence of oral cancer in India by focusing on its measurement in cancer registries across the country. Based on the International Classification of Disease case definition adopted by the World Health Organisation, and the International Agency for Research on Cancer, this review systematically examines primary and secondary data where the incidence or prevalence of oral cancer is known to be directly reported. Variability in age-adjusted incidence with crude incidence is projected to increase by 2030. Challenges focus on measurement of disease incidence and disease-specific risk behavior, predominantly, alcohol, and tobacco use. Future research should be aimed at improving quality of data for early detection and prevention of oral cancer.

A review of risk factors for oral cavity cancer: the importance of a standardized case definition

The aim of this work is to review the literature on risk factors of oral cavity cancer with a special attention to the definition of the cases, in order to highlight special features of these cancers and of their subsites. PubMed database was systematically searched to access relevant articles published between 1980 and 2010. Reference lists of selected papers were examined to identify further articles. One hundred and two studies met the inclusion criteria. Their results were difficult to compare because of the lack of uniformity in defining oral cavity. In addition, few studies examined risk factors other than alcohol and tobacco, and studies differentiating between subsites were rare. Despite these limitations, some characteristics of oral cavity cancers may be emphasized: smoked tobacco seems to be a stronger risk factor for oral cavity cancer than alcohol, and the floor of the mouth seems to be more sensitive to the harmful effects of alcohol and smoked tobacco. Studies limited strictly to oral cavity cancers and distinguishing between subsites are needed to better understand the aetiology of these cancers, and better define risk groups to target prevention efforts and screening.

A novel molecular signature identified by systems genetics approach predicts prognosis in oral squamous cell carcinoma

Molecular methods for predicting prognosis in patients with oral cavity squamous cell carcinoma (OSCC) are urgently needed, considering its high recurrence rate and tendency for metastasis. The present study investigated the genetic basis of variations in gene expression associated with poor prognosis in OSCC using Affymetrix SNP 6.0 and Affymetrix GeneChip Human Gene 1.0 ST arrays. We identified recurrent DNA amplifications scattered from 8q22.2 to 8q24.3 in 112 OSCC specimens. These amplicons demonstrated significant associations with increased incidence of extracapsular spread, development of second primary malignancies, and poor survival. Fluorescence in situ hybridization, in a validation panel consisting of 295 cases, confirmed these associations. Assessment of the effects of copy number variations (CNVs) on genome-wide variations in gene expression identified a total of 85 CNV-associated transcripts enriched in the MYC-centered regulatory network. Twenty-four transcripts associated with increased risk of second primary malignancies, tumor relapse, and poor survival. Besides MYC itself, a novel dysregulated MYC module plays a key role in OSCC carcinogenesis. This study identified a candidate molecular signature associated with poor prognosis in OSCC patients, which may ultimately facilitate patient-tailored selection of therapeutic strategies.

Epidemiology of cancer from the oral cavity and oropharynx

The classification of sites in tumors of the oral cavity, oropharynx, pharynx, and hypopharynx varies in the literature. More than 90% of these tumors of the mucosal lining are classified as squamous cell carcinoma developed from premalignant lesions such as leukoplakia and erythroleukoplakia. These carcinomas are associated to environmental and lifestyle risk factors, among which tobacco and alcohol play a major role. In addition to tobacco smoking, tobacco chewing is another risk factor as well as chewing betel quid and areca nut in Asia. Certain strains of virus, such as the sexually transmitted human papilloma virus, also play a carcinogenetic role. The temporal trends in incidence of these tumors relate to environmental factors; there is an increase in tendency in countries without prevention and a decrease in countries having an active policy of prevention of alcohol and tobacco consumption. In contrast, an increased incidence occurs in the world at tumor sites related to human papilloma virus infection in relation to changes in sexual habits.

Comparing dentists' and the public's awareness about oral cancer in a community-based study in Northern Germany

INTRODUCTION

The purpose of the study was to compare the knowledge about oral cancer of dentists and the public using a standardised, internationally accepted questionnaire in Schleswig-Holstein, Germany.

MATERIAL AND METHODS

In November 2007, a standardised questionnaire about knowledge on oral cancer was mailed to all dentists within the state (n=2233). Simultaneously, a polling firm conducted a representative survey with a shortened version of the questionnaire, via computer-aided telephone interview, among the public (n=1000).

RESULTS

The results are based on 306 usable dental questionnaires (n=14%) and 1000 interviews of the population. Most of the diagnostic factors were correctly identified by the dentists, whereas less than 30% of the public knew these factors. Only 47% of the dentists and 27% of the public were aware that the patient is asymptomatic in the early stage of oral cancer. The knowledge about risk factors was inconsistent and showed deficits by the dentists as well as by the public.

CONCLUSIONS

The survey revealed a few gaps in dentists' knowledge compared to large deficits in the public's knowledge about oral cancer. Based on these results, a continuing educational programme for the dentists as well as an educational campaign for the public should be pursued.

Spatiotemporal trends in oral cancer mortality and potential risks associated with heavy metal content in Taiwan soil

Central and Eastern Taiwan have alarmingly high oral cancer (OC) mortality rates, however, the effect of lifestyle factors such as betel chewing cannot fully explain the observed high-risk. Elevated concentrations of heavy metals in the soil reflect somewhat the levels of exposure to the human body, which may promote cancer development in local residents. This study assesses the space-time distribution of OC mortality in Taiwan, and its association with prime factors leading to soil heavy metal content. The current research obtained OC mortality data from the Atlas of Cancer Mortality in Taiwan, 1972-2001, and derived soil heavy metals content data from a nationwide survey carried out by ROCEPA in 1985. The exploratory data analyses showed that OC mortality rates in both genders had high spatial autocorrelation (Moran's I = 0.6716 and 0.6318 for males and females). Factor analyses revealed three common factors (CFs) representing the major pattern of soil pollution in Taiwan. The results for Spatial Lag Models (SLM) showed that CF1 (Cr, Cu, Ni, and Zn) was most spatially related to male OC mortality which implicates that some metals in CF1 might play as promoters in OC etiology.

Alcohol-folate interactions in the risk of oral cancer in women: a prospective cohort study

BACKGROUND

The aim of this cohort study was to quantify the effect of alcohol on the risk of oral cancer in different strata of folate intake, controlling for known confounders.

METHODS

A cohort of 87,621 women in the Nurses' Health Study was followed up from 1980 to 2006, and 147 incident oral cancer cases were reported and confirmed. Data on alcohol intake and diet were obtained through self-reported food frequency questionnaires every 4 years. Cox proportional regression analysis was conducted to estimate the adjusted risk ratios (RR) and 95% confidence intervals (95% CI).

RESULTS

When compared with nondrinkers, the adjusted RRs (95% CIs) for alcohol intake were 0.59 (0.39-0.87) for 0.1-14.9 g/d, 1.15 (0.67-1.97) for 15-29.9 g/d, and 1.92 (1.08-3.40) for ≥30 g/d. We observed a significant interaction between alcohol and folate intakes (P = 0.02). The cancer risk for subjects with high alcohol (≥30 g/d) and low folate (<350 μg/d) intakes was significantly elevated (RR, 3.36; 95% CI, 1.57-7.20) as compared with nondrinkers with low folate intake. The risk associated with high alcohol intake (≥30 g/d) was reduced to 0.98 (0.35-2.70) in the high-folate (≥350 μg/d) group as compared with nondrinkers with high folate intake.

CONCLUSIONS

High alcohol intake is associated with significantly increased oral cancer risk, especially in women with low folate intake.

IMPACT

A significant interaction between alcohol and folate intakes seems to affect oral cancer risk in women, a finding with potential public health utility.

Oral microbiota and cancer

Inflammation caused by infections may be the most important preventable cause of cancer in general. However, in the oral cavity the role of microbiota in carcinogenesis is not known. Microbial populations on mouth mucosa differ between healthy and malignant sites and certain oral bacterial species have been linked with malignancies but the evidence is still weak in this respect. Nevertheless, oral microorganisms inevitably up-regulate cytokines and other inflammatory mediators that affect the complex metabolic pathways and may thus be involved in carcinogenesis. Poor oral health associates statistically with prevalence of many types of cancer, such as pancreatic and gastrointestinal cancer. Furthermore, several oral micro-organisms are capable of converting alcohol to carcinogenic acetaldehyde which also may partly explain the known association between heavy drinking, smoking, poor oral health and the prevalence of oral and upper gastrointestinal cancer. A different problem is the cancer treatment-caused alterations in oral microbiota which may lead to the emergence of potential pathogens and subsequent other systemic health problems to the patients. Hence clinical guidelines and recommendations have been presented to control oral microbiota in patients with malignant disease, but also in this area the scientific evidence is weak. More controlled studies are needed for further conclusion.