Alert for an epidemic of oral cancer due to use of the betel quid substitutes gutkha and pan masala: a review of agents and causative mechanisms

Oral cancer in India continues in epidemic proportions: evidence base and policy initiatives

OBJECTIVES

India has the highest number of cases of oral cancer in the world and this is increasing. This burden is not fully appreciated even within India, despite the high incidence and poor survival associated with this disease. Because the aetiology of oral cancer is predominantly tobacco-related, the immense public health challenge can be ameliorated through habit intervention.

METHODS

We reviewed current rates of incidence, mortality and survival, and investigated the determinants of disease and current prevention strategies.

RESULTS

In addition to tobacco smoking and the myriad other forms of tobacco use prevalent in India, risk factors include areca nut consumption, alcohol consumption, human papillomavirus, increasing age, male gender and socioeconomic factors. Although India has world-leading cancer treatment centres, access to these is limited. Further, the focus of health care services remains clinical and is either curative or palliative.

CONCLUSIONS

Although the efforts of agencies such as the Ministry of Health and Family Welfare and the Indian Dental Association are laudable, enhanced strategies should be based on common risk factors, focusing on primary prevention, health education, early detection and the earliest possible therapeutic intervention. A multi-agency approach is required.

Oral submucous fibrosis: an overview of the aetiology, pathogenesis, classification, and principles of management

Oral submucous fibrosis (OSMF) is a complex, debilitating, and precancerous condition. Formerly confined to the Indian subcontinent, it is now often seen in the Asian populations of the United Kingdom, USA, and other developed countries, and is therefore a serious problem for global health. The well-known causative agent of the disease, areca-nut is now recognised as a group one carcinogen. We review and discuss all components of OSMF, including the terminology, presentation, aetiology, and pathogenesis, and provide a brief overview of its management.

Panmasala chewing induces deterioration in oral health and its implications in carcinogenesis

ABSTRACT Panmasala containing tobacco was introduced in the Indian market during the 1970s. Panmasala consists of areca nut (betel nut), catechu, lime, cardamom, spices, and unspecified flavoring agents, etc., with tobacco locally known as gutkha or without tobacco (Plain or sada), and consumed abundantly in India and also other parts of the world, predominantly in South East Asian countries. Available studies demonstrate that the habits of chewing panmasala gutkha or plain by students and adolesescents are on the increase, which may lead to deterioration of oral health and other organ systems. Based on the experimental as well as clinical studies available on panmasala as well as on different components of panmasala, this review suggests that it has the potential in causation of various oral diseases such as Oral Sub Mucosis Fibrosis (OSMF) and leucoplakia which may lead to oral cancer. Studies reviewed on these chewing mixtures also reveal that it is likely to be carcinogenic, as tobacco and areca nut have carcinogenic potential and both have encompassing addictive potential leading to dependence on chewing mixture containing areca nut and tobacco. These mixtures might not only lead to cancer but may also affect other organs of the body, including oral hard tissues in the form of dental attrition and sensitivity. There is a need to consider the potential health hazards associated with the habits of these products, especially oral cancer. More research is needed to find out early changes which could be reversible and also intervention measures through education to desist people in indulging in such habits.

Characterization of protein adducts formed by toxic alkaloids by nano-scale liquid chromatography with mass spectrometry

Betel quid chewing is associated with cytotoxicity, genotoxicity and carcinogenicity in diseases such as oral cancer, liver cirrhosis, hepatocellular carcinoma and diabetes mellitus. Arecoline and arecaidine, which are the main alkaloids in the areca nut, are potential exposure biomarkers in habitual betel quid users. This study developed a method of detecting arecoline- and arecaidine-protein adducts by mass spectrometry (MS). First, bovine serum albumin was used to predict and confirm the binding sites of proteins modified by arecoline or arecaidine. Cells were then treated with arecoline to identify new protein adducts after cellular metabolic processing. Finally, human plasma was used to model long-term exposure to arecoline and arecaidine. Following isolation proteins were tryspin digested. The peptides afforded were separated and analyzed by nano-scale liquid chromatography with MS using an LTQ Orbitrap mass spectrometer. The experimental findings showed that cysteine is the predominant amino acid in protein adduct formation. The goal of this study was to establish a screening platform for identifying novel protein adducts that form covalent bonds with arecoline or arecaidine. Use of this strategy to survey new protein-toxic adducts may help to identify novel biomarkers of betel nut exposure.

Genomic alterations in breast cancer patients in betel quid and non betel quid chewers

Betel Quid (BQ) chewing independently contributes to oral, hepatic and esophageal carcinomas. Strong association of breast cancer risk with BQ chewing in Northeast Indian population has been reported where this habit is prodigal. We investigated genomic alterations in breast cancer patients with and without BQ chewing exposure. Twenty six BQ chewers (BQC) and 17 non BQ chewer (NBQC) breast cancer patients from Northeast India were analyzed for genomic alterations and pathway networks using SNP array and IPA. BQC tumors showed significantly (P<0.01) higher total number of alterations, as compared with NBQC tumors, 48±17% versus 32±25 respectively. Incidence of gain in fragile sites in BQC tumors were significantly (P<0.001) higher as compared with NBQC tumors, 34 versus 23% respectively. Two chromosomal regions (7q33 and 21q22.13) were significantly (p<0.05) associated with BQC tumors while two regions (19p13.3–19p12 and 20q11.22) were significantly associated with NBQC tumors. GO terms oxidoreductase and aldo-keto reductase activity in BQC tumors in contrast to G-protein coupled receptor protein signaling pathway and cell surface receptor linked signal transduction in NBQC tumors were enriched in DAVID. One network “Drug Metabolism, Molecular Transport, Nucleic Acid Metabolism” including genes AKR1B1, AKR1B10, ETS2 etc in BQC and two networks “Molecular Transport, Nucleic Acid Metabolism, Small Molecule Biochemistry” and “Cellular Development, Embryonic Development, Organismal Development” including genes RPN2, EMR3, VAV1, NNAT and MUC16 etc were seen in NBQC. Common alterations (>30%) were seen in 27 regions. Three networks were significant in common regions with key roles of PTK2, RPN2, EMR3, VAV1, NNAT, MUC16, MYC and YWHAZ genes. These data show that breast cancer arising by environmental carcinogens exemplifies genetic alterations differing from those observed in the non exposed ones. A number of genetic changes are shared in both tumor groups considered as crucial in breast cancer progression.

Association of betel nut with carcinogenesis: revisit with a clinical perspective

Betel nut (BN), betel quid (BQ) and products derived from them are widely used as a socially endorsed masticatory product. The addictive nature of BN/BQ has resulted in its widespread usage making it the fourth most abused substance by humans. Progressively, several additives, including chewing tobacco, got added to simple BN preparations. This addictive practice has been shown to have strong etiological correlation with human susceptibility to cancer, particularly oral and oropharyngeal cancers.

The PUBMED database was searched to retrieve all relevant published studies in English on BN and BQ, and its association with oral and oropharyngeal cancers. Only complete studies directly dealing with BN/BQ induced carcinogenesis using statistically valid and acceptable sample size were analyzed. Additional relevant information available from other sources was also considered.

This systematic review attempts to put in perspective the consequences of this widespread habit of BN/BQ mastication, practiced by approximately 10% of the world population, on oral cancer with a clinical perspective. BN/BQ mastication seems to be significantly associated with susceptibility to oral and oropharyngeal cancers. Addition of tobacco to BN has been found to only marginally increase the cancer risk. Despite the widespread usage of BN/BQ and its strong association with human susceptibility to cancer, no serious strategy seems to exist to control this habit. The review, therefore, also looks at various preventive efforts being made by governments and highlights the multifaceted intervention strategies required to mitigate and/or control the habit of BN/BQ mastication.

Histopathological Assessment in Glossectomy

Objectives

The aim of the study was to gather information on outcomes and effect sizes of 2 surgical methods of glossectomy by using a grade system and an objective measure of artifacts in micrometers (µm). The collected data would be used to plan a definitive study.

Study Design

Pilot study.

Setting

Tertiary referral center.

Material and Methods

Nineteen patients affected with tongue cancer were consecutively enrolled in a pilot study and treated by partial glossectomy. Eleven patients (57.89%) of group A were treated with monopolar electrocautery, while 8 patients (42.10%) of group B were treated with Harmonic Focus Curved Shears. Specimens were examined by a pathologist blinded to the surgical procedure, using a 4-grade system for margin artifact assessment (margin fragmentation, cautery/crush artifact, extravascular blood clot, capillary congestion) and for measuring artifact depth.

Results

Artifact depth was more relevant in group A (765,633 µm) than in group B (473,939 µm). The difference between groups was significant at the 95% confidence interval ( P < .0001). Margin fragmentation and capillary congestion compared between the 2 groups were of no significance. There were less cautery/crush artifacts and extravascular blood clots observed in the harmonic shears group.

Conclusion

When used to perform a partial glossectomy, Harmonic Focus Curved Shears produce less cautery/crush artifact and a smaller artifact depth compared with monopolar cautery.

Nitric oxide and oral cancer: a review

Nitric oxide (NO), a short-lived, endogenously produced gas, plays key role in various physiological as well as pathological processes. NO-inducing cell signaling events within the cell producing it and the diffusibility of it in other cells have led to the discovery of various physiological functions of NO including vasodilation, respiration, cell migration, immune response and apoptosis. On the other hand, excessive and unregulated NO synthesis has been implicated in many pathophysiological conditions including cancer. Research on NO, during the past few years is one of the growing areas in cancer biology. The high incidence of oral cancer and precancer has been linked with habits of tobacco chewing and smoking and NO has been said as the "messenger of death" in tobacco related diseases. NO seems to play a part in various stages of carcinogenesis from initiation to progression. However, there is considerable controversy and confusion in understanding its role in cancer biology. It is said to have both, tumoricidal as well as tumor promoting effects and these depend on its timing, location and concentration. Further, NO has also been shown to have antitumor, chemopreventive and therapeutic abilities. Here is an overview in which efforts are made to understand the role of this molecule in oral carcinogenesis.

Epidemiology of human papillomavirus-related head and neck cancer

Human papillomavirus (HPV) is now recognized to cause a subset of head and neck squamous cell carcinomas (HNSCC). Although excessive tobacco and alcohol use continue to be important risk factors for HNSCC, epidemiologic studies suggest that more than 25% of HNSCC are now caused by HPV. The incidence of HPV-related HNSCC is increasing, highlighting the need to understand the oral HPV infections causing these cancers. This article reviews the evidence for a causal association between HPV and HNSCC, examines the changing epidemiologic trends of HNSCC, and discusses what is currently known about oral HPV infection, natural history, and transmission.

Salivary lipid peroxidation and total sialic acid levels in smokers and smokeless tobacco users as Maraş powder

Maraş powder (MP), a different type of smokeless tobacco (ST) and prepared from a tobacco of species Nicotiana rustica Linn, is widely used in Turkey. We aimed to investigate the effects of MP on salivary total sialic acid (TSA) and malondialdehyde (MDA) levels and to compare these parameters in smokers and MP users (MPUs). The salivary TSA and MDA concentrations were significantly higher in the smokers and MPU than those of control subjects and also in MPU than that of smokers. We have also observed that as the number of cigarettes consumed and MP amount increases, TSA and MDA levels increase too. In smokers, MDA values were significantly correlated with the number of cigarettes smoked and the duration of smoking. In MPU, both MDA and TSA levels were significantly correlated with the duration of MP use and the amount of daily consumed MP. We have concluded increased salivary TSA and MDA levels associated in MPU and smokers. Results can help to evaluate harmful effects of these habits. It is important to point out that bigger change in the measured parameters has been observed for MP use. This observation may be an important indication of harmful effects of ST use as MP.

Oral microbial carriage in oral squamous cell carcinoma patients at the time of diagnosis and during radiotherapy - a comparative study

OBJECTIVES

Tobacco chewing habit, presence of squamous cell carcinoma in oral cavity and radiotherapy causes alterations in healthy oral microflora. Abnormal flora developed due to radiotherapy in oral squamous cell carcinoma (OSCC) patients can exacerbate mucositis and can cause systemic infections. The role of oral microorganisms in carcinogenesis is gaining interest recently. Abnormal flora in development of second tumor in the field of first tumor is to be established. The study fundamentally tries to evaluate the shift that occurs during the radiotherapy in OSCC patients.

METHODS

Microbial analysis of saliva samples from OSCC patients undergoing radiotherapy, tobacco chewers and controls was undertaken. The microorganisms were grouped into categories as total aerobes, total anaerobes, candida, coliforms and gram negative anaerobic bacteria.

RESULTS

The frequency of isolation of total aerobes, total anaerobes, coliforms and gram negative anaerobic bacteria was significantly high in OSCC patients compared to healthy controls whereas candida was isolated most frequently during radiation period. The tobacco chewers showed significant increase in colony forming units of total aerobes and coliforms. All the microbial groups were high in OSCC and radiotherapy patients. While OSCC patients showed significant increase in total anaerobes and gram negative anaerobes, candida was increased in radiotherapy patients only.

CONCLUSION

Habits promote coliforms. Tumor supports efficiently anaerobes and candida. The latter is supported more by radiation. The study stresses the importance on administration of appropriate antimicrobial therapy right at the time of diagnosis of the lesion.

Arecanut as an emerging etiology of oral cancers in India

Arecanut (AN) usage is widespread in Asian countries, especially India and Taiwan. The incidence of oral cancer is increasing day by day, but there is no exponential increase with tobacco usage. Especially in the country like Taiwan where betel quid mostly do not contain tobacco, AN can be correlated with the increased incidence of cancer. There are different studies in the literature about AN and oral cancer but none of them have concluded with the definite pathway for carcinogenesis. The present paper includes reviews of the literature for AN and oral cancer and summarizes the possible mechanisms associated with AN-induced carcinogenesis; and we have also tried to propose pathway of carcinogenesis.

Effect of α-tocopherol on salivary reactive oxygen species and trace elements in oral submucous fibrosis

BACKGROUND

Oral submucous fibrosis (OSMF) is a chronic debilitating disease and a well-recognized, potentially malignant condition of the oral cavity associated with betel quid chewing. Betel quid chewing is a popular oral habit in India and shows strong association in the incidence of OSMF. The objective of the study was to determine the levels of trace elements, pro-oxidants and reactive oxygen species (ROS) in saliva of betel quid chewers and OSMF patients, which may help in the diagnosis of cancer progression in the oral cavity.

METHODS

A total of 35 cases of OSMF and 35 cases of healthy individuals were included in the present study. The salivary status of ROS, pro-oxidants and some trace elements was studied in OSMF patients and normal healthy individuals.

RESULTS

The levels of lipid peroxides (P < 0.001), conjugated dienes (P < 0.01), hydroxyl radicals (P < 0.01), superoxide dismutase (P < 0.05), copper (P < 0.05), calcium (P < 0.01), magnesium (NS), potassium (P < 0.05) and iron (P < 0.05) in OSMF patients were elevated when compared with normal healthy individuals. The levels of hydrogen peroxide (P < 0.05) and sodium (P < 0.01) in OSMF patients were found to be decreased when compared with control subjects. A significant alteration was noticed after supplementing with α-tocopherol in oral precancerous patients.

CONCLUSION

These parameters may help in the detection of the severity of oral diseases.

Predictive role of XRCC5/XRCC6 genotypes in digestive system cancers

Cancers are a worldwide concern; oral, esophageal and gastrointestinal cancers represent important causes of cancer-related mortality and contribute to a significant burden of human health. The DNA repair systems are the genome caretakers, playing a critical role in the initiation and progression of cancers. However, the association between the genomic variations of DNA repair genes and cancer susceptibility is not well understood. This review focuses on the polymorphic genotypes of the non-homologous end-joining DNA repair system, highlighting the role of two genes of this pathway, XRCC5 and XRCC6, in the susceptibility to digestive system cancers and discussing their potential contributions to personalized medicine.

Genome-wide expression and copy number analysis identifies driver genes in gingivobuccal cancers

The molecular mechanisms contributing to the development and progression of gingivobuccal complex (GBC) cancers-a sub-site of oral cancer, comprising the buccal mucosa, the gingivobuccal sulcus, the lower gingival region, and the retromolar trigone-remain poorly understood. Identifying the GBC cancer-related gene expression signature and the driver genes residing on the altered chromosomal regions is critical for understanding the molecular basis of its pathogenesis. Genome-wide expression profiling of 27 GBC cancers with known chromosomal alterations was performed to reveal differentially expressed genes. Putative driver genes were identified by integrating copy number and gene expression data. A total of 315 genes were found differentially expressed (P ≤ 0.05, logFC > 2.0) of which 11 genes were validated by real-time quantitative reverse transcriptase-PCR (qRT-PCR) in tumors (n = 57) and normal GBC tissues (n = 18). Overexpression of LY6K, in chromosome band 8q24.3, was validated by immunohistochemical (IHC) analysis. We found that 78.5% (2,417/3,079) of the genes located in regions of recurrent chromosomal alterations show copy number dependent expression indicating that copy number alteration has a direct effect on global gene expression. The integrative analysis revealed BIRC3 in 11q22.2 as a candidate driver gene associated with poor clinical outcome. Our study identified previously unreported differentially expressed genes in a homogeneous subtype of oral cancer and the candidate driver genes that may contribute to the development and progression of the disease. © 2011 Wiley Periodicals, Inc.

Modern surgical management of tongue carcinoma - a clinical retrospective research over a 12 years period

Objectives

In this retrospective study, we present a clinical review of our experience with tongue cancer in order to obtain valid criteria for therapeutic decision-making.

Materials and methods

Between August 1999 and June 2011, a total of 398 patients with squamous cell carcinoma of the tongue were treated at the Department of Oral and Maxillofacial Surgery, King Edward Medical University Lahore Pakistan. Data concerning patient characteristics, clinical and pathologic tumour characteristics and treatment strategies and their results were obtained from a retrospective review of medical records. The average follow-up was 4.6 years. Statistical analysis for survival was calculated by the method of Kaplan and Meier.

Results

There were 398 total patients. The mean age at diagnosis was 49.5 years,. 224 (56.3%) were male and 174 (43.7%) female (male/female ratio = 1.3:1).332/398 patients received surgical treatment, whereas 66 patients were excluded from surgical treatment and received primary radio (chemo) therapy after biopsy. Tongue carcinoma patients treated by non surgical treatment modalities had 5 years survival rate of 45.5% and patients with surgical intervention had survival rate of 96.1%.

Conclusions

We recommend categorical bilateral neck dissection in order to reliably remove occult lymph node metastases. Adjuvant treatment modalities should be applied more frequently in controlled clinical trials and should generally be implemented in cases with unclear margins and lymphatic spread.

Clinical relevance

This study provides modern treatment strategies for the tongue carcinoma.

Non-invasive measurement of the microvascular properties of non-dysplastic and dysplastic oral leukoplakias by use of optical spectroscopy

Differential Path-length Spectroscopy (DPS) was used to non-invasively determine the optical properties of oral leukoplakias in vivo. DPS yields information on microvascular parameters such as the mucosal blood content, the microvascular blood oxygenation and the average micro-vessel diameter as well as on tissue morphological parameters such as the scattering slope and scattering amplitude. DPS measurements were made on non-dysplastic and dysplastic oral leukoplakias using a novel fiber-optic probe, and were correlated to the histological outcome of biopsies taken from the same location. Our data show borderline significant increases in mucosal blood content in dysplastic lesions compared to non-dysplastic lesions, with no changes in microvascular oxygen saturation and light scattering signatures. These results suggest that dysplastic and non-dysplastic leukoplakias may be discriminated non-invasively in vivo through differences in their microvascular properties, if they can be reproducibly quantified in the presence of a variable thickness keratin layer that optically shields the mucosal layer.

Areca nut in pathogenesis of oral submucous fibrosis: revisited

BACKGROUND

Oral submucous fibrosis is a disease due to a chronic, insidious change in fibro-elasticity, characterized by burning sensation in the oral cavity, blanching, and stiffening of the oral mucosa and oropharynx leading to trismus and inability to open the mouth. The symptoms and signs depend on the progression of the lesions and number of affected sites. It is predominantly seen in Indians and other Asians. Once the disease has developed, there is neither regression nor any effective treatment. It is considered as a pre-malignant stage of oral cancer, and the reported risk of malignant transformation varies from 2.3-7.6%.

CONCLUSIONS

The common etiological factor considered for this unremitting disease is use of areca nut; however, the precise mechanism still remains elusive and controversial. A wide range of treatment consisting of drugs, surgical therapy, and physiotherapy have been attempted till date, with varying degrees of benefit, but none of them have proved to be a cure for this disease. This field remains open for clinical trials and research. This paper aims to give an overview on the role of areca nut in the pathogenesis and malignant potential of oral submucous fibrosis.

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.

Cigarette smoking induces overexpression of c-Met receptor in microvessels of oral lichen planus

INTRODUCTION

Cigarette smoking is related to many pathological conditions; however, chemical substances affect the oral cavity first, so it is important to consider its influence on oral mucosa and oral potentially pre-malignant lesions. The aim of this study was to investigate the effect of smoking on microvessel density in oral lichen planus. Special emphasis was placed on examining the relationship between the expression of c-Met receptor in blood vessels and smoking habits.

MATERIAL AND METHODS

This study included 34 patients with oral lichen planus diagnosed clinically and verified by histopathological examination and 12 healthy individuals as controls. Biopsy of oral mucosa was performed and specimens were examined for immunohistochemical CD34 and c-Met receptor expression. The microvessel density was established by evaluation of the five most vascular areas within a section.

RESULTS

Compared to normal oral mucosa, in lichen planus patients, significantly higher blood vessel density and c-Met expression were noted. Irregular distribution of microvessels was typical for oral lichen planus. Also, microvessel density was higher in cigarette smoking patients' tissues than in non-smoker specimens. Furthermore, the association of c-Met expression with smoking habit was statistically significant.

CONCLUSIONS

Cigarette smoking habit has a direct impact on the oral lichen planus course; therefore, close follow-up of these patients is mandatory.

Habits with killer instincts: in vivo analysis on the severity of oral mucosal alterations using autofluorescence spectroscopy

Oral habits like chewing and smoking are main causes of oral cancer, which has a higher mortality rate than many other cancer forms. Currently, the long term survival rate of oral cancer is less than 50%, as a majority of cases are detected very late. The clinician's main challenge is to differentiate among a multitude of red, white, or ulcerated lesions. Hence, new noninvasive, reliable, and fast techniques for the discrimination of oral cavity disorders are to be developed. This study includes autofluorescence spectroscopic screening of normal volunteers with and without lifestyle oral habits and patients with oral submucous fibrosis (OSF). The spectra from different sites of habitués, non-habitués, and OSF patients were analyzed using the intensity ratio, redox ratio, and linear discriminant analysis (LDA). The spectral disparities among these groups are well demonstrated in the emission regions of collagen and Flavin adenine dinucleotide. We observed that LDA gives better efficiency of classification than the intensity ratio technique. Even the differentiation of habitués and non-habitués could be well established with LDA. The study concludes that the clinical application of autofluorescence spectroscopy along with LDA, yields spontaneous screening among individuals, facilitating better patient management for clinicians and better quality of life for patients.

Chewing areca nut, betel quid, oral snuff, cigarette smoking and the risk of oesophageal squamous-cell carcinoma in South Asians: a multicentre case-control study

Oesophageal cancer remains an important public health problem worldwide. This multicentre matched case-control study examined the chewing areca nut alone, betel quid with tobacco, oral snuff (snuff dipping) and cigarette smoking as the risk factors for oesophageal squamous-cell carcinoma. We enrolled 91 cases of oesophageal squamous-cell carcinoma and 364 matched controls from three tertiary-care hospitals in Karachi, Pakistan. A structured questionnaire was used to collect the data through face-to-face interview of the participants. Multivariable conditional logistic regression model showed that after adjusting for the effect of ethnicity, ever chewed areca nut alone (adjusted matched odds ratio (mOR(adj))=3.7; 95% confidence interval (CI): 1.6-8.5), ever chewed betel quid with tobacco (mOR(adj)=12.8; 95% CI: 6.3-26.2), ever practiced snuff dipping (mOR(adj)=4.3; 95% CI: 1.6-11.7) and ever smoked cigarettes (mOR(adj)=2.9; 95% CI: 1.4-5.9) were significantly and independently associated with oesophageal squamous-cell carcinoma status. The adjusted summary population attributable risk (PAR) percent for all four substances together was 67.0. Furthermore, despite incomplete synergy, there was manifold increase in the risk of oesophageal squamous-cell carcinoma, if the respondents ever smoked cigarettes and ever chewed betel quid with tobacco (mOR(adj)=21.4; 95% CI: 6.3-72.4) or if they ever smoked cigarettes and ever practiced snuff dipping (mOR(adj)=14.4; 95% CI: 2.3-91.1). The adjusted PAR (%) was higher for the dual practice of smoking cigarettes and chewing betel quid with tobacco (64.3) than the dual practice of smoking cigarettes and snuff dipping (32.2). Public awareness to curtail the addiction to these substances may result in a substantial reduction in the incidence of oesophageal squamous-cell carcinoma and related mortality in this and similar settings.

Arecoline augments cellular proliferation in the prostate gland of male Wistar rats

Areca nut chewing is the fourth most popular habit in the world due to its effects as a mild stimulant, causing a feeling of euphoria and slightly heightened alertness. Areca nuts contain several alkaloids and tannins, of which arecoline is the most abundant and known to have several adverse effects in humans, specially an increased risk of oral cancer. On evaluating the effects of arecoline on the male endocrine physiology in Wistar rats, it was found that arecoline treatment led to an overall enlargement and increase in the wet weight of the prostate gland, and a two-fold increase in serum gonadotropin and testosterone levels. Since the prostate is a major target for testosterone, the consequences of arecoline consumption were studied specifically in the prostate gland. Arecoline treatment led to an increase in the number of rough endoplasmic reticulum and reduction of secretory vesicles, signifying a hyperactive state of the prostate. Increased expression of androgen receptors in response to arecoline allowed for enhanced effect of testosterone in the prostate of treated animals, which augmented cell proliferation, subsequently confirmed by an increase in the expression of Ki-67 protein. Cellular proliferation was also the outcome of concomitant over expression of the G(1)-to-S cell cycle regulatory proteins, cyclin D1 and CDK4, both at the transcriptional and translational levels. Taken together, the findings provide the first evidence that regular use of arecoline may lead to prostatic hyperplasia and hypertrophy, and eventually to disorders associated with prostate enlargement.

Clinicopathological and prognostic implications of genetic alterations in oral cancers

This study evaluated the clinicopathological and prognostic implications of genetic alterations characterizing oral squamous cell carcinoma(OSCC). Comparative genomic hybridization(CGH) was used to identify chromosomal alterations present in primary OSCCs obtained from 97 pateints. In this population, tobacco use was a significant risk factor for OSCC. By contrast, all 97 of our samples are negative for human papillomavirus (HPV) DNA integration, which is another known risk factor for OSCC in certain populations. Results of the Fisher's exact test followed by Benjamini-Hochberg correction for multiple testing, showed a correlation of 7p gain and 8p loss with node-positive OSCC (p≤0.04 for both genetic alterations) and association of 11q13 gain with high-grade OSCC (p≤0.05). Univariate Cox-proportional hazard models, also corrected for multiple testing, showed significant association of 11q13 gain and 18q loss with decreased survival (p≤0.05). These findings were supported by multivariate analysis which revealed that 11q13 gain and 18q loss together serve as a strong bivariate predictor of poor prognosis. In conclusion, our study has identified genetic alterations that correlate significantly with nodal status, grade, and poor survival status of OSCC. These potential biomarkers may aid the current TNM system for better prediction of clinical outcome.

Areca nut extracts enhance the development of CD11b(+) Gr-1(+) cells with the characteristics of myeloid-derived suppressor cells in antigen-stimulated mice

BACKGROUND

Areca quid chewing is an etiological factor contributing to the development of oral cancer and pre-cancers, whose pathophysiology has been linked to inflammation and immune deterioration. Myeloid-derived suppressor cells (MDSC) play a key role in the regulation of immunity under certain pathological conditions, such as inflammation and cancer. As areca nut extracts (ANE) have been reported to induce a proinflammatory effect in antigen-stimulated mice, we hypothesized that ANE might enhance the development of MDSC.

METHODS

Ovalbumin (OVA)-sensitized BALB/c mice were daily administered with ANE (5-50 mg/kg), polyphenol-enriched ANE (PANE; 25 mg/kg) or arecoline (5 mg/kg) by intraperitoneal injection for 10 doses. The mouse footpads were then subcutaneously challenged with OVA to induce local inflammatory responses.

RESULTS

ANE and PANE treatment significantly increased the spleen index and the population of CD11b(+) Gr-1(+) cells in the spleen and peripheral blood, whereas arecoline was inactive. In addition, ANE and PANE treatment enhanced the expression of cytokines and enzymes associated with the immunosuppressive function of MDSC, including IL-10, arginase-I and iNOS in splenic CD11b(+) cells. Concordantly, ANE and PANE treatment augmented the infiltration of Gr-1(+) IL-10(+) cells in the footpads challenged with OVA.

CONCLUSIONS

Our results suggested that areca nut constituents, in particular, polyphenols enhanced the development of myeloid-derived suppressor cells in vivo, which may be a critical mechanism linking inflammation and the compromised immunity reported to be associated with the pathophysiology of areca-related oral diseases.

Role of the XRCC5/XRCC6 dimer in carcinogenesis and pharmacogenomics

Over the past few decades, the incidence of cancer has rapidly increased all over the world and cancer remains a major threat to public health. It is believed that cancer results from a series of genetic alterations that lead to the progressive disorder of the normal mechanisms controlling cell proliferation, differentiation, death and/or genomic stability. The response of the cell to genetic injury and its ability to maintain genomic stability by means of a variety of DNA repair mechanisms are therefore essential in preventing tumor initiation and progression. From the same viewpoint, the relative role of DNA repair as a biomarker for prognosis, predictor of drug and therapy responses or indeed as a target for novel gene therapy, is very promising. In this article, we have summarized the studies investigating the association between the XRCC5/XRCC6 dimer and the susceptibility to multiple cancers and discuss its role in carcinogenesis and its potential application to anticancer drug discovery.

High ERCC1 expression predicts cisplatin-based chemotherapy resistance and poor outcome in unresectable squamous cell carcinoma of head and neck in a betel-chewing area

BACKGROUND

This study was to evaluate the effect of excision repair cross-complementation group 1(ERCC1) expression on response to cisplatin-based induction chemotherapy (IC) followed by concurrent chemoradiation (CCRT) in locally advanced unresectable head and neck squamous cell carcinoma (HNSCC) patients.

METHODS

Fifty-seven patients with locally advanced unresectable HNSCC who received cisplatin-based IC followed by CCRT from January 1, 2006 through January 1, 2008. Eligibility criteria included presence of biopsy-proven HNSCC without a prior history of chemotherapy or radiotherapy. Immunohistochemistry was used to assess ERCC1 expression in pretreatment biopsy specimens from paraffin blocks. Clinical parameters, including smoking, alcohol consumption and betel nuts chewing, were obtained from the medical records.

RESULTS

The 12-month progression-free survival (PFS) and 2-year overall survival (OS) rates of fifty-seven patients were 61.1% and 61.0%, respectively. Among these patients, thirty-one patients had low ERCC1 expression and forty-one patients responded to IC followed by CCRT. Univariate analyses showed that patients with low expression of ERCC1 had a significantly higher 12-month PFS rates (73.3% vs. 42.3%, p < 0.001) and 2-year OS (74.2 vs. 44.4%, p = 0.023) rates. Multivariate analysis showed that for patients who did not chew betel nuts and had low expression of ERCC1 were independent predictors for prolonged survival.

CONCLUSIONS

Our study suggest that a high expression of ERCC1 predict a poor response and survival to cisplatin-based IC followed by CCRT in patients with locally advanced unresectable HNSCC in betel nut chewing area.

Current management of advanced resectable oral cavity squamous cell carcinoma

The oral cavity is the most common site of head and neck squamous cell carcinoma, a disease which results in significant morbidity and mortality worldwide. Though the primary modality of treatment for patients with oral cavity cancer remains surgical resection, many patients present with advanced disease and are thus treated using a multi-disciplinary approach. Patients with extracapsular spread of lymphatic metastasis and surgical margins that remain positive have been found to be at high risk for local-regional recurrence and death from disease, and are most often recommended to receive both post-operative radiation as well as systemic chemotherapy. The basis for this approach, as well as scientific developments that underly future trials of novels treatments for patients with high-risk oral cavity cancer are reviewed.

Fenofibrate exhibits a high potential to suppress the formation of squamous cell carcinoma in an oral-specific 4-nitroquinoline 1-oxide/arecoline mouse model

The excessive use of areca nut and/or tobacco may induce the production of free radicals and reactive oxygen species, which affect the lipid contents of the cell membrane and are possibly involved in tumorigenic processes in the oral cavity. The aim of this study was to investigate the therapeutic efficacy of fenofibrate (0.1% or 0.3%, w/w), a ligand of the peroxisome proliferator-activated receptor alpha (PPARα), in a 4-nitroquinoline 1-oxide (4-NQO)/arecoline-induced oral cancer mouse model. The carcinogen, 4-NQO/arecoline, was administrated to C57BL/6JNarl mice for 8weeks followed by fenofibrate treatment for 12 or 20weeks. After 28weeks, changes in serum lipids, the multiplicity of tumor lesions, and tumor sizes were determined together with changes in the immunohistochemical expressions of PPARα, acetyl-coenzyme A carboxylase (ACC), the epidermal growth factor receptor (EGFR), and cyclooxygenase-2 (COX2). The results showed that when compared to the 4-NQO/arecoline only group, 0.3% fenofibrate treatment increased serum total cholesterol, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels. 0.3% fenofibrate treatment suppressed the incidence rate of tongue lesions, reduced the multiplicity of squamous cell carcinoma (SCC), decreased the tumor size, and increased the immunoreactivity of EGFR and COX2 in oral dysplasia but decreased EGFR and COX2 expressions in SCC. These findings indicated that fenofibrate reduced the tumor incidence rate and suppressed the tumor progression into SCC and that these molecular events might be linked to the EGFR and COX2 regulatory pathways. We suggest that fenofibrate provides a new strategy for preventing oral tumor progression.

Betel nut chewing and subclinical ischemic heart disease in diabetic patients

Background. This study investigated the association between betel nut chewing and subclinical ischemic heart disease (IHD) in Taiwanese type 2 diabetic patients. Methods. A total of 394 male patients aging ≥45 years and without previous heart disease were studied. Among them 349 had no habit of chewing betel nut and 45 possessed the habit for ≥5 years. Subclinical IHD was diagnosed by a Minnesota-coded resting electrocardiogram and was present in 71 cases. Statistical analyses were performed considering confounding effects of age, diabetic duration, smoking, body mass index, blood pressure, dyslipidemia, and metabolic control status. Results. Betel nut chewers were younger and had higher prevalence of smoking (86.7% versus 60.5%), higher body mass index, poorer glycemic control, and higher prevalence of subclinical IHD (28.9% versus 16.6%). Patients with subclinical IHD were older and had higher prevalence of betel nut chewing (18.0% versus 9.9%). The multivariate-adjusted odds ratio for subclinical IHD for chewers versus nonchewers was 4.640 (1.958–10.999). The adjusted odds ratios in younger or older patients divided by the median age of 63 years were similar: 4.724 (1.346–16.581) and 4.666 (1.278–17.028), respectively. Conclusions. Betel nut chewing is significantly associated with increased risk of subclinical IHD.

High-throughput simultaneous analysis of five urinary metabolites of areca nut and tobacco alkaloids by isotope-dilution liquid chromatography-tandem mass spectrometry with on-line solid-phase extraction

BACKGROUND

Areca nut and tobacco are commonly used drugs worldwide and have been frequently used in combination. We describe the use of on-line solid-phase extraction and isotope-dilution liquid chromatography-tandem mass spectrometry for the simultaneous measurement of five major urinary metabolites of both areca nut and tobacco alkaloids, namely, arecoline, arecaidine, N-methylnipecotic acid, nicotine, and cotinine.

METHODS

Automated purification of urine was accomplished with a column-switching device. After the addition of deuterium-labeled internal standards, urine samples were directly analyzed within 13 minutes. This method was applied to measure urinary metabolites in 90 healthy subjects to assess areca nut/tobacco exposure. Urinary time course of arecoline, arecaidine, and N-methylnipecotic acid was investigated in five healthy nonchewers after oral administration of areca nut water extracts.

RESULTS

The limits of detection were 0.016 to 0.553 ng/mL. Interday and intraday imprecision were <10%. Mean recoveries of five metabolites in urine were 97% to 114%. Mean urinary concentrations of arecoline, arecaidine, N-methylnipecotic acid, nicotine, and cotinine in regular areca nut chewers also smokers were 23.9, 5,816, 1,298, 2,635, and 1,406 ng/mg creatinine, respectively. Time course study revealed that after administration of areca nuts extracts, the major urinary metabolite was arecaidine with a half-life of 4.3 hours, followed by N-methylnipecotic acid with a half-life of 7.9 hours, and very low levels of arecoline with a half-life of 0.97 hour.

CONCLUSIONS

This on-line solid-phase extraction liquid chromatography-tandem mass spectrometry method firstly provides high-throughput direct analysis of five urinary metabolites of areca nut/tobacco alkaloids.

IMPACT

This method may facilitate the research into the oncogenic effects of areca nut/tobacco exposure.

Extracapsular spread in oral squamous cell carcinoma

BACKGROUND

Extracapsular spread (ECS) in the cervical lymph nodes represents the most significant adverse prognostic indicator in oral squamous cell carcinoma (OSCC).

METHODS

In a consecutive cohort of OSCC treated by primary surgery, ECS was seen in 25% (101) of 400 patients.

RESULTS

ECS doubled the incidence of local recurrence and distant metastases, but tripled regional failure. The recurrences occurred sooner in ECS than in non-ECS cases (206 vs 334 days, p = .04). Patients with macroscopic ECS had a 5-year overall survival (OS) of 19% compared with 31% in microscopic ECS. MRI neck staging offered poor sensitivity, especially in microscopic ECS. Age >75 years, smoking, and heavy use of alcohol were independent predictors of ECS, which may implicate a failure of immunosurveillance by the host as much as adverse biology of the tumor.

CONCLUSIONS

Reporting of ECS is essential in accurate prognostication, and we advocate that all patients with OSCC and ECS should be grouped as pN3 on the basis of their prognosis. (c) 2009 Wiley Periodicals, Inc. Head Neck, 2010.

Oral cancer in Myanmar: a preliminary survey based on hospital-based cancer registries

The occurrence of oral cancer is not clearly known in Myanmar, where betel quid chewing habits are widely spread. Since betel quid chewing has been considered to be one of the important causative factors for oral cancer, the circumstantial situation for oral cancer should be investigated in this country. We surveyed oral cancer cases as well as whole body cancers from two cancer registries from Yangon and Mandalay cities, both of which have representative referral hospitals in Myanmar, and we showed that oral cancer stood at the 6th position in males and 10th in females, contributing to 3.5% of whole body cancers. There was a male predominance with a ratio of 2.1:1. Their most frequent site was the tongue, followed by the palate, which was different from that in other countries with betel quid chewing habits. About 90% of male and 44% of female patients had habitual backgrounds of chewing and smoking for more than 15 years. The results revealed for the first time reliable oral cancer frequencies in Myanmar, suggesting that longstanding chewing and smoking habits are etiological backgrounds for oral cancer patients.

Oral cavity cancer in developed and in developing countries: population-based incidence

BACKGROUND

The incidence of oral cavity cancer (OCC) is not well documented because it is rarely described in accord with the anatomic definition but is usually grouped with oropharyngeal subsites. We studied the incidence of OCC in developed and in developing countries.

METHODS

The age-standardized and age-specific incidence rates of OCC were calculated for the period 1998-2002, using the topographic definition used by the Union Internationale Contre le Cancer (UICC), based on data from CI5-IX.

RESULTS

The highest rates are observed in Pakistan, Brazil, India, and France and were consistent with country-specific risk factors and their prevalence.

CONCLUSIONS

In developing countries, people are exposed to a wider range of risk factors, starting at younger ages, and primary prevention measures and policies are needed. Awareness of professionals must be improved to identify people at risk and target them for prevention and to minimize the consequences of OCC.