Role of areca nut consumption in the cause of oral cancers. A cytogenetic assessment

Areca nut and smokeless tobacco exposure induces micronucleus, other nuclear abnormalities and cytotoxicity in early chick embryo

Areca nut (AN) and smokeless tobacco (SLT) are indiscriminately consumed among the populations of Southeast and South Asian countries, even by women during the gestational period. This study aimed to investigate the genotoxic and cytotoxic potentials of AN and Sadagura (SG), a unique homemade SLT preparation, alone and in combination in early chick embryos. Fertile white leghorn chicken eggs were randomly divided into five treatment groups: vehicle control, positive control (Mitomycin C, 20 μg/egg), AN, SG, and AN+SG. AN, SG, and AN+SG were given at dosages of 0.125, 0.25, and 0.5 mg/egg. The hen's egg test for micronucleus induction (HET-MN) was performed in chick embryos to evaluate the genotoxic potential of the test agents. Furthermore, the cytotoxic potential was assessed by studying erythroblast cell populations and the polychromatic erythrocytes (PCEs) to normochromatic erythrocytes (NCEs) ratio. Our results indicated a significant increase (p < .001) in MN frequency and other nuclear abnormalities, suggesting the potential of AN and SG to cause genotoxicity. Also, AN and SG exposure alone and in combination considerably altered the erythroblast cell population (%) and the PCE to NCE ratio in all the treatment periods. Our findings established the genotoxic and cytotoxic potential of both AN and SG alone and in combination during early embryonic development in the chick embryo.

A Contemporary Exploration of Traditional Indian Snake Envenomation Therapies

Snakebite being a quick progressing serious situation needs immediate and aggressive therapy. Snake venom antiserum is the only approved and effective treatment available, but for selected snake species only. The requirement of trained staff for administration and serum reactions make the therapy complicated. In tropical countries where snakebite incidence is high and healthcare facilities are limited, mortality and morbidities associated with snake envenomation are proportionately high. Traditional compilations of medical practitioners’ personal journals have wealth of plant-based snake venom antidotes. Relatively, very few plants or their extractives have been scientifically investigated for neutralization of snake venom or its components. None of these investigations presents enough evidence to initiate clinical testing of the agents. This review focuses on curating Indian traditional snake envenomation therapies, identifying plants involved and finding relevant evidence across modern literature to neutralize snake venom components. Traditional formulations, their method of preparation and dosing have been discussed along with the investigational approach in modern research and their possible outcomes. A safe and easily administrable small molecule of plant origin that would protect or limit the spread of venom and provide valuable time for the victim to reach the healthcare centre would be a great lifesaver.

Chemical Composition, Pharmacological, and Toxicological Effects of Betel Nut

Betel nut, the fruit of Areca catechu L, has a long medical history in Southeast Asia. It is native to Malaysia and is cultivated and processed extensively in subtropical regions, such as South China and India. Betel nut almost appears as a "snack" in various occasions in most parts of China. Clinically, betel nut can play a certain pharmacology role and was used in malaria, ascariasis, arthritis, enterozoic abdominalgia, stagnation of food, diarrhea, edema, and beriberi. The nervous excitement of betel nut chewing has made it gradually become popular. However, chewing betel nut can induce oral submucosal fibrosis (OSF) and oral cancer (OC). At the same time, long-term chewing of betel nut also causes inhaled asthma, sperm reducing, betel quid dependence (BQD), and uterine and esophageal cancers. The main components of processed betel nut are the goal of this review. This study will mainly start from the pharmacological activity and toxicology study of betel nut in recent years, aiming to seek its advantages and disadvantages. In the meantime, this study will analyze and emphasize that betel nut and arecoline are the high-risk factors for oral cancer, which should arouse attention and vigilance of the public.

Comparing the Incidence of Buccal Mucosa Cancer in South Asian, White, and Black Populations Residing in the United States: A Cross-Sectional Analysis

Background:

Recreational use of the betel nut, which is common among the South Asian population, is a known risk factor for developing Head and Neck cancer. As South Asians comprise a significant proportion of the United States population, we seek to determine if those living within the country experience a higher rate of head and neck cancers compared to other races.

Methods:

Data of patients diagnosed with head & neck cancers from 2010-2016 was collected from the National Cancer Database^® and compared to race-matched US census data for each corresponding year to calculate incidence. Pairwise comparisons were performed between the incidence for South Asians versus Whites and South Asians versus Blacks using one sided Chi-square tests.

Results:

South Asians experienced a significantly higher incidence of buccal mucosa/vestibule cancers when compared to Whites or Blacks for every year between 2010-2016, but a comparatively lower incidence of larynx or oropharynx cancers.

Conclusions:

South Asians residing within the United States have a higher incidence of buccal mucosa/vestibule cancers, but a lower incidence of more common cancers, such as larynx or oropharynx cancer. This may suggest that the etiology behind the high buccal mucosa/vestibule cancer incidence is due to a social habit, as opposed to an inherent racial susceptibility.

Betel Quid Health Risks of Insulin Resistance Diseases in Poor Young South Asian Native and Immigrant Populations

Betel quid, traditionally prepared with areca nut, betel leaf, and slaked lime, has been consumed for thousands of years, mainly in the form of chewing. Originally used for cultural, medicinal, and ceremonial purposes mainly in South Asian countries, its use has recently spread across the globe due to its psychoactive, euphoric, and aphrodisiac properties. Now it is widely used as a social lubricant and source of financial profit. Unfortunately, the profit motive has led to high rates of habitual consumption with eventual conversion to addiction among young girls and boys. Moreover, the worrisome practice of including tobacco in quid preparations has grown, particularly among pregnant women. Major health concerns include increased rates of malignancy, oral pathology, and cardiovascular, hepatic, fertility, metabolic, and neuropsychiatric disorders. Metabolic disorders and insulin resistance disease states such as type 2 diabetes, obesity, and metabolic syndrome contribute to cognitive decline and neurodegeneration. Mechanistically, the constituents of areca nut/betel quid are metabolized to N-nitroso compounds, i.e., nitrosamines, which are carcinogenic at high doses and cause insulin resistance following chronic low-level exposures. From an epidemiological perspective, the rising tide of insulin resistance diseases including obesity, diabetes, and dementias that now disproportionately burden poor countries has been propagated by rapid commercialization and enhanced access to betel quid. Public health measures are needed to impose socially and ethically responsible barriers to yet another cause of global health disparity.

Do betel quid and areca nut chewing deteriorate prognosis of oral cancer? A systematic review, meta-analysis, and research agenda

OBJECTIVE

To explore the correlations between the habit of betel quid and areca nut (BQ-AN) chewing and the prognosis of oral cancer (OC).

METHODS

We performed a systematic review and meta-analysis to clarify this issue. Data searches were performed using PubMed, Web of Science, Epistemonikos, and Embase databases through November 2019. The primary outcome was the difference in the prognosis of OC between BQ-AN chewers and non-chewers, measured in terms of 5-year overall survival (OS) and 5-year disease-specific survival (DSS) log (HR) reported in articles. The pooled HR with 95% CI of 5-year OS and 5-year DSS was calculated using a fixed-effects model.

RESULTS

Ten articles with eleven OS or DSS survival studies (one of the articles contained two studies), which were published between 2003 and 2017, were eligible for inclusion in the present study. All the 11 studies were observational studies, among which 10 were retrospective and 1 was prospective. One study measured both OS and DSS. Eight studies, with a total of 2,761 patients, used 5-year OS as the primary endpoint and four studies, with a total of 2,551 patients, used 5-year DSS. Overall, the pooled HR evaluating BQ-AN chewers was 1.26 (95% CI: 1.09-1.46) for 5-year OS and 1.40 (95% CI: 1.15-1.70) for 5-year DSS, compared with non-chewers. There was a significant association between BQ-AN chewing and OC survival.

CONCLUSIONS

Betel quid and areca nut chewing is significantly associated with poor prognosis in patients with OC.

Study of salivary arecoline in areca nut chewers

Aims:

Arecoline, a predominant alkaloid present in arecanut, has been implicated in the pathogenesis of several oral diseases because of its mutagenic and carcinogenic potential. The response of cultured cells to arecoline is highly dependent on its concentration; arecoline stimulates cultured cells above 0.1 μg/ml and is cytotoxic above 10 μg/ ml. Although this alkaloid seems important for areca nut induced oral diseases and carcinogenesis, little is known of the levels achieved before, during and after chewing. Also, it is prudent to understand its effects in arecanut chewers for a comprehensive understanding of its pathogenesis. Accordingly, the present study quantified the salivary arecoline levels in arecanut chewers.

Materials and Methods:

The study participants were divided into Study Group A & B and Control Group C; unstimulated whole saliva was collected by spitting method for a period of 5 min. Then, participants in Group A and C chewed 0.5 g of areca nut without any other additives while in Group B were asked to chew 0.5 g of inert rubber base impression material. Stimulated whole saliva from all three groups was collected into graduated tubes during chewing at time intervals of 1, 3, 5, 10, 15, 20 and 25 min. Then, all participants were asked to remove nut particles or inert rubber base material from the mouth, and saliva samples were collected further up to 20 min, changing tubes at 5 min interval. Salivary arecoline was quantitated by HPLC-MS. The tabulation and descriptive statistics of the study were carried out.

Results:

In the present study, baseline levels of arecoline were zero in all three groups, whereas mean salivary arecoline levels during chewing were 76.93 ng/ml, 129.83 ng/ml and 64.83 ng/ml and after chewing were 196.17 ng/ml, 321.12 ng/ml and 43.75 ng/ml in Groups A, B and Control respectively, which were significantly higher than reported threshold levels.

Conclusions:

The data from this study reveals that a significant amount of arecoline would be trapped in oral cavity, or being re-circulated between blood and saliva might have resulted in surprisingly high levels of arecoline even 10 mins after chewing in both groups after which the levels started declining. The higher levels of salivary arecoline achieved during and after chewing are enough to cause cytotoxic and genotoxic effects on oral tissues over a period of time in chronic chewers. The great differences in salivary arecoline levels achieved during chewing, may contribute to the variable response to areca nut seen in communities where this habit is widespread. Areca nut users have persistent background salivary arecoline levels long after chewing, whereas concentrations achieved are highly variable and consistent with a role in oral pre-malignancy and malignancy..

Prognostic Stratification of Patients With Advanced Oral Cavity Squamous Cell Carcinoma

PURPOSE OF REVIEW

Prognosis of advanced oral squamous cell carcinoma remains a challenge for clinicians despite progress in its diagnosis and treatment over the past decades. In this review, we assessed clinicopathological factors and potential biomarkers along with their prognostic relevance in an attempt to develop optimal treatment strategies for these patients.

RECENT FINDINGS

In addition to several pathologic factors that have been proposed to improve prognostic stratification and treatment planning in the eighth edition of the American Joint Committee staging manual on cancer, we reviewed some other imaging and clinicopathological parameters demonstrated to be closely associated with patient prognosis, along with the biomarkers related to novel target or immune therapy. Evaluation of current literature regarding the prognostic stratification used in contemporary clinicopathological studies and progress in the development of targeted or immune therapy may help these patients benefit from tailored and personalized treatment and obtain better oncological results.

Assessment of micronuclei frequency in individuals with a habit of tobacco by means of exfoliated oral buccal cells

AIMS AND OBJECTIVES

To study the genotoxic effects of tobacco on the exfoliated buccal epithelial cells in patients with oral precancerous lesions (OPLs) and Patients with tobacco habit but without oral precancerous lesion(habit controls) by using micronucleus assay as well as the quantification and detection of the biomarkers in these premalignant lesions which will be helpful in finding those patients who are at higher risk for malignant transformation.

MATERIALS AND METHODS

Forty samples were collected from the right and left side of buccal epithelial cells obtained from 20 individuals, i.e., 10 patients with habit control and 10 patients with OPLs. Statistical analysis was performed by the Statistical Package for the Social Sciences version 21.0 Unpaired t-test was performed to determine the micronucleated cell (MNC) and micronuclei (MN) frequencies in individuals; significance was set at P > 0.05.

RESULTS

There was an increase in both the MNC and MN frequency from habit controls to OPLs, indicating that the number of cells with chromosomal damage and extent of chromosomal damage in each cell was high in OPLs.

CONCLUSION

The MN count can be used as a noninvasive tool for early detection, educating patients, screening a large population, and to check the risk for malignancy, which in turn may help in treatment planning.

DNA damage in peripheral blood leukocytes in tobacco users

AIM

To Quantify the DNA single-stranded breaks in the peripheral blood leukocytes (PBLs) of tobacco-habituated individuals with clinically normal mucosa and patients with oral carcinoma.

OBJECTIVES

To evaluate DNA damage levels in PBLs of tobacco-habituated individuals with clinically normal mucosa and patients with oral carcinoma and compare with a control group of healthy volunteers. To evaluate the extent of DNA damage in PBLs using Single Cell Gel Electrophoresis (SCGE) in the above groups.

MATERIALS AND METHODS

Patients who were attending the outpatient department were enrolled in this study. A control group of 30 healthy volunteers included in Group I were selected from various age groups who are not tobacco users in any form. Thirty patients with tobacco habituation but with clinically normal mucosa were included in Group II, while 30 tobacco-habituated patients with oral squamous carcinoma were included in Group III. A biopsy was taken from the representative area and confirmed histologically. Intravenous blood samples were collected from all the groups for evaluation of the extent of DNA damage using ethidium bromide-stained slides under fluorescent microscope. The DNA tail length was calculated by subtracting the diameter from the total length. Twenty-five randomly selected cells per slide were analyzed and mean calculated.

RESULTS

The mean DNA damage levels in patients with tobacco habits were compared with that of the control group and the results were found to be statistically significant. The mean DNA damage level in PBLs between tobacco-habituated patients with normal mucosa and oral cancer patients was found to be statistically significant. The DNA damage in cancer patients was compared with the control group and the results were found to be statistically significant.

CONCLUSION

DNA damage evaluation in PBLs by SCGE technique is a sensitive and reliable indicator of tobacco insult.

Clinical evidence of field cancerization in patients with oral cavity cancer in a betel quid chewing area

OBJECTIVES

We sought to investigate whether there is evidence of field cancerization in patients with oral cavity squamous cell carcinoma (OSCC) enrolled in a betel quid chewing area. We also assessed whether betel quid chewing is an independent risk factor for field cancerization in OSCC patients.

METHODS

We retrospectively examined the records of 1570 OSCC patients who underwent radical tumor resection between 1996 and 2011. A total of 1243 study participants (79%) had a positive history of betel quid chewing before surgery. Of the 767 patients treated with surgery alone, 599 (78%) were preoperative chewers, whereas a history of preoperative betel quid chewing was identified in 644 (80%) of the 803 patients who received adjuvant therapy. The 5-year control, survival, and second primary tumors (SPTs) rates served as the main outcome measures.

RESULTS

Regardless of the treatment modality, more than 70% of the SPTs were located in the oral cavity or soft palate. Despite a similar risk profile in terms of tumor depth, lymph node metastasis, and pathological margin status, preoperative chewers showed a significantly higher incidence of 5-year SPTs and local recurrences compared with non-chewers. Moreover, multivariate analysis demonstrated that preoperative betel quid chewing was an independent prognostic factor for 5-year local control and SPTs occurrence rates.

CONCLUSIONS

Our results demonstrate that preoperative betel quid chewers had a higher incidence of local recurrence and SPTs than non-chewers, suggesting that field cancerization may occur in OSCC patients with a history of betel quid chewing.

Cyclin d1 gene expression in oral mucosa of tobacco chewers"-an immunohistochemical study

OBJECTIVE

The objective of the present study was to evaluate the expression of cyclin D1 in normal oral mucosa of both non tobacco habituated and tobacco habituated individuals histologically and also compare and correlate cyclin D1 expression with histopathologically confirmed cases of oral squamous cell carcinomas.

STUDY DESIGN

The present study involved 20 cases of tobacco habituated individuals with normal oral mucosal tissue and 20 histopathologically confirmed cases of squamous cells carcinomas. Twelve cases of non tobacco habituated individuals served as control group. Chi-square analysis was used to determine statistical significance.

RESULTS

Fifty percent of control cases, 70% of squamous cell carcinoma cases and 80% of tobacco habituated individuals of clinically normal mucosa showed cyclin D1 positivity. Thirteen cases with tobacco chewing habit, with clinically normal mucosa, showed dysplasia, out of which seven were mildly dysplastic and six were moderately dysplastic. A larger percentage of cyclin D1 expression was observed in lower grade dysplasias (53.8%) than higher grade dysplasias (46.1%). However statistical analysis showed no significant association between groups. Chi-square value was < 7.82 for p=0.05.

CONCLUSION

The finding of cyclin D1 expression in 80% of tobacco users with clinically normal mucosa indicates that the mutation of cyclin D1 occurs early, even before clinical changes are apparent. This finding appears to be previously unreported. The presence of dysplasia in the same group and cyclin D1 expression in 84.6% of dysplastic cases show that the patients are susceptible for further changes, including progression to higher grades of dysplasia and development of carcinoma. Relatively lower expression of cyclin D1 positivity (70%), in oral cancer patients, when compared with tobacco users with clinically normal mucosa (80%) is indicative of increased traverse of the cell through the cell cycle, which may occur early in tumor progression. Cyclin D1 immunoreactivity was detected in all the three study groups.

Distinct involvement of 9p21-24 and 13q14.1-14.3 chromosomal regions in raw betel-nut induced esophageal cancers in the state of Meghalaya, India

BACKGROUND

Raw betel nut (RBN) chewing is an important contributing factor for esophageal squamous cell carcinoma (ESCC), although associated genomic changes remain unclear. One difficulty in assessing the effects of exclusively RBN induced genetic alterations has been that earlier studies were performed with samples of patients commonly using tobacco and alcohol, in addition to betel-quid. Both CDKN2A (at 9p21) and Rb1 gene (at 13q14.2) are regarded as tumor suppressors involved in the development of ESCC. Therefore, the present study aimed to verify the RBN's ability to induce ESCC and assess the involvement of CDKN2A and Rb1 genes.

METHODS

A panel of dinucelotide polymorphic markers were chosen for loss of heterozygosity studies in 93 samples of which 34 were collected from patients with only RBN-chewing habit. Promoter hypermethylation was also investigated.

RESULTS

Loss in microsatellite markers D9S1748 and D9S1749, located close to exon 1β of CDKN2A/ARF gene at 9p21, was noted in 40% ESCC samples with the habit of RBN-chewing alone. Involvement of a novel site in the 9p23 region was also observed. Promoter hypermethylation of CDKN2A gene in the samples with the habit of only RBN-chewing alone was significantly higher (p=0.01) than Rb1 gene, also from the samples having the habit of use both RBN and tobacco (p=0.047).

CONCLUSIONS

The data indicate that the disruption of 9p21 where CDKN2A gene resides, is the most frequent critical genetic event in RBN-associated carcinogenesis. The involvement of 9p23 as well as 13q14.2 could be required in later stages in RBN-mediated carcinogenesis.

Evaluation of PTEN immunoexpression in oral submucous fibrosis: role in pathogenesis and malignant transformation

Oral submucous fibrosis (OSMF) is a chronic debilitating disease and a premalignant condition of the oral cavity characterized by generalized submucosal fibrosis. Despite its precancerous nature, the molecular biology regarding its malignant potential has not been extensively studied. PTEN, a known tumor suppressor gene is mutated in a majority of human cancers and has also been implicated in several fibrotic disorders. The present study aims to evaluate the expression of PTEN in OSMF and oral squamous cell carcinoma (OSCC) and correlate it with the pathogenesis and malignant transformation of OSMF. 60 cases total of OSMF (30) and OSCC (30) were subjected to immunohistochemistry using PTEN antibody. Ten normal oral mucosa (NOM) specimens were also stained as controls. There was progressive loss of PTEN expression from normal mucosa to OSMF and OSCC (p ≤ 0.001). Significant differences were observed for PTEN expression between NOM and OSMF, OSMF and OSCC as well as NOM and OSCC. Though a progressive loss of PTEN was noticed between early OSMF and advanced OSMF, the variation did not reach statistical significance (p ≥ 0.001). Data suggest that there is a significant loss of PTEN expression in OSMF as compared to normal oral mucosa and that this trend increased from OSMF to OSCC. Thus, alteration of PTEN is likely an important molecular event in OSMF pathogenesis and oral carcinogenesis.

Effect of nickel and chromium exposure on buccal cells of electroplaters

The electroplating industry commonly involves the use of nickel and chromium. An assessment of the genotoxic effects of these metals can be carried out by micronucleus (MN) test in buccal cells. Other nuclear anomalies (NA) observed in buccal cells viz., karyorrhexis, pyknosis and karyolysis are also the indicators of genotoxicity. The current study aims at determining the extent of genotoxic damage in relation to the duration of exposure to nickel and hexavalent chromium via micronuclei induction and other nuclear anomalies. The present investigation included 150 subjects of which 50 individuals with no history of nickel/chromium exposure (Group I) were taken as control, 50 electroplaters exposed to nickel and hexavalent chromium for duration of less than 10 years (Group II) and 50 electroplaters exposed for ≥10 years (Group III) were included. Slides of buccal cells were prepared and the frequency of MN (‰) and NA (‰) were calculated. ANOVA was applied to test significance. Results were considered significant at p < 0.05 and p < 0.001. Group III showed the highest MN frequency (1.08 ± 0.54‰, p < 0.05), karyorrhexis (20.75 ± 6.29, p < 0.05), karyolysis (3.50 ± 1.91, p < 0.001), binucleate (4.75 ± 2.75, p < 0.05) and enucleated cells (5.75 ± 1.70, p < 0.05). Significant increase in frequencies between Group II and III was found as duration of exposure increased. Plasma nickel and chromium levels were also determined which showed a positive correlation with frequency MN and other nuclear abnormalities (p < 0.01).

Cytogenetic alterations in buccal mucosa cells of chewers of areca nut and tobacco

OBJECTIVE

the rationale of the study was to evaluate the cytological alterations especially micronucleus (MN) and other nuclear anomalies in buccal mucosa cells of chewers to understand the genotoxic and clastogenic potential of chewing mixture (containing areca nut and tobacco as main ingredients).

METHODS

the buccal cytome assay involves the examination of epithelial smear to determine micronucleated cell and other nuclear anomalies after the Feulgen plus light green staining. The assay was applied to exfoliated buccal mucosa cells of 262 subjects [non-chewers - 161 and chewers - 101 (includes 20 subjects with OSMF)] and 1000 cells per individual were examined microscopically. Nuclear anomalies were compared among chewers, non-chewers and OSMF subjects and correlated with consumption of quids per day and duration of chewing in years.

RESULTS

MN cells were found significantly (p<0.0001) higher among chewers and OSMF subjects as compared to non-chewers. Further analysis indicated that MN was significantly higher in OSMF subjects with respect to even chewers. Nuclear buds were significantly higher (p<0.0001) in OSMF subjects as compared to chewers as well as non-chewers. Nuclear anomalies viz. binucleated, karyorrhexis and karyolysis were also considerably higher in OSMF subjects as compared to non-chewers.

CONCLUSION

the MN and other nuclear anomalies reflected genetic damage and cytotoxicity, associated with tobacco and areca nut consumption. Further, these data reveal a risk for development of OSMF among chewers of mixture containing areca nut and/or tobacco, as all the OSMF subjects were chewers.

Effects of arecoline on testosterone release in rats

Arecoline is one of the major components of betel nuts, which have been consumed as chewing gum in Southeast Asia. In this study, the effects of arecoline on testosterone (T) secretion were explored. Male rats were injected with human chorionic gonadotropin (hCG, 5 IU/kg) or arecoline (1 microg/kg) plus hCG via a jugular catheter. Blood samples were collected at several time intervals subsequent to the challenge. Rat anterior pituitary was treated with gonadotropin-releasing hormone in vitro with or without arecoline, and then the concentrations of luteinizing hormone (LH) in the medium were measured. Rat Leydig cells were purified by Percoll density gradient centrifugation and incubated with arecoline, hCG, forskolin, 8-bromo-cAMP (8-Br-cAMP), nifedipine, nimodipine, or tetrandrine at 34 degrees C for 1 h. A single intravenous injection of arecoline resulted in an increase of the hCG-induced level of plasma T. Administration of arecoline (10(-8) to 10(-6) M) in vitro increased T production in Leydig cells. The stimulatory effect of arecoline on T release in vitro was enhanced by hCG (0.001 IU/ml), forskolin (10(-6) M), or 8-Br-cAMP (10(-5) M). By contrast, nifedipine, nimodipine, or tetrandrine inhibited the increased T concentrations induced by arecoline. Western blot showed that arecoline increases steroidogenic acute regulatory (StAR) protein expression compared with vehicle. These results suggested that arecoline stimulates testosterone production by acting directly on Leydig cells via mechanisms involving an activation of L-type calcium channels, increasing the activity of 17beta-hydroxysteroid dehydrogenase and enhancing the expression of StAR.

Carotenoids suppress proliferating cell nuclear antigen and cyclin D1 expression in oral carcinogenic models

The purpose of this study was to investigate the chemopreventive effect of carotenoids on proliferating cell nuclear antigen (PCNA) and cyclin D(1) expression in betel (Areca catechu) quid extract (BQE)-induced hamster oral cancer and human KB cell models, respectively. In the in vivo animal study, 41 hamsters were divided into six groups and treated with 0.3 ml of 0.5% 9,10-dimethyl-1,2-benz[a]-anthracene, BQE, alpha-tocopherol, beta-carotene, lycopene, lutein and mixed carotenoids for 12 weeks. After treatment, the pouches were excised and graded using an immunohistochemical assay of PCNA. In the in vitro cell experiment, KB cells were cultured, and the inhibitory effect of carotenoids (beta-carotene, lycopene and lutein) on cell proliferation was evaluated. Cyclin D(1) and PCNA were evaluated in terms of cell differentiation. In the results, most of the animal lesions showed no overexpression of PCNA. However, in dysplastic lesions, PCNA expressions by the beta-carotene, lutein, lycopene, mixed and vitamin E groups were less than that of the control group. In papilloma lesions, PCNA expressions by the beta-carotene, mixed and vitamin E groups were less severe than that of the control group. PCNA expression by the vitamin E-treated group was less severe than that of the control group. No carcinoma was found in the lycopene or mixed groups. In the cell study, all carotenoids exerted a significant inhibitory effect on KB cell proliferation. Although lycopene suppressed KB cell proliferation at the G(0)/G(1) phase with a significant decrease in PCNA expression, beta-carotene and lutein possessed less of an inhibitory effect and even exhibited elevated cell proliferation at the G(2)/M phase. These results indicate that different carotenoids present various suppressive abilities against PCNA and cyclin D(1) expressions in cell proliferation. In conclusion, carotenoids suppressed the carcinogenesis of induced hamster oral cancer and a cancer cell line by acting as a suppressor which inhibited the expressions of PCNA and cyclin D(1).

Molecular genetics of premalignant oral lesions

Oral squamous cell carcinoma (OSCC) is characterized by cellular and subcellular alterations that are associated with a progression towards dedifferentiation and growth. There are several histologically distinct lesions of the oral cavity which have malignant potential. These are leukoplakia, erythroplakia, lichen planus, and submucous fibrosis. These are characterized by a spectrum of chromosomal, genetic, and molecular alterations that they share with each other as well as with the malignant lesions that develop from them. In this review we summarize the investigation of the molecular genetics of each of these lesions and relate them to the alterations, which have been demonstrated in OSCC, to define their location on the continuum of changes, which lead to malignant transformation.

Smoking and smokeless tobacco-associated human buccal cell mutations and their association with oral cancer--a review

Reported herein are the results of a structured literature review that was undertaken to (a) determine if human buccal (mouth) cell changes are associated with smoking and smokeless ("chewing") tobacco, (b) tabulate different buccal cell alterations that have been reported, (c) delineate buccal cell assays that have been used successfully, (d) determine whether buccal cell changes correlate with oral cancer as defined in clinicopathologic investigations, and (e) assess the feasibility of developing a high-throughput buccal cell assay for screening smokers for the early detection of oral cancer. The results of the studies reported herein have established that diverse buccal cell changes are associated with smoking and smokeless tobacco. This review documents also that buccal cells have been collected in a noninvasive manner, and repetitively for serial studies, from different sites of the mouth (e.g., cheek, gum, and tongue) and from normal tissue, preneoplastic lesions (leukoplakia), and malignant tumors. Tobacco-associated genetic mutations and nongenetic changes have been reported; a partial listing includes (a) micronuclei, (b) bacterial adherence, (c) genetic mutations, (d) DNA polymorphisms, (d) carcinogen-DNA adducts, and (e) chromosomal abnormalities. Clinical studies have correlated buccal cell changes with malignant tumors, and some oral oncologists have reported that the buccal cell changes are practical biomarkers. Summarily, the literature has established that buccal cells are useful not only for characterizing the molecular mechanisms underlying tobacco-associated oral cancers but also as exfoliative cells that express diverse changes that offer promise as candidate biomarkers for the early detection of oral cancer.

Establishment and characterization of a tumorigenic cell line from areca quid and tobacco smoke-associated buccal carcinoma

A cell line, TW2.6, has been established from the surgically resected specimen of an untreated primary squamous cell carcinoma of the buccal mucosa from a 48-year-old man who was an areca quid chewer and tobacco smoker. TW2.6 cells exhibited morphological features of keratinocytes and replicated rapidly in culture with a doubling time of 24h. The karyotype showed human chromosomes with high hyperdiploidy and complex rearrangements. Western blotting showed pronounced expression of p53 and moderate expression of p21(CIP1). The baseline expressions of p27(KIP1) and p16(INK4a) were barely detectable. Low levels of Bax and Fas were found in TW2.6 cells but Bcl-2 expression was more readily observed. Mutational analysis of p53 gene revealed an A-->G transition at the second base of codon 220, resulting in amino acid substitution from tyrosine to cysteine in the protein. Functional analysis showed that TW2.6 was unable to activate the p53-specific PUMA promoter. Lipofectamine 2000 and calcium phosphate precipitation technique offer good transfection efficiencies for TW2.6 cells and may be used in future transfection experiments. A xenograft-SCID mouse tumor model was established for TW2.6. Histological examination demonstrated that the engrafted tumors maintained the morphological features of a squamous cell carcinoma. It is thought that the establishment of tumorigenic TW2.6 cell line provides a valuable model for AQ and tobacco smoke-associated buccal carcinoma.

Survivin expression predicts poorer prognosis in patients with areca quid chewing-related oral squamous cell carcinoma in Taiwan

Survivin, a recently characterized novel member of the inhibitor of apoptosis (IAP) family, is not detectable in most differentiated normal adult tissues but is expressed in a wide range of cancer tissues. Its expression in cancer has been correlated with poor prognosis, cancer progression and drug resistance. We immunohistochemically examined the expression of survivin in 62 cases of oral epithelial dysplasia (ED) and 96 cases of oral squamous cell carcinoma (SCC). Cytoplasmic survivin staining was detected in 60 of the 62 (97%) ED specimens and 94 of the 96 (98%) SCC specimens but not in adjacent normal oral mucosal tissues. The labeling index (LI) for survivin protein significantly increased from ED (32.3+/-16.3%) to SCC samples (49.4+/-28.5%) (p<0.001). In addition, the mean LI for ED cases with further malignant transformation into SCC (45.6+/-8.8%) was higher than those without malignant transformation (30.1+/-16.3%) (p=0.008). No significant correlation was found between the survivin expression and the patients' age, sex, oral habit, cancer location, or STNM status in SCC cases. Kaplan-Meier curves showed oral SCC patients with high survivin expression (LI>25%), advanced stage, larger tumor size, or positive lymph node metastasis had significantly shorter overall survival (p=0.014, 0.012, 0.005 and 0.011, respectively by log-rank test) than others. The associations remained significant after adjusting for age. These results indicate that survivin protein expression may be an important early event in oral carcinogenesis and predicts unfavorable prognosis for oral SCC. Furthermore, the unique expression of survivin in cancer cells but not in most normal adult tissues suggests that modulation of survivin protein expression may provide a novel strategy for the therapy of oral SCC.

Cell-mediated immunity and head and neck cancer: with special emphasis on betel quid chewing habit

Betel quid (BQ) chewing is popular in Taiwan, India, and many southeast-Asian countries. BQ chewing has strong association with the risk of oral leukoplakia (OL), oral submucous fibrosis (OSF), and oral cancer (OC). BQ components exhibit genotoxicity and may alter the structure of DNA, proteins and lipids, resulting in production of antigenicity. BQ ingredients are also shown to induce keratinocyte inflammation by stimulating the production of prostaglandins, TNF-alpha, IL-6, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) in keratinocytes. These events may provoke tissue inflammation, early cell-mediated immunity (CMI), and immune surveillance in BQ chewers. However, BQ components also directly affect the functional activities of immunocompotent cells, and moreover tumor cells may hypo-respond to the CMI via diverse mechanisms such as induction of apoptosis of lymphocytes, induction of production of suppressor T cells, downregulation of MHC molecules in tumor cells, etc. Clinically, an alteration in lymphocyte subsets, a decrease in total number of lymphocytes, and a reduction in functional activities of CMI have been observed in isolated peripheral blood mononuclear cells (PBMC) and tumor infiltrated lymphocytes (TIL) in patients with OSF, OL or OC. Adaptation of tumor cells to immune system may promote clonal selection of resistant tumor cells, leading to immune tolerance. Future studies on effects of BQ components on CMI and humoral immunity in vitro and in vivo can be helpful for chemoprevention of BQ-related oral mucosal diseases. To elucidate how virus infection, tobacco, alcohol and BQ consumption, and other environmental exposure affect the immune status of patients with oral premalignant lesions or OC will help us to understand the immunopathogenesis of OC and to develop immunotherapeutic strategies for OC.

Habitual risk factors for head and neck cancer

Chronic tobacco smoking and alcohol consumption are well-established risk factors for the development of squamous cell carcinoma (SCC) of the head and neck. There are, however, a variety of other habitual and culturally based activities that are less commonly seen in the Western world and that are also risks factors for the development of this type of cancer. In this era of globalization, many of these habits have now crossed borders and appear in various areas throughout the world. This article reviews habitual and social risk factors for cancer of the head and neck, excluding smoking and alcohol consumption. These factors include chewing tobacco and snuff, areca nut in its various forms, Khat leaves, and the drinking of Mate.

EBM RATING

D.

Clastogenic effect for cigarette smoking but not areca quid chewing as measured by micronuclei in exfoliated buccal mucosal cells

The objective of this study was to use the micronuclei from exfoliated buccal mucosal cells to investigate the clastogenic effects of areca quid chewing and cigarette smoking, as well as the interaction between the two. The study population was selected from residents of seven villages recruited for a community-cohort study. A total of 141 subjects were recruited based on the regular consumption of cigarettes and betel quid. Salient personal characteristics were collected from interview using a specially designed questionnaire. Micronuclei were scored on Feulgen/fast green-stained smear preparations of exfoliated cells obtained by scraping the surface of the buccal mucosa. There was no significant interaction between the chewing of betel nut and cigarette smoking. Heavy smoking was positively associated with MN frequency, with areca quid chewing negatively associated. A significant positive trend was demonstrated for the relationship between MN frequency and either daily cigarette consumption or cumulative smoking pack-years. By contrast, negative trends were demonstrated for the analogous relationships with areca quid chewing. These results indicate that heavy smoking, but not areca quid chewing, increases MN formation. These findings suggest that the carcinogenesis of the oral cancers induced by areca quid chewing in Taiwan may be through a pathway other than genotoxicity.

Oral cytology assessment by flow cytometry of DNA adducts, aneuploidy, proliferation and apoptosis shows differences between smokers and non-smokers

Oral cytology and morphometric staining is used to identify malignant keratinocytes in oral premalignant or malignant lesions. To detect and to begin to assess changes in oral keratinocytes exposed to tobacco-derived carcinogens, which are at risk for malignant transformation, a novel method is required. The approach uses oral cytology harvested oral keratinocytes analyzed using flow cytometry (FC) for changes in DNA content, damage, cell cycle and apoptosis. Six smoker and six non-smoker oral keratinocytes were evaluated using flow cytometry in the form of laser scanning cytometry (LSC) and laser microdissection (LMD). Among smokers compared to non-smokers, the method detected and assessed DNA damage from tobacco smoke exposure quantifying an enhanced formation of DNA adducts, such as, 8-hydroxy-2'-deoxyguanine (8-OHdG) which creates oxidation lesions and benzo[a]pyrene(B[a]P), which produces a B[a]P)-N2-dG bulky adduct. Increased DNA content, aneuploidy, percentage of cells in synthesis (S) and G(2)+Mitosis (M), and apoptosis were recorded. Tissue and cell controls were used to verify these relationships. Data suggested healthy smokers were at increased risk for malignant transformation of oral keratinocytes because of the changes stated above. Using identical methods, keratinocytes exposed to the tobacco derived carcinogen, B[a]P parallel results obtained from smoke exposure indicating a direct link. Flow cytometric evaluation of oral cytology harvested keratinocytes can be used to measure exposure to tobacco carcinogens, and possibly establish a link to premalignant and malignant transformation before a lesion is noted.

Genotoxic effect of raw betel-nut extract in relation to endogenous glutathione levels and its mechanism of action in mammalian cells

The mutagenic and carcinogenic potency of betel-nut components is well established. This study was undertaken to determine the genotoxic potency of an aqueous extract of raw betel nut (AEBN) in relation to the endogenous glutathione (GSH) level in mouse bone marrow cells (BMC) and human peripheral blood lymphocytes (PBLs), and to find out whether arecoline (ARC), an alkaloid of betel nut, could generate reactive oxygen species (ROS) in these cells. It was observed that AEBN has genotoxic properties, which is further enhanced by depletion of endogenous GSH levels. However, the degree of enhancement varies with the type of parameter and cell system studied. The present data indicate that the generation of ROS by ARC could partially contribute to the induction of chromosomal aberrations (CAs), since the frequency of ARC-induced CAs was reduced either by post-treatment with superoxide dismutase (SOD) or in anoxic conditions. However, the induction of sister chromatid exchanges (SCEs) probably involves p53-dependent changes in cell proliferation and allowing some repair of DNA damage. The extent of damage for each parameter was higher when the mice were exposed to AEBN for 30 days than 5 days. Longer exposure showed higher level of p53 expression in mouse BMC, which could block the damaged cells from proliferation and allow the cells to repair the DNA damage.

The effect of betel nut extract on cell growth and prostaglandin endoperoxide synthase in human epidermoid carcinoma cells

The objective of this study was to find out whether prostaglandin endoperoxide synthase (PHS) involves the action of betel nut extract (BNE) on the growth of oral cancers. Therefore, growth and PHS activity were examined in two human oral carcinoma cell lines (OEC-M1 and KB) and one normal fibroblast cell line (NF) in the presence of increasing BNE concentration. BNE at concentrations above 50 microg/ml significantly inhibited the cell growth of OEC-M1 after 72 h in culture, of KB and NF after 48 h in culture. The IC50 of BNE in OEC-M1, KB and NF at 24 h in culture was about 406, 37.5 and 140 microg/ml respectively. PHS activity in OEC-M1 was significantly increased by low BNE concentrations (50 microg/ml, 114%; 100 microg/ml, 33%; 150 microg/ml, 30%) but significantly reduced at higher BNE concentrations (300 microg/ml, 33%; 500 microg/ml, 61%). The PHS activity in KB was significantly inhibited by BNE and this effect was intensified as concentrations increased (50 microg/ml, 31%; 100 microg/ml, 24%; 150 microg/ml, 43%; 300 microg/ml, 60%; 500 microg/ml, 92%). Similar to that in OEC-M1, the PHS activity in NF was significantly increased at low BNE concentrations (50 microg/ml, 139%; 100 microg/ml, 87%;150 microg/ml, 77%) but reduced at higher concentrations (300 microg/ml, 55%; 500 microg/ml, 72%). The PHS activity in all cell lines was almost completely blocked by indomethacin (5 x 10(-6) M). We conclude that these findings suggest that PHS may be an important biochemical mediator of the effect of BNE on the growth of two human oral carcinoma cell lines.

The oral health consequences of chewing areca nut

Deleterious effects of areca nut on oral soft tissues are published extensively in the dental literature. Its effects on dental caries and periodontal tissues, two major oral diseases, are less well researched. Areca-induced lichenoid lesions mainly on buccal mucosa or tongue are reported at quid retained sites. In chronic chewers a condition known as betel chewer's mucosa, a discoloured areca nut-encrusted change, is often found where the quid particles are retained. Areca nut chewing is implicated in oral leukoplakia and submucous fibrosis, both of which are potentially malignant in the oral cavity. Oral cancer often arises from such precancerous changes in Asian populations. In 1985 the International Agency for Research on Cancer concluded that there is limited evidence to conclude that areca chewing may directly lead to oral cancer. There is, however, new information linking oral cancer to pan chewing without tobacco, suggesting a strong cancer risk associated with this habit. Public health measures to quit areca use are recommended to control disabling conditions such as submucous fibrosis and oral cancer among Asian populations.

Prognostic role of p21WAF1 expression in areca quid chewing and smoking-associated oral squamous cell carcinoma in Taiwan

BACKGROUND

Alterations in p21WAF1 protein expression have been observed in a wide variety of human cancers by immunohistochemistry, and both decreased and increased levels of p21WAF1 protein expression have been shown to correlate with poor prognosis.

METHOD

To examine the relation between p21WAF1 protein expression and prognosis in oral squamous cell carcinomas (SCCs), we performed an immunohistochemical study with antip21WAF1 antibody on 43 oral SCCs. Immunostaining results were then correlated with p53 protein levels, clinicopathological parameters of the tumors and overall patient survival.

RESULTS

Of the 43 patients, 31 (72%) had tumors with positive p21WAF1 nuclear staining and 27 (63%) had tumors with p53 nuclear staining. There was no significant correlation between p21WAF1 and p53 protein expressions and both mutant p53-containing oral SCCs overexpressed p21WAF1 protein. In addition, no significant correlation was found between the p21WAF1 expression and the patients' age, sex, oral habit, cancer location, or primary tumor TNM status at the time of initial presentation. The Kaplan-Meier analysis showed a significant correlation between p21WAF1 protein overexpression and poor patient overall survival (P = 0.049). When p53 and p21WAF1 were evaluated together, the 5-year overall survival was lowest in p53(+)-p21WAF1(+) patients and highest in p53(-)-p21WAF1(-) patients (P = 0.057).

CONCLUSION

Combined evaluation of p21WAF1 and p53 expressions may be useful in estimating the prognosis of patients with oral SCCs in Taiwan.

Paan without tobacco: an independent risk factor for oral cancer

Oral cancer is the second most common cancer in women and the third most common in men in Pakistan. Tobacco is smoked and chewed extensively in Pakistan. Paan is a quid of piper betel leaf that contains areca nut, lime, condiment, sweeteners, and sometimes tobacco, which is also used extensively. We did this study to clarify the independent association of paan and oral cancer. Between July 1996 and March 1998, we recruited biopsy-proven, primary cases of oral squamous-cell carcinoma, from 3 tertiary teaching centers in Karachi, Pakistan, and controls pair-matched for age, gender, hospital and time of occurrence, excluding persons with a past or present history of any malignancy. There were 79 cases and 149 controls. Approximately 68% of the cases were men, 49 years old on average, the youngest being 22 years old and the eldest 80. People with oral submucous fibrosis were 19.1 times more likely to develop oral cancer than those without it, after adjusting for other risk factors. People using paan without tobacco were 9.9 times, those using paan with tobacco 8.4 times, more likely to develop oral cancer as compared with non-users, after adjustment for other covariates. This study identifies an independent effect of paan without tobacco in the causation of oral cancer. Its findings may be of significance in South Asian communities where paan is used, and among health-care providers who treat persons from South Asia.

Clinical and functional staging of oral submucous fibrosis

OBJECTIVE

To investigate the association of location of bands in oral submucous fibrosis and extent of mouth-opening.

DESIGN

Cross-sectional study.

SETTING

University hospital, Pakistan.

SUBJECTS

325 patients who presented with oral submucous fibrosis in Karachi between January 1992 and October 1994, of whom 288 had data sufficient for analysis.

MAIN MEASURES

Location of fibrous bands in the mouth and interincisal distance (mm).

RESULTS

All subjects with labial bands had bands in the fauces, and all but one who had labial bands also had buccal bands. All those with buccal bands also had bands in the fauces. Of those with buccal bands, 42% did not have labial bands. The proportion of patients with bands in all three sites increased from functional stage A (interincisal opening < or = 10 mm) to stage C (interincisal opening > or = 20 mm) with a simultaneous reduction in the proportion of people with bands in one or two sites (X2 = 105, df = 4, P < 0.0001).

CONCLUSIONS

Bands are common at the back of the mouth in mild cases of oral submucous fibrosis and, as the disease increases in severity, are more likely to be found anteriorly as well.

Genotoxic effect of arecoline given either by the peritoneal or oral route in murine bone marrow cells and the influence of N-acetylcysteine

The carcinogenic potentiality of the major alkaloid of betel nut, arecoline (ARC), is well established. This study was undertaken to determine the differences in genotoxic effects of ARC when given by two different routes (oral administration (OA) and intraperitoneal injection (IP)) in mouse bone marrow cells (BMC) since ARC carcinogenicity was observed only when ARC was given orally. The data indicate that ARC-OA induced a higher frequency of cancers, a greater delay in the cell cycle and greater sister chromatid exchanges than ARC-IP. The presence of N-acetyl cysteine along with ARC-OA significantly reduced the effect of ARC.

Anthropometric status and resting metabolic rate in users of the areca nut and smokers of tobacco in rural Sarawak

The areca nut is chewed by many of the world's population, mainly in South and Southeast Asia. Anthropometric data for 458 Sarawaki adults aged over 24 years, measured both in 1990 and in 1996, were examined in relation to use of tobacco and areca nut. Compared to non-smokers, smoking men were significantly taller and slightly (not significantly) thinner in both years, while smoking women were thinner in 1990 and slightly (not significantly) thinner in 1996. In both sexes there was an increase in the mean and range of body mass index (BMI, W/H2) over the 6-year interval. Smoking women showed a significantly smaller increment in BMI after allowing for areca nut use, which was associated with a similar trend, and this finding depended on including areca use in the model. The trend for men was similar. Possible effects of areca use could reflect variation in 'affluence' or conservatism, or appetite suppression. However, resting metabolic rate in 54 men and 70 women aged 24-60 years was associated with areca use. This association appeared to be mediated by the maximum room temperature of the 24 h preceding measurement. In women, a significant curvilinear association of RMR with maximum temperature was found in users of areca nut but not in non-users. In men, RMR was 7% higher (p < 0.05) in users of areca nut than in non-users, after allowing for age, height, weight, the sum of four skinfold thicknesses, and haemoglobin, but the association with maximum temperature was similar in both groups. It is speculated that constituents of areca nut modulate thermoregulatory pathways, resulting in prolonged temperature-dependent and hyperthermic heat production in this population; that males are more responsive to this effect than females; and that by this mechanism, and possibly also through centrally mediated effects on appetite for food, areca use could contribute to long-term variation in energy balance represented by change in BMI.

Loss of heterozygosity of APC and MCC genes in oral squamous cell carcinomas in Taiwan

Loss of heterozygosity (LOH) at adenomatous polyposis coli (APC) and mutated in colon cancer (MCC) genes was investigated in 37 untreated human primary oral squamous cell carcinomas (SCCs) using the polymerase chain reaction. LOH was observed in 14 of 26 (53.8%) heterozygous (informative) patients at APC and 9 of 13 (69.2%) heterozygous patients at MCC> Homozygous deletion of MCC was detected in one patient. Of the 37 patients, 29 were informative at APC or MCC or both; LOH at APC and/or MCC was detected in 68.9% (20/29) of the cases. Ten cases were informative for both genes; LOH at both loci was found in only three of these cases. LOH at the APC and/or MCC was found in both early and advanced stages of oral SCCs. No significant correlation was observed between LOH at the APC and/or MCC locus and the patients' tobacco/betel quid consumption, tumour location, TNM status, or histological differentiation. These results suggest that LOH at the APC and/or MCC may be an early event and may play a role in the pathogenesis of human oral SCCs in Taiwan.

Increased severity of oral submucous fibrosis in young Pakistani men

OBJECTIVE

To investigate the influence of age and sex on the incidence of severe oral submucous fibrosis (mouth opening 15 mm or less).

DESIGN

Case (severe disease) control (mild disease) study.

SETTING

University hospital, Pakistan.

SUBJECTS

147 patients with severe (mouth opening 15 mm or less) and 83 with mild disease (mouth opening 20 mm or more).

MAIN MEASURES

Influence of sex and age on severity of oral submucous fibrosis.

RESULTS

Men were twice as likely as women to have severe disease (odds ratio (OR) 2.0, 95% confidence interval (CI) of OR 1.15 to 3.47, P=0.02). Men in the 20-39 year age group were 4.8 times as likely as women to have severe disease (OR 5.8, 95% CI 2.15 to 15.5, P=0.00004). Men aged 40 years or more were 40% less likely to have severe disease than women (OR 0.6, 95% CI 0.19 to 1.88, P=0.39).

CONCLUSIONS

Smoking increases the carcinogenic potential of submucous fibrosis. As men in this population smoke more than women, men with severe oral submucous fibrosis may develop oral cancer and die younger. Alternatively, young men may consume more areca nut than women.

The relapse patterns and outcome of postoperative recurrent tongue cancer

PURPOSE

The relapse patterns and salvage treatment results for patients who developed locoregional recurrence after surgery for squamous cell carcinoma of the tongue were retrospectively analyzed.

MATERIALS AND METHODS

Between April 1986 and January 1995, 77 cases with recurrent squamous cell carcinoma of the tongue were evaluated. Most of them were males in the early stages of initial disease. Although the surgical margins were negative in most cases (67 of 77), relapse eventually occurred. The relapse patterns showed 15 patients with primary recurrence, 45 patients with regional neck lymph node (LN) relapse, and 17 patients with relapse in both sites.

RESULTS

Salvage treatment was given to most of the patients, but their median survival time was only 9 months. Survival data were analyzed and compared with different types of relapse patterns, salvage treatments, disease-free intervals, age, and sex. In univariate analysis, the neck LN relapse and shorter relapse-free interval (< 6 months) were poor prognostic factors (P < .05), and surgical treatment showed a trend for better salvage results (P = .0575). In multivariate analysis, patients with neck LN relapse had the worst outcome (P < .05).

CONCLUSIONS

Recurrence of tongue cancer is not uncommon, but there are little data in literature regarding the prognosis. Although this study showed poor salvage results, various prognoses could be predicted on the bases of the different relapse patterns and salvage methods.

Oral stent as treatment adjunct for oral submucous fibrosis

Oral submucous fibrosis is a chronic inflammatory disease that results in progressive juxtaepithelial fibrosis of the oral soft tissues that can cause increasing difficulty in chewing, swallowing, speaking, and mouth opening. Many treatment regimens for oral submucous fibrosis have been proposed to alleviate the signs and symptoms of the disorder. In severe cases, surgical intervention is the only treatment modality, but relapse is a major problem. This article describes the use of an oral stent as an adjunct to surgery to prevent relapse.

Acculturation as a risk factor for chronic disease among Cambodian refugees in the United States

Although the concept of acculturation originated within anthropology, in recent years it has assumed a prominent role within epidemiology as a risk factor for chronic disease. However, these studies often consider acculturation in structural terms, reflected in differences between groups assumed to lie along the same continuum, all moving in the same direction toward greater acculturation to the values and behaviors of the dominant society. This paper addresses how acculturation should be conceptualized when examining it as a potential risk factor for chronic disease and how it should be measured so that it becomes both theoretically and clinically meaningful. Four case studies of Cambodian refugees of San Diego, California are used to illustrate the following: (1) the importance of integrating an acculturation-as-process perspective with an acculturation-as-structure perspective; (2) viewing acculturation as both individual and group experience of conflict and negotiation between two systems of behavior and belief; (3) measuring it longitudinally and as narrative; and (4) understanding that rather than being an inherent health risk, it may also promote health by creating access to certain forms of health care unavailable in the country of origin and by contributing to the abandonment of risky health-related behaviors and the adoption of behaviors that promote good health.

Observations on the effect of areca nut extracts on oral fibroblast proliferation

The effects of aqueous extracts of raw, baked and boiled areca nuts were tested on cultured human buccal mucosa fibroblasts. Cells were exposed to extract concentrations of 0, 50, 100, 150, 300 and 500 micrograms/ml. The arecoline and arecaidine content was determined in the extracts with HPLC and raw nut contained 5.5% m/m, baked nut 6.6% m/m and boiled nut 7.1% m/m. Extract concentrations of 50 to 150 micrograms/ml inhibited cell growth in a concentration-dependent manner but did not lead to total cell death during a 7 day period. However, total cell death did occur with concentrations of 300 and 500 micrograms/ml. It is concluded that areca nut extract is toxic to cultured fibroblasts and inhibits their proliferation in a concentration-dependent manner.