Tea consumption: fluid intake and bladder cancer risk in Southern Taiwan

The Association between Tea Consumption and Bladder Cancer Risk Based on the Bladder Cancer Epidemiology and Nutritional Determinants (BLEND) International Consortium

OBJECTIVES

Evidence regarding the association between tea consumption and bladder cancer (BC) risk is inconsistent. This study aimed to increase our knowledge of the association by using international data from the Bladder Cancer Epidemiology and Nutritional Determinants Consortium.

METHODS

Individual data on 2,347 cases and 6,871 controls from 15 case-control studies with information on black, green, herbal, or general tea was pooled. The association was estimated using multilevel multivariable logistic regression analysis adjusted for multiple (non-)dietary factors.

RESULTS

Association between tea consumption and BC risk was observed (odds ratio, OR = 0.72, 95% confidence interval, 95% CI = 0.65-0.80) compared to non-tea drinkers. Stratified analyses based on gender and smoking status yielded similar results. Stratified analysis showed no significant association between black or green tea consumption and BC risk across models, while herbal tea consumption was linked to a reduced BC risk (OR = 0.59, 95% CI = 0.36-0.96). As daily tea consumption increased within a suitable range (<5.67 cups/day), BC risk decreased.

CONCLUSIONS

Camellia sinensis tea showed no association with BC risk, while herbal tea was inversely linked to BC incidence. Despite some significant findings in the selected strata, further studies are required to clarify the underlying mechanisms.

Tea Drinking and the Risk of Carcinoma of the Urinary Bladder: A Meta-Analysis

Objective

For evaluation of the correlation between tea drinking and the risk of carcinoma of the urinary bladder.

Methods

By searching PubMed, Embase, and Cochrane Library databases, the original studies on tea drinking and carcinoma of the urinary bladder risk were collected, the data were extracted, and meta-analysis package 5.2-0 of R language was used for meta-analysis.

Results

This study contained 11 researches, composed of 7686 patients and 10320 controls. Tea drinking was not linked to carcinoma of the urinary bladder risk (OR:1.02, 95%CI: 0.95-1.11).

Conclusion

Tea drinking may not be linked to carcinoma of the urinary bladder, but more definitive results are needed from higher-quality trials.

A data mining approach to investigate food groups related to incidence of bladder cancer in the BLadder cancer Epidemiology and Nutritional Determinants International Study

At present, analysis of diet and bladder cancer (BC) is mostly based on the intake of individual foods. The examination of food combinations provides a scope to deal with the complexity and unpredictability of the diet and aims to overcome the limitations of the study of nutrients and foods in isolation. This article aims to demonstrate the usability of supervised data mining methods to extract the food groups related to BC. In order to derive key food groups associated with BC risk, we applied the data mining technique C5.0 with 10-fold cross-validation in the BLadder cancer Epidemiology and Nutritional Determinants study, including data from eighteen case-control and one nested case-cohort study, compromising 8320 BC cases out of 31 551 participants. Dietary data, on the eleven main food groups of the Eurocode 2 Core classification codebook, and relevant non-diet data (i.e. sex, age and smoking status) were available. Primarily, five key food groups were extracted; in order of importance, beverages (non-milk); grains and grain products; vegetables and vegetable products; fats, oils and their products; meats and meat products were associated with BC risk. Since these food groups are corresponded with previously proposed BC-related dietary factors, data mining seems to be a promising technique in the field of nutritional epidemiology and deserves further examination.

Dairy Product Consumption and Bladder Cancer Risk: A Meta-Analysis

To explore the potential relationship between dairy product consumption and bladder cancer risk, we retrieved eligible studies published up to March 15, 2018, via online database search and manual review of the selected articles. Summary relative risk (RR) estimates were calculated using random-effects models based on high to low intake values. Inter-study heterogeneity was explored using stratified analyses of study design, geographic region, or whether studies adjusted for the confounders age, sex, body mass index, smoking, and education level. We extracted data from 16 studies on milk (5,193 subjects) and 10 studies on dairy products (20,434 subjects). The total study population included 220,952 individuals. Dairy product intake and bladder cancer risk were significantly associated, and milk intake and bladder cancer risk more so. Stratified analysis revealed that the trend was more pronounced in case-control studies, and in studies with impact factor <3 and in Asia. The relationship was confirmed after adjusting for sex and Newcastle-Ottawa Scale score of 7 and 8. Our study shows an inverse association between milk consumption and bladder cancer risk.

Impact of alcohol consumption on the risk of developing bladder cancer: a systematic review and meta-analysis

BACKGROUND

Epidemiologic studies that investigated alcohol consumption in relation to the risk of bladder cancer (BCa) have demonstrated inconsistent results. We conducted a systematic review and meta-analysis of the literature to investigate the association of alcohol including different types of alcoholic beverages consumption with the risk of BCa.

MATERIALS AND METHODS

A systematic search of Web of Science, Medline/PubMed and Cochrane library was performed in May 2018. Studies were considered eligible if they assessed the risk of BCa due to alcohol consumption (moderate or heavy dose) and different types of alcoholic beverages (moderate or heavy dose) in multivariable analysis in the general population (all genders, males or females) or compared with a control group of individuals without BCa.

STUDY DESIGN

observational cohorts or case-control.

RESULTS

Sixteen studies were included in this meta-analysis. Moderate and heavy alcohol consumption did not increase the risk of BCa in the entire population. Sub-group and sensitivity analyses revealed that heavy alcohol consumption increased significantly the risk of BCa in the Japanese population, RR 1.31 (95% CI 1.08-1.58, P < 0.01) in the multivariable analysis, and in males RR of 1.50 (95% CI 1.18-1.92, P < 0.01), with no significant statistical heterogeneity. Moreover, heavy consumption of spirits drinks increased the risk of BCa in males, RR 1.42 (95% CI 1.15-1.75, P < 0.01).

CONCLUSION

In this meta-analysis, moderate and heavy alcohol consumption did not increase the risk of bladder cancer significantly. However, heavy consumption of alcohol might increase the risk of BCa in males and in some specific populations.

The association between coffee consumption and bladder cancer in the bladder cancer epidemiology and nutritional determinants (BLEND) international pooled study

Background

Inconsistent results for coffee consumption and bladder cancer (BC) risk have been shown in epidemiological studies. This research aims to increase the understanding of the association between coffee consumption and BC risk by bringing together worldwide case–control studies on this topic.

Methods

Data were collected from 13 case–control comprising of 5,911 cases and 16,172 controls. Pooled multivariate odds ratios (ORs), with corresponding 95% confidence intervals (CIs), were obtained using multilevel logistic regression models. Furthermore, linear dose–response relationships were examined using fractional polynomial models.

Results

No association of BC risk was observed with coffee consumption among smokers. However, after adjustment for age, gender, and smoking, the risk was significantly increased for never smokers (ever vs. never coffee consumers: OR_model2 1.30, 95% CI 1.06–1.59; heavy (> 4 cups/day) coffee consumers vs. never coffee consumers: OR_model2 1.52, 95% CI 1.18–1.97, p trend = 0.23). In addition, dose–response analyses, in both the overall population and among never smokers, also showed a significant increased BC risk for coffee consumption of more than four cups per day. Among smokers, a significant increased BC risk was shown only after consumption of more than six cups per day.

Conclusion

This research suggests that positive associations between coffee consumption and BC among never smokers but not smokers.

Milk and Dairy Product Consumption and Bladder Cancer Risk: A Systematic Review and Meta-Analysis of Observational Studies

Some studies have reported that milk and dairy product consumption reduces bladder cancer incidence, whereas others have reported null or opposite findings. This meta-analysis of 26 cohort and case-control studies has been conducted to pool the risk of the association between milk and dairy products and bladder cancer. A systematic search in MEDLINE, EMBASE, and the Web of Science (from inception to 30 April 2018) was conducted. Random-effects models were used to compute pooled estimates of RR for high or medium compared with low consumption of milk and dairy. Sensitivity analyses were conducted. Subgroup analyses were performed based on type of dairy, gender, geographic location, and type of study design. Random-effects meta-regression was used to evaluate other confounding factors. Overall, medium compared with low consumption was associated with lower pooled risk of bladder cancer for total dairy products (RR = 0.90; 95% CI: 0.81, 0.98), milk (RR = 0.90; 95% CI: 0.82, 0.98), and fermented dairy products (RR = 0.87; 95% CI: 0.79, 0.96). The inverse association for milk consumption was stronger in Asians (RR = 0.79; 95% CI: 0.59, 0.98) and in cohort design studies (RR = 0.85; 95% CI: 0.71, 0.99). Moreover, high compared with low consumption was significantly associated with a lower pooled risk for milk (RR = 0.89; 95% CI: 0.81, 0.98) and fermented dairy products (RR = 0.78; 95% CI: 0.61, 0.94). However, high compared with low consumption of whole milk was significantly associated with a higher risk (RR = 1.21; 95% CI: 1.04, 1.38). The statistical heterogeneity was considerable. In conclusion, the present meta-analysis suggests a decreased risk of bladder cancer associated with medium consumption of total dairy products and with medium and high consumption of milk and fermented dairy products. An increased risk of bladder cancer was observed with high consumption of whole milk. Interpretations of the results should be made with caution. This review was registered at www.crd.york.ac.uk/prospero as CRD42018097020.

Alcohol consumption and bladder cancer risk with or without the flushing response: The Japan Public Health Center-based Prospective Study

The association between alcohol consumption and bladder cancer risk has been insufficiently investigated in East Asian populations, who frequently have the inactive enzyme for metabolizing acetaldehyde. Given that acetaldehyde associated with alcohol consumption is assessed as a carcinogen, consideration of differences in acetaldehyde exposure would aid accuracy in assessing the bladder cancer risk associated with alcohol consumption. Here, we conducted a population-based cohort study in Japan to examine this association, including information on the flushing response as a surrogate marker of the capacity of acetaldehyde metabolism. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using multivariate Cox proportional hazard models. During follow up from 1990 through 2012 for the 95,915 subjects (45,649 men and 50,266 women, aged 40-69 years), 354 men and 110 women were newly diagnosed with bladder cancer. No significant association between alcohol consumption and bladder cancer risk was observed in the overall analysis. Among male flushers, HRs were 1.04 (95% CI 0.70-1.54), 1.67 (1.16-2.42), 1.02 (0.62-1.67) and 0.63 (0.33-1.20) for alcohol consumption of 1-150, 151-300, 301-450, >450 g/week of pure ethanol compared with non-drinkers and occasional drinkers, respectively, indicating an inverted U-shaped association between alcohol consumption and bladder cancer risk. In contrast, no significant association was identified among male non-flushers. The marginally significant interaction between alcohol consumption and the flushing response (p for interaction = 0.083) may support our hypothesis that acetaldehyde derived from alcohol consumption is associated with bladder cancer risk. A prospective study considering polymorphisms of genes involved in acetaldehyde metabolism is warranted.

Oolong tea: A critical review of processing methods, chemical composition, health effects, and risk

Oolong tea (OT) is a traditional Chinese tea (Camellia sinensis) and is especially popular in south China. This review is to comprehensively summarize the miscellaneous research that has been done towards to the processing, phytochemistry, health benefit, and risk of OT. These literatures were carried out not only from different electronic databases but also from text books written in English, Japanese, and Chinese, including those traditional records tracing back to the Tang Dynasty (A.D. 618-907). The full process OT producing is depicted below in this review. The phytochemistry of OT has been comprehensively investigated. More than 100 chemical compositions have been isolated and identified. In health benefit, OT performs outstandingly in reducing obesity and controlling diabetes explained by modern pharmacological studies. (-)-Epigallocatechin-3-gallate (6) in OT prevention of cancerous cells developing. OT can also improve and reduce on heart and vascular disease, protect teeth and bone, function as anti-oxidative and antibacterial agents. This review also mentioned the risk, summarized briefly on various forms of toxicity and harmful associated with OT. In short, this review can provided a natural product library of OT, gave inspirations for further new garden systems, designed idea on quality, bioactivity-oriented screening. In addition, it is suggested more scientists and education is necessary to guarantee the stability and safety of drinking OT.

Tea Consumption and Risk of Bladder Cancer: A Dose-Response Meta-Analysis

Background and Objective: Controversial results of the association between tea (black tea, green tea, mate, and oolong tea) consumption and risk of bladder cancer were reported among epidemiological studies. Thus, we performed a meta-analysis of observational studies to investigate the association. Methods: We searched the PubMed and Embase for studies of tea consumption and bladder cancer that were published in any language up to March, 2016. Cohort or case-control studies were included in the meta-analysis. All statistical analyses were performed in Stata 12.0 software. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the relationship between tea consumption and risk of bladder cancer. Results: Totally, 25 case-control studies (15 643 cases and 30 795 controls) and seven prospective cohort studies (1807 cases and 443 076 participants) were included. The meta-analysis showed that tea consumption was not significantly associated with bladder cancer risk (OR = 0.96, 95% CI 0.86-1.06) (in a comparison of highest vs. lowest category). No non-linearity association was observed between tea consumption and bladder cancer risk (P = 0.51 for non-linearity). Specific analysis for black tea, green tea, and mate yielded similar results. The dose-response analysis showed the summary OR for an increment of 1 cup/day of tea consumption was 1.01 (95% CI 0.97-1.05). Conclusion: Results based on current meta-analysis indicated that no significant association was observed between tea consumption and risk of bladder cancer.

Gallic Acid Content in Taiwanese Teas at Different Degrees of Fermentation and Its Antioxidant Activity by Inhibiting PKCδ Activation: In Vitro and in Silico Studies

Teas can be classified according to their degree of fermentation, which has been reported to affect both the bioactive components in the teas and their antioxidative activity. In this study, four kinds of commercial Taiwanese tea at different degrees of fermentation, which include green (non-fermented), oolong (semi-fermented), black (fully fermented), and Pu-erh (post-fermented) tea, were profiled for catechin levels by using high performance liquid chromatography (HPLC). The result indicated that the gallic acid content in tea was directly proportional to the degree of fermentation in which the lowest and highest gallic acid content were 1.67 and 21.98 mg/g from green and Pu-erh tea, respectively. The antioxidative mechanism of the gallic acid was further determined by in vitro and in silico analyses. In vitro assays included the use of phorbol ester-induced macrophage RAW264.7 cell model for determining the inhibition of reactive oxygen species (ROS) production, and PKCδ and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit (p47) activations. The results showed that only at a concentration of 5.00 μM could gallic acid significantly (p < 0.05) reduce ROS levels in phorbol ester-activated macrophages. Moreover, protein immunoblotting expressed similar results in which activations of PKCδ and p47 were only significantly (p < 0.05) attenuated by 5.00 μM treatment. Lastly, in silico experiments further revealed that gallic acid could block PKCδ activation by occupying the phorbol ester binding sites of the protein.

International pooled study on diet and bladder cancer: the bladder cancer, epidemiology and nutritional determinants (BLEND) study: design and baseline characteristics

Background

In 2012, more than 400,000 urinary bladder cancer cases occurred worldwide, making it the 7^th most common type of cancer. Although many previous studies focused on the relationship between diet and bladder cancer, the evidence related to specific food items or nutrients that could be involved in the development of bladder cancer remains inconclusive. Dietary components can either be, or be activated into, potential carcinogens through metabolism, or act to prevent carcinogen damage.

Methods/design

The BLadder cancer, Epidemiology and Nutritional Determinants (BLEND) study was set up with the purpose of collecting individual patient data from observational studies on diet and bladder cancer. In total, data from 11,261 bladder cancer cases and 675,532 non-cases from 18 case–control and 6 cohort studies from all over the world were included with the aim to investigate the association between individual food items, nutrients and dietary patterns and risk of developing bladder cancer.

Discussion

The substantial number of cases included in this study will enable us to provide evidence with large statistical power, for dietary recommendations on the prevention of bladder cancer.

Coffee consumption and bladder cancer: a meta-analysis of observational studies

Controversial results of the association between coffee consumption and bladder cancer (BC) risk were reported among epidemiological studies. Therefore, we conducted this meta-analysis to clarify the association. Relevant studies were identified according to the inclusion criteria. Totally, 34 case-control studies and 6 cohort studies were included in our meta-analysis. The overall odds ratio (OR) with 95% confidence interval (CI) between coffee consumption and BC risk was 1.33 (95% CI 1.19 to 1.48). The summary ORs of BC for an increase of 1 cup of coffee per day were 1.05 (95% CI 1.03 to 1.06) for case-control studies and 1.03 (95% CI 0.99 to 1.06) for cohort studies. The overall ORs for male coffee drinkers, female coffee drinkers and coffee drinkers of both gender were 1.31 (95% CI: 1.08 to 1.59), 1.30 (95% CI: 0.87 to 1.96) and 1.35 (95% CI: 1.20 to 1.51). Compared with smokers (OR = 1.24, 95% CI: 0.91 to 1.70), non-smokers had a higher risk (OR = 1.72, 95% CI: 1.25 to 2.35) for BC. Results of this meta-analysis suggested that there was an increased risk between coffee consumption and BC. Male coffee drinkers and non-smoking coffee drinkers were more likely to develop BC.

Bladder cancer epidemiology and genetic susceptibility

Bladder cancer is the most common malignancy of the urinary system. The incidence of bladder cancer of men is higher than that of women (approximately 4:1). Here, we summarize the bladder cancer-related risk factors, including environmental and genetic factors. In recent years, although the mortality rate induced by bladder cancer has been stable or decreased gradually, the public health effect may be pronounced. The well-established risk factors for bladder cancer are cigarette smoking and occupational exposure. Genetic factors also play important roles in the susceptibility to bladder cancer. A recent study demonstrated that hereditary non-polyposis colorectal cancer is associated with increased risk of bladder cancer. Since 2008, genome-wide association study (GWAS) has been used to identify the susceptibility loci for bladder cancer. Further gene-gene or gene-environment interaction studies need to be conducted to provide more information for the etiology of bladder cancer.

Evaluation of a bladder cancer cluster in a population of criminal investigators with the Bureau of Alcohol, Tobacco, Firearms and Explosives-part 1: the cancer incidence

This study investigated a bladder cancer cluster in a cohort of employees, predominately criminal investigators, participating in a medical surveillance program with the United States Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) between 1995 and 2007. Standardized incidence ratios (SIRs) were used to compare cancer incidences in the ATF population and the US reference population. Seven cases of bladder cancer (five cases verified by pathology report at time of analysis) were identified among a total employee population of 3,768 individuals. All cases were white males and criminal investigators. Six of seven cases were in the 30 to 49 age range at the time of diagnosis. The SIRs for white male criminal investigators undergoing examinations were 7.63 (95% confidence interval = 3.70-15.75) for reported cases and 5.45 (2.33-12.76) for verified cases. White male criminal investigators in the ATF population are at statistically significant increased risk for bladder cancer.

A meta-analysis of tea consumption and the risk of bladder cancer

OBJECTIVE

Previous studies on the association between tea consumption and bladder cancer risk have only illustrated contradictory results. The role of tea in bladder carcinogenesis still remains conflicting. In order to illustrate the potential relationship between tea consumption and bladder cancer, a meta-analysis of case-control and cohort studies was conducted.

METHODS

Eligible studies were retrieved via both computerized searches and review of references. Stratified analyses on types of tea, gender, study design, ethnicity and smoking status were performed. Fixed- or random-effect models were used to summarize the estimates of OR with 95% CIs.

RESULTS

Seventeen studies were eligible for our analysis. No statistical significance was detected between tea consumption and bladder cancer risk when comparing the highest with the lowest intake of tea (OR = 0.825, 95% CI 0.652-1.043). In the subgroup of green tea, we observed it illustrated a protective effect on bladder cancer (OR = 0.814, 95% CI 0.678-0.976).

CONCLUSION

Our analysis indicated that green tea may have a protective effect on bladder cancer in Asian people. Further studies need to be conducted to better clarify the biological mechanisms.

Tea consumption and risk of bladder cancer: a meta-analysis

Background

Tea consumption has been reported to be associated with an decreased risk of several types of cancers. However, the results based on epidemiological studies on the association of tea consumption with bladder cancer were inconsistent. This meta-analysis was undertaken to evaluate the relationship between tea consumption and bladder cancer risk.

Methods

Eligible studies were retrieved via both computer searches and review of references. The summary relative risk (RR) with 95% confidence interval (CI) was calculated.

Results

Twenty three studies met the inclusion criteria of the meta-analysis. No association with bladder cancer was observed in either overall tea consumption group (OR =0.94, 95% CI 0.85-1.04) or subgroups stratified by sex, study design, geographical region or tea types.

Conclusions

Our findings did not support that tea consumption was related to the decreased risk of bladder cancer.

Milk and dairy consumption and risk of bladder cancer: a meta-analysis

OBJECTIVE

To explore potential relations between the intake of milk or dairy products and the risk of bladder cancer.

METHODS

Eligible studies published up to May 2011 were retrieved via both computer searches and manual review of references. Random-effects models were used to calculate summary relative risk estimates (SRRE) based on high-contrast to low-intake values. Sensitivity and influence analyses were conducted, and heterogeneity among study results was explored through stratified analyses by study design, gender, geographic region, year of publication, or whether or not adjustment for several confounders (ie, age, gender, body mass index, smoking, and total energy intake).

RESULTS

We extracted data from 14 studies on milk (involving 4879 cases) and 6 studies on dairy products (3087 cases). The total study population was up to 324,241 individuals. Overall, there was no significant association between milk intake and bladder cancer (SRRE 0.89, 95% CI 0.77-1.02). However, an inverse association was found in the United States (SRRE 0.88, 95% CI .79-.99). In addition, no significant association was observed between consumption of dairy products and risk of bladder cancer (SRRE 0.95, 95% CI .71-1.27), though an inverse association was detected in the Japanese population (SRRE 0.56, 95% CI .40-.80).

CONCLUSION

There appears to be enough evidence to support the null hypothesis. The overall result was not statistically significant. The findings of this meta-analysis are not supportive of an independent relationship between the intake of milk or dairy products and the risk of bladder cancer. However, these findings are based on limited research. Further efforts should be made to confirm these findings.

Milk consumption and bladder cancer risk: a meta-analysis of published epidemiological studies

Studies investigating the association of milk consumption with bladder cancer risk have reported inconsistent findings. We conducted a meta-analysis of published cohort and case-control studies to pool the risk estimates of the association between milk intake and bladder cancer. We quantified associations with bladder cancer using meta-analysis of odds ratio (OR) associated with the highest vs. the lowest category of milk intake using fixed- or random-effect models depending on the heterogeneity of effects among studies. Nineteen cohort and case-control studies were eligible for inclusion. High milk intake was significantly associated with decreased risk of bladder cancer (OR, 0.84; 95% CI, 0.71-0.97) when comparing the highest with the lowest category of milk intake. The inverse association was stronger in Asia (OR, 0.60; 95% CI, 0.40-0.81) than North America (OR, 0.89; 95% CI, 0.76-1.03), and no association was observed in Europe (OR, 1.05; 95% CI, 0.85-1.26). This relationship also varied significantly by specific dairy products. Our results suggest that milk may be related to the reduction of bladder cancer risk. Further studies need to clarify the biological mechanisms.

Risks and benefits of dietary isoflavones for cancer

A high intake of fruits and vegetables is associated with a lower risk of cancer. In this context, considerable attention is paid to Asian populations who consume high amounts of soy and soy-derived isoflavones, and have a lower risk for several cancer types such as breast and prostate cancers than populations in Western countries. Hence, interest focuses on soyfoods, soy products, and soy ingredients such as isoflavones with regard to their possible beneficial effects that were observed in numerous experiments and studies. The outcomes of the studies are not always conclusive, are often contradictory depending on the experimental conditions, and are, therefore, difficult to interpret. Isoflavone research revealed not only beneficial but also adverse effects, for instance, on the reproductive system. This is also the case with tumor-promoting effects on, for example, breast tissue. Isoflavone extracts and supplements are often used for the treatment of menopausal symptoms and for the prevention of age-associated conditions such as cardiovascular diseases and osteoporosis in postmenopausal women. In relation to this, questions about the effectiveness and safety of isoflavones have to be clarified. Moreover, there are concerns about the maternal consumption of isoflavones due to the development of leukemia in infants. In contrast, men may benefit from the intake of isoflavones with regard to reducing the risk of prostate cancer. Therefore, this review examines the risks but also the benefits of isoflavones with regard to various kinds of cancer, which can be derived from animal and human studies as well as from in vitro experiments.

Nutrition and nonmelanoma skin cancers

The incidence of nonmelanoma skin cancer is increasing every year. Basal cell carcinoma and squamous cell carcinoma are the two major types of nonmelanoma skin cancer. Among other factors, understanding the potential role of nutrients in the development, progression, and treatment of nonmelanoma skin cancer is critical. This contribution provides a review of the nutrients that have been more extensively investigated in the literature with regard to nonmelanoma skin cancer, including dietary fats, retinol, carotenoids, vitamin C, vitamin D, vitamin E, selenium, copper, iron, zinc, green tea, and black tea.

Green tea polyphenol suppresses tumor invasion and angiogenesis in N-butyl-(-4-hydroxybutyl) nitrosamine-induced bladder cancer

BACKGROUND

Green tea polyphenol (GTP) suppresses malignancy in bladder cancer cell lines. However, the detail of its anti-carcinogenic effect in vivo is not fully understood. This study investigated the effect of GTP on bladder tumor size and angiogenesis in mice given N-butyl-(-4-hydroxybutyl) nitrosamine (BBN), with and without GTP.

METHODS

Eight-week-old female C3H/He mice were treated with and without 0.05% BBN solution for 14 or 24 weeks. In addition, they were also treated with and without 0.5% GTP solution for the same periods. Histopathological diagnosis was established using hematoxylin and eosin staining, and microvessel density (MVD) was estimated by counting CD34- and von Willebrand factor-positive vessels in the tumor area.

RESULTS

At 14 weeks, cancer cells were detected in BBN and BBN+GTP mice [5/14 (35.7%) and 3/14 (21.4%), respectively, p=0.678]. At 24 weeks, the incidence of cancer cells was also similar between the groups (BBN+GTP: 61.9% vs. BBN: 82.6%; p=0.179). However, the frequency of invasive tumors in BBN+GTP mice was significantly lower (23.8%; p=0.030) than in those given BBN alone (65.2%). Tumor volume and MVD of intratumoral and stromal region in the BBN+GTP group were also significantly lower than in BBN mice.

CONCLUSION

The results showed that GTP had no anti-carcinogenic effect, but inhibited tumor growth and invasion in mice with established bladder cancer, at least in part through the regulation of angiogenesis. Our data suggest that GTP seems to suppress tumor development in bladder cancer.

A thought on the biological activities of black tea

Tea is the most widely used ancient beverage in the world and black tea possesses many biological effects on the organisms. It acts as an effective antioxidant because of its free radical-scavenging and metal-chelating ability. Due to this, it is active against inflammation, clastogenesis, and several types of cancer. Tea reduces DNA damage and mutagenesis due to oxidative stress or the presence of pro-mutagens through antioxidant function, blocking activation pathways of mutagens, suppressing transcription of enzymes involved etc. Inhibition of low-density lipoprotein (LDL) peroxidation, suppression of fatty acid synthase etc., suggest that tea may have a role in preventing cardiovascular diseases. Some epidemiological studies support the protective role of black tea against cardiovascular diseases but some do not. Besides, black tea has beneficial effects on the gastrointestinal tract; it affects motility, absorption, microflora etc., by influencing the hormonal balance and antioxidant function black tea improves bone mineral density. It is also antiviral due to its enzyme-inhibiting and receptor-blocking properties. Although its role in cancers of the gastrointestinal tract, liver, and prostate is confirmed, its effect against urinary tract cancer is uncertain and further studies are required. Apart from these, excess consumption may lead to the formation of a stained pellicle layer on teeth, which is difficult to eliminate, inhibits trypsin, influences mineral absorption, causes convulsions etc. Excess caffeine intake may have adverse effects on selected organs as reported in studies on some organisms. These reports indicate that there is a wide scope of further research for the efficient use of black tea active conserves/isolates to reap health benefits.

Age-related risk of mortality from bladder cancer in diabetic patients: a 12-year follow-up of a national cohort in Taiwan

BACKGROUND

To compare bladder cancer mortality between diabetic patients and the general population.

MATERIALS AND METHODS

Yearly sex-specific mortality rates for age 25-64, 65-74, and > or =75 years in Taiwanese general population for 1995-2006 were calculated; 113,347 diabetic men and 131,573 diabetic women aged > or =25 years recruited in 1995-1998 were followed prospectively.

RESULTS

In the general population, 4,943 men and 2,291 women died of bladder cancer, and aging was associated with increased risk. Although the trend of crude mortality was increasing in either sex, the trend of age-standardized rates had been steady. The average crude and age-standardized mortality rates were 5.35 and 5.98 (per 100,000 population), respectively, for men; and were 2.63 and 3.02 for women. A total of 224 diabetic men and 126 diabetic women died of bladder cancer with crude mortality of 26.0 and 11.9 per 100,000 person-years, respectively. The relative risk of bladder cancer mortality (95% confidence interval) for diabetic patients was 2.18 (1.75-2.72), 2.50 (2.06-3.04), and 5.95 (4.57-7.74), in men, and 1.34 (0.96-1.89), 2.48 (1.92-3.19), and 7.44 (5.46-10.15), in women, for ages > or =75, 65-74, and 25-64 years, respectively.

CONCLUSIONS

Diabetic patients had a higher risk of bladder cancer mortality, which is more remarkable in the younger population.

Cultured milk, yogurt, and dairy intake in relation to bladder cancer risk in a prospective study of Swedish women and men

BACKGROUND

Findings from epidemiologic studies of the effect of dairy foods (mainly milk) on the risk of bladder cancer have been inconsistent.

OBJECTIVE

We aimed to examine the association between the intake of cultured milk and other dairy foods and the incidence of bladder cancer in a prospective, population-based cohort.

DESIGN

We prospectively followed 82,002 Swedish women and men who were cancer-free and who completed a 96-item food-frequency questionnaire in 1997. Incident cases of bladder cancer were identified in the Swedish cancer registries.

RESULTS

During a mean follow-up of 9.4 y, 485 participants (76 women and 409 men) were diagnosed with bladder cancer. Total dairy intake was not significantly associated with risk of bladder cancer [> or =7.0 servings/d compared with < 3.5 servings/d: multivariate rate ratio (RR) = 0.87; 95% CI: 0.66, 1.15; P for trend = 0.33]. However, a statistically significant inverse association was observed for the intake of cultured milk (sour milk and yogurt). The multivariate RRs for the highest category of cultured milk intake (> or =2 servings/d) compared with the lowest category (0 serving/d) were 0.62 (95% CI: 0.46, 0.85; P for trend = 0.006) in women and men combined, 0.55 (95% CI: 0.25, 1.22; P for trend = 0.06) in women, and 0.64 (95% CI: 0.46, 0.89; P for trend = 0.03) in men. The intake of milk or cheese was not associated with bladder cancer risk.

CONCLUSION

These findings suggest that a high intake of cultured milk may lower the risk of developing bladder cancer.

The green tea compound, (-)-epigallocatechin-3-gallate downregulates N-cadherin and suppresses migration of bladder carcinoma cells

Green tea has been reported as potential dietary protection against numerous cancers and has been shown to have activity in bladder tumor inhibition in different animal models. The goal of this study was to examine the effects of (-)-epigallocatechin gallate (EGCG-the major phytochemical in green tea) on growth inhibition and behavior of human bladder carcinoma cells and to identify the altered signaling pathway(s) underlying the response to EGCG exposure. EGCG inhibited the in vitro growth of invasive bladder carcinoma cells with an IC(50) range of 70-87 microM. At a concentration of 20 microM, EGCG decreased the migratory potential of bladder carcinoma cells with concomitant activation of p42/44 MAPK and STAT3 and inactivation of Akt. Using biochemical inhibitors of MAPK/ERK, and siRNA to knockdown STAT3 and Akt, inhibition of migration was recorded associated with Akt but not MAPK/ERK or STAT3 signaling in bladder cells. In addition, EGCG downregulated N-cadherin in a dose-dependent manner where reduction in N-cadherin expression paralleled declining migratory potential. Continuous feeding of EGCG to mice prior to and during the establishment of bladder carcinoma xenografts in vivo revealed >50% reduction in mean final tumor volume (P </= 0.05) with no detectable toxicity. EGCG inhibited bladder carcinoma cell growth and suppressed the in vitro migration capacity of cells via downregulation of N-cadherin and inactivation of Akt signaling. Continuous administration of EGCG to mice revealed significant inhibition of tumor growth in vivo indicating a possible preventative role for green tea in bladder cancer.

Reading the tea leaves: anticarcinogenic properties of (-)-epigallocatechin-3-gallate

Green tea is an extremely popular beverage worldwide. Derivatives of green tea, particularly (-)-epigallocatechin-3-gallate (EGCG), have been proposed to have anticarcinogenic properties based on preclinical, observational, and clinical trial data. To summarize, clarify, and extend current knowledge, we conducted a comprehensive search of the PubMed database and other secondary data sources, as appropriate, regarding the chemopreventive potential of EGCG. Apparently, EGCG functions as an antioxidant, preventing oxidative damage in healthy cells, but also as an antiangiogenic agent, preventing tumors from developing a blood supply needed to grow larger. Furthermore, EGCG may stimulate apoptosis in cancerous cells by negatively regulating the cell cycle to prevent continued division. Finally, EGCG exhibits antibacterial activity, which may be implicated in the prevention of gastric cancer. Although in vitro research of the anticarcinogenic properties of EGCG seems promising, many diverse and unknown factors may influence its in vivo activity in animal and human models. Some epidemiological studies suggest that green tea compounds could protect against cancer, but existing data are inconsistent, and limitations in study design hinder full interpretation and generalizability of the published observational findings. Several clinical trials with green tea derivatives are ongoing, and further research should help to clarify the clinical potential of EGCG for chemoprevention and/or chemotherapy applications.

Non-alcoholic beverages and risk of bladder cancer in Uruguay

BACKGROUND

Bladder cancer is the fourth most frequent malignancy among Uruguayan men. A previous study from Uruguay suggested a high risk of bladder cancer associated with maté drinking. We conducted an additional case-control study in order to further explore the role of non-alcoholic beverages in bladder carcinogenesis.

METHODS

In the time period 1996-2000, 255 incident cases with transitional cell carcinoma of the bladder and 501 patients treated in the same hospitals and in the same time period were frequency matched on age, sex, and residence. Both cases and controls were face-to-face interviewed on occupation, tobacco smoking, alcohol drinking and intake of maté, coffee, tea, and soft drinks. Statistical analysis was carried out by unconditional multiple logistic regression.

RESULTS

Ever maté drinking was positively associated with bladder cancer (odds ratio [OR] 2.2, 95% confidence interval [CI] 1.2-3.9) and the risk increased for increasing duration and amount of maté drinking. Both coffee and tea were strongly associated with bladder cancer risk (OR for coffee drinking 1.6, 95% CI 1.2-2.3; OR for tea drinking 2.3, 95% CI 1.5-3.4). These results were confirmed in a separate analysis of never-smokers.

CONCLUSION

Our results suggest that drinking of maté, coffee and tea may be risk factors for bladder carcinoma in Uruguay.

Urinary bladder cancer risk factors in men: a Spanish case–control study

The rising incidence of urinary bladder cancer is alarming and potential relationships with different risk factors have been postulated. The purpose of this study was to examine the possible relationship between different environmental risk factors and urinary bladder cancer. All men with urinary bladder cancer who were admitted to the Department of Urology of Reina Sofia University Hospital of Cordoba, Spain over 1 year were included in our study. Men were administered an interview questionnaire, which included data on history of known urinary bladder cancer risk factors. Comparisons between men with urinary bladder cancer (cases) and those with nonmalignant urological disease (controls) were made. The study included 74 cases and 89 controls. The variables associated with malignant lesions on univariate analysis were age, smoking and drinking alcohol. Meanwhile, fish, poultry and beef consumption were proved to be protective factors. The risk factors identified by the logistic regression analysis were age, smoking and fluid intake. The independent protective factors on the multivariate analysis were fish and poultry consumptions. Smoking was found to be the principal independent risk factors for urinary bladder cancer. Our results call for further investigation of urinary bladder cancer risk factors; future studies should preferably be performed on large prospective cohorts, to increase their validity.

Chemoprevention for Bladder Cancer

PURPOSE

Bladder cancer is the most expensive cancer to treat and follow in the United States due to often extended courses of treatment coupled with the necessity for frequent surveillance examinations. Because direct exposure to carcinogens is implicated in bladder cancer development and many potentially protective compounds are concentrated in urine, bladder cancer is a logical target for chemoprevention.

MATERIALS AND METHODS

We performed a MEDLINE search of the English language literature to identify reports of chemoprevention of bladder cancer. Study outcomes were evaluated and mechanisms of action were identified when possible. In cases of multiple reports of the same compound critical comparisons were performed.

RESULTS

For most putative chemopreventive agents against bladder cancer the results of different studies are conflicting. Megadose vitamins, certain vitamin A analogues and pyridoxines have been associated with promising findings. For vitamins C and E and selenium, studies showing benefit are balanced by studies showing no benefit. Other compounds, such as soy, green tea and isothiocyanates, have been suggested by some studies to be protective and by others to be tumor promoting.

CONCLUSIONS

For most bladder cancer chemopreventive agents studied to date results regarding efficacy vary, precluding the possibility of universal support by health care providers for this specific role. Megadose multivitamin supplements have demonstrated the ability to prevent bladder cancer recurrences in a single smaller study. Some analogues of vitamins A, B6, C and E have been shown to be beneficial in other disease processes, suggesting that these compounds may be advocated with the caveat that they do not have a specific protective role in bladder cancer. Data from randomized, prospective trials show a benefit in bladder cancer only after eliminating early or initial recurrences, suggesting the need for long-term administration of a chosen agent. Additional prospective trials with long-term followup, likely involving multiple institutions, are required before definitive recommendations can be made about chemoprevention for bladder cancer. In 2006 no oral agent can be recommended and to our knowledge the best chemopreventive strategy remains to be determined.

Electrochemical studies of (−)-epigallocatechin gallate and its interaction with DNA

In this paper, an electrochemical investigation of (-)-epigallocatechin gallate (EGCG) and its interaction with DNA is presented. Via an electrochemical approach assisted by ultraviolet-visible (UV-Vis) spectroscopy, we propose that EGCG can intercalate into DNA strands forming a nonelectroactive complex, which results in the decrease of the anodic peak current of EGCG. Meanwhile, an electrochemical study with the DNA-Cu(II)-EGCG system shows that damage to DNA can be recognized electrochemically via the increase in the anodic peak current resulting from the oxidation of guanine and adenine bases. The damage can also be recognized spectrophotometrically via an increase in the 260 nm absorption band. In addition, it was found that EGCG is able to discriminate dsDNA from ssDNA, making a potential electrochemical indicator for the detection of DNA hybridization events. A rapid and convenient method of detecting EGCG was also developed in this work.

Black tea--helpful or harmful? A review of the evidence

OBJECTIVE

To consider whether consumption of black tea has a positive or negative impact on health.

DESIGN

Databases were searched for relevant epidemiological and clinical studies published between 1990 and 2004.

RESULTS

Clear evidence was found for coronary heart disease (CHD), where an intake of > or = 3 cups per day related to risk reduction. The mechanism could involve the antioxidant action of tea polyphenols. While experimental models have suggested that flavonoids attenuated cancer risk, epidemiological studies failed to demonstrate a clear effect for tea, although there is moderate evidence for a slightly positive or no effect of black tea consumption on colorectal cancer. Studies on cancer were limited by sample sizes and insufficient control of confounders. There is moderate evidence suggestive of a positive effect of black tea consumption on bone mineral density although studies were few. There is little evidence to support the effect of tea on dental plaque inhibition but evidence to support the contribution of tea to fluoride intakes and thus theoretical protection against caries. There was no credible evidence that black tea (in amounts typically consumed) was harmful. Normal hydration was consistent with tea consumption when the caffeine content was < 250 mg per cup. A moderate caffeine intake from tea appeared to improve mental performance, although sample sizes were small. There was no evidence that iron status could be harmed by tea drinking unless populations were already at risk from anaemia.

CONCLUSIONS

There was sufficient evidence to show risk reduction for CHD at intakes of > or = 3 cups per day and for improved antioxidant status at intakes of one to six cups per day. A maximum intake of eight cups per day would minimise any risk relating to excess caffeine consumption. Black tea generally had a positive effect on health.

Soy phytochemicals prevent orthotopic growth and metastasis of bladder cancer in mice by alterations of cancer cell proliferation and apoptosis and tumor angiogenesis

A role of dietary bioactive components in bladder cancer prevention is biologically plausible because most substances or metabolites are excreted through the urinary tract and are consequently in direct contact with the mucosa of the bladder. We first determined antigrowth activity of genistein against poorly differentiated 253J B-V human bladder cancer cells in vitro. Genistein inhibited the cell growth in a time- and dose-dependent manner via G(2)-M arrest, down-regulation of nuclear factor kappaB (NF-kappaB), and induction of apoptosis. We also evaluated both genistin, which is a natural form of genistein, and the isoflavone-rich soy phytochemical concentrate (SPC) on the growth and metastasis of 253J B-V tumors in an orthotopic tumor model. Mice treated with genistin and SPC had reduced final tumor weights by 56% (P < 0.05) and 52% (P < 0.05), respectively, associated with induction of tumor cell apoptosis and inhibition of tumor angiogenesis in vivo. In addition, SPC treatment, but not genistin treatment, significantly inhibited lung metastases by 95% (P < 0.01) associated with significant down-regulation of NF-kappaB expression in tumor tissues and reduction of circulating insulin-like growth factor-I levels, suggesting that SPC may contain other bioactive ingredients that have antimetastatic activity. The results from our studies suggest that further clinical investigation should be warranted to apply soy phytochemicals, such as SPC, as a potent prevention regimen for bladder cancer progression. This orthotopic human bladder tumor model also provides a clinically relevant experimental tool for assessing potential preventive activity of other dietary components against bladder tumor growth and metastasis.

Evaluation for safety of antioxidant chemopreventive agents

Antioxidants are considered as the most promising chemopreventive agents against various human cancers. However, some antioxidants play paradoxical roles, acting as "double-edged sword." A primary property of effective and acceptable chemopreventive agents should be freedom from toxic effects in healthy population. Miscarriage of the intervention by beta-carotene made us realize the necessity for evaluation of safety before recommending use of antioxidant supplements for chemoprevention. We have evaluated the safety of antioxidants on the basis of reactivity with DNA. Our results revealed that phytic acid, luteolin, and retinoic acid did not cause DNA damage under the experimental condition. Furthermore, phytic acid inhibited the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine, an indicator of oxidative DNA damage, in cultured cells treated with a H(2)O(2)-generating system. Thus, it is expected that these chemopreventive agents can safely protect humans against cancer. On the other hand, some chemopreventive agents with prooxidant properties (alpha-tocopherol, quercetin, catechins, isothiocyanates, N-acetylcysteine) caused DNA damage via generation of reactive oxygen species in the presence of metal ions and endogenous reductants under some circumstances. Furthermore, other chemopreventive agents (beta-carotene, genistein, daidzein, propyl gallate, curcumin) exerted prooxidant properties after metabolic activation. Therefore, further studies on safety should be required when antioxidants are used for cancer prevention.

Mechanisms of inhibition of tumor angiogenesis and vascular tumor growth by epigallocatechin-3-gallate

PURPOSE

Green tea consumption has been linked to a reduced occurrence of some tumor types. Current data indicate that the principal mediator of this chemopreventive effect is epigallocatechin-3-gallate (EGCG), the most abundant polyphenol found in dried tea leaves. Here, we examined the effects of this compound on the two key cell populations typically involved in tumor growth: tumor cells and endothelial cells.

EXPERIMENTAL DESIGN

The effects of green tea and EGCG were tested in a highly vascular Kaposi's sarcoma (KS) tumor model and on endothelial cells in a panel of in vivo and in vitro assays.

RESULTS

EGCG inhibited KS-IMM cell growth and endothelial cell growth, chemotaxis, and invasion over a range of doses; high concentrations also induced tumor cell apoptosis. EGCG inhibited the metalloprotease-mediated gelatinolytic activity produced by endothelial cell supernatants and the formation of new capillary-like structures in vitro. Green tea or purified EGCG when administered to mice in the drinking water inhibited angiogenesis in vivo in the Matrigel sponge model and restrained KS tumor growth. Histological analysis of the tumors were consistent with an anti-angiogenic activity of EGCG and green tea.

CONCLUSIONS

These data suggest that the green tea gallate or its derivatives may find use in the prevention and treatment of vascular tumors in a chemoprevention or adjuvant setting.

Mediation of the in vitro cytotoxicity of green and black tea polyphenols by cobalt chloride

The effects of Co2+ (as CoCl2) on the cytotoxicity of green tea polyphenol (GTP) and black tea polyphenol (BTP) extracts towards proliferation of immortalized human gingival epithelial-like S-G cells were studied. The 24 h potencies of GTP and BTP extracts, as determined with the neutral red (NR) cell viability assay, were greatly reduced in the presence of 250, but not of 50, microM Co2+. The cytotoxicities of the GTP and BTP extracts were due, in part, to their generation of hydrogen peroxide (H2O2) in the cell culture medium (DMEM). Progressively increasing the concentration of Co2+ in the tea polyphenol-amended cell culture medium resulted in a lowering of the level of H2O2. The cytotoxicity of freshly added H2O2 to S-G cells was abolished in the presence of 250 microM Co2+ and the level of freshly added H2O2 to cell culture medium was progressively lowered as the concentration of Co2+ was increased. Apparently, under the conditions of these studies, the decreases in the cytotoxicity of GTP and BTP extracts in the presence of CoCl2 were due to the rapid catalytic decomposition by Co2+ of the H2O2 generated in the tea polyphenol-amended cell culture medium.

Botanical medicine and cancer: a review of the safety and efficacy

It is currently estimated that > 50% of all patients diagnosed with cancer explore complementary and alternative medicine - especially herbal medicine. We conducted a comprehensive review to assess the safety and efficacy of herbal medicines commonly used by patients in an attempt to: prevent cancer; treat cancer; and treat adverse effects associated with conventional cancer treatments. Current evidence suggests that Asian ginseng, garlic, green tea, tomatoes and soy intake as part of the diet may be useful in preventing various cancers; additional research is needed in order to determine the efficacy of essiac, evening primrose oil, mistletoe, reishi, shiitake and turmeric as cancer treatments; and ginger may be effective in treating chemotherapy-induced nausea and vomiting.

In vitro Cytotoxicity of Epigallocatechin Gallate and Tea Extracts to Cancerous and Normal Cells from the Human Oral Cavity

This study compared the in vitro responses of malignant and normal cells from the human oral cavity to tea extracts and to its main polyphenolic component, (-)-epigallocatechin gallate (EGCG). The antiproliferative effects of tea polyphenolic extracts and EGCG were more pronounced towards immortalized, tumourigenic (CAL27, HSC-2, and HSG(1)) and non-tumourigenic (S-G) cells than towards normal (GN56 and HGF-1) fibroblasts and green tea was more toxic than black tea. As the addition of tea extract or EGCG to cell culture medium led to the formation of hydrogen peroxide (H(2)O(2)), the research then focused on EGCG as an inducer of oxidative stress, using CAL27, the cancerous cells most sensitive to EGCG, HSG(1), the cancerous cells least sensitive to EGCG, and GN56 cells. The toxicity of EGCG was decreased in the presence of catalase, an enzyme that degrades H(2)O(2), or of deferoxamine, a chelator of Fe(3+). Conversely, pretreatment of the cells with the glutathione depleters, 1-chloro-2,4-dinitrobenzene and 1,3-bis(2-chloroethyl)-N-nitrosourea, potentiated the toxicity of EGCG. A 4-hr exposure to EGCG lessened the intracellular level of reduced glutathione in the CAL27 and HSG(1) cells, but not in the GN56 fibroblasts. Whereas EGCG itself did not induce lipid peroxidation, Fe(2+)-induced lipid peroxidation was potentiated by EGCG. A 72-hr exposure to cytotoxic concentrations of EGCG induced significant cytoplasmic vacuolization in all cell types. The results presented herein are consistent with EGCG acting as a prooxidant, with the cancerous cells more sensitive to oxidative stress than the normal cells.

Effect of green tea extract on the induction of ornithine decarboxylase and the activation of extracellular signal-regulated kinase in bladder carcinoma ECV304 cells

According to several studies, green tea and individual catechins can inhibit the induction of ornithine decarboxylase (ODC), the key enzyme in the biosynthesis of polyamines. It has been suggested that the inhibition of ODC induction may offer an explanation to the anticancer and chemopreventive activities of green tea. In the present study, however, treatment of bladder carcinoma ECV304 cells with green tea extract (GTE) was not able to reduce the induction of ODC by fetal calf serum. Actually, in the absence of serum, GTE provoked a dose-dependent and remarkable induction of ODC activity. The induction of ODC, which could be elicited also by (-)-epigallocatechin 3-gallate, a major green tea component, required an early activation of extracellular signal-regulated kinase 1 and 2 (ERK), and both events appeared to be dependent on an alteration of the status of cellular thiol groups. Pretreatment with specific ERK or ODC inhibitors was able to prevent a late caspase activation but hardly affected the loss of cell viability provoked by GTE. In conclusion, to our knowledge, this is the first study showing that GTE can promote ODC induction in a tumor cell line.

Foods and beverages in relation to urothelial cancer: case-control study in Japan

BACKGROUND

The roles of several foods and beverages in the development of bladder cancer remain unclear.

METHODS

We undertook a hospital-based case-control study at Aichi Cancer Center Hospital, Japan. Subjects included 124 men and women (bladder cancer cases) with newly diagnosed cancers of the renal pelvis (n = 5), ureter (n = 6) or bladder (n = 113) and 620 age- and sex-matched, cancer-free outpatients (controls) presenting at the hospital in the period from 1994 to 2000. Smoking-adjusted odds ratios (OR) were estimated to assess the strength of associations between self-reported intake of foods or drinks and bladder cancer risk, using conditional logistic models.

RESULTS

We found a decreased risk in relation to frequent intake of green-yellow vegetables; the OR for the highest intake score compared with the lowest was 0.54 (95% confidence interval [CI] 0.29-0.99). The OR for carrot intake of >/=5 times/week compared with </=1-3 times/month was 0.41 (95% CI 0.16-1.01) and a decreasing risk with increasing consumption of green vegetables was also detected (P for trend = 0.063). Inverse associations between black tea, eggs and meat and risk were also suggested, whereas moderate drinkers of green tea (5-9 cups/day) showed an elevated risk. Coffee and milk consumption did not appear to exert any influence.

CONCLUSIONS

Those with an increased risk of bladder cancer, such as smokers, may benefit from increasing their consumption of green-yellow vegetables.