Green tea consumption enhances survival of epithelial ovarian cancer

Association of protein intake with recurrence and survival following primary treatment of ovarian cancer

BACKGROUND

Malnutrition is common during treatment for ovarian cancer and one in three report multiple symptoms affecting food intake after primary treatment. Little is known about diet post-treatment in relation to ovarian cancer survival, however, general recommendations for cancer survivors are to maintain a higher level of protein intake to support recovery and minimize nutritional deficits.

OBJECTIVE

To investigate whether intake of protein and protein food sources following primary treatment for ovarian cancer is associated with recurrence and survival.

DESIGN

Intake levels of protein and protein food groups were calculated from dietary data collected about 12 months post-diagnosis using a validated food frequency questionnaire in an Australian cohort of females with invasive epithelial ovarian cancer. Disease recurrence and survival status were abstracted from medical records (median 4.9 years follow-up). Cox proportional hazards regression was used to calculate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for protein intake and progression-free and overall survival.

RESULTS

Among 591 females who were progression-free at 12-months follow-up, 329 (56%) subsequently experienced cancer recurrence and 231 (39%) died. A higher level of protein intake was associated with better progression-free survival (>1-1.5 vs. ≤1 grams per kilogram body weight (g/kg): HR_adjusted=0.69, 95% CI 0.48, 1.00; >1.5 vs. ≤1g/kg: HR_adjusted=0.61, 95% CI 0.41, 0.90; >20% vs. ≤20% total energy intake from protein: HR_adjusted=0.77, 95% CI 0.61, 0.96). There was no evidence for better progression-free survival with any particular protein food sources. There was a suggestion of better overall survival among those with higher total intakes of animal-based protein foods, particularly dairy products (HR=0.71, 95% CI 0.51, 0.99 for highest vs. lowest tertiles of total dairy intake).

CONCLUSIONS

After primary treatment for ovarian cancer, a higher level of protein intake may benefit progression-free survival. Ovarian cancer survivors should avoid dietary practices that limit intake of protein-rich foods.

Green Tea in Reproductive Cancers: Could Treatment Be as Simple?

Green tea originates from the tea plant Camellia sinensis and is one of the most widely consumed beverages worldwide. Green tea polyphenols, commonly known as catechins, are the major bioactive ingredients and account for green tea's unique health benefits. Epigallocatechin-3-gallate (EGCG), is the most potent catechin derivative and has been widely studied for its pro- and anti-oxidative effects. This review summarizes the chemical and chemopreventive properties of green tea in the context of female reproductive cancers. A comprehensive search of PubMed and Google Scholar up to December 2022 was conducted. All original and review articles related to green tea or EGCG, and gynecological cancers published in English were included. The findings of several in vitro, in vivo, and epidemiological studies examining the effect of green tea on reproductive cancers, including ovarian, cervical, endometrial, and vulvar cancers, are presented. Studies have shown that this compound targets specific receptors and intracellular signaling pathways involved in cancer pathogenesis. The potential benefits of using green tea in the treatment of reproductive cancers, alone or in conjunction with chemotherapeutic agents, are examined, shedding light on new therapeutic strategies for the management of female reproductive cancers.

Tea Polyphenols and Their Preventive Measures against Cancer: Current Trends and Directions

Cancer is exerting an immense strain on the population and health systems all over the world. Green tea because of its higher simple catechin content (up to 30% on dry weight basis) is greatly popular as an anti-cancer agent which is found to reduce the risks of cancer as well as a range of other diseases. In addition, several in vitro and in vivo studies have shown that green tea possesses copious health benefits like anti-diabetic, anti-obese, anti-inflammatory, neuro-protective, cardio-protective, etc. This review highlights the anti-carcinogenic effects of green tea catechins integrating the recent information to gain a clear concept. Special emphasis was given to the effectiveness of green tea polyphenols (GTP) in the prevention of cancer. Overall, green tea has been found to be effective to reduce the risks of breast cancer, ovarian cancer, liver cancer, colorectal cancer, skin cancer, prostate cancer, oral cancer, etc. However, sufficient information was not found to support that green tea consumption reduces the risk of lung cancer, esophageal cancer, or stomach cancer. The exciting data integrated into this article will increase interest in future researchers to garner more fruitful information on the relevant topics.

Association between Energy Balance-Related Factors and Clinical Outcomes in Patients with Ovarian Cancer: A Systematic Review and Meta-Analysis

Background: This systematic review and meta-analysis synthesized evidence in patients with ovarian cancer at diagnosis and/or during first-line treatment on; (i) the association of body weight, body composition, diet, exercise, sedentary behavior, or physical fitness with clinical outcomes; and (ii) the effect of exercise and/or dietary interventions. Methods: Risk of bias assessments and best-evidence syntheses were completed. Meta-analyses were performed when ≥3 papers presented point estimates and variability measures of associations or effects. Results: Body mass index (BMI) at diagnosis was not significantly associated with survival. Although the following trends were not supported by the best-evidence syntheses, the meta-analyses revealed that a higher BMI was associated with a higher risk of post-surgical complications (n = 5, HR: 1.63, 95% CI: 1.06−2.51, p = 0.030), a higher muscle mass was associated with a better progression-free survival (n = 3, HR: 1.41, 95% CI: 1.04−1.91, p = 0.030) and a higher muscle density was associated with a better overall survival (n = 3, HR: 2.12, 95% CI: 1.62−2.79, p < 0.001). Muscle measures were not significantly associated with surgical or chemotherapy-related outcomes. Conclusions: The prognostic value of baseline BMI for clinical outcomes is limited, but muscle mass and density may have more prognostic potential. High-quality studies with comprehensive reporting of results are required to improve our understanding of the prognostic value of body composition measures for clinical outcomes. Systematic review registration number: PROSPERO identifier CRD42020163058.

Green Tea Epigallocatechin-3-Gallate Regulates Autophagy in Male and Female Reproductive Cancer

With a rich abundance of natural polyphenols, green tea has become one of the most popular and healthiest nonalcoholic beverages being consumed worldwide. Epigallocatechin-3-gallate (EGCG) is the predominant catechin found in green tea, which has been shown to promote numerous health benefits, including metabolic regulation, antioxidant, anti-inflammatory, and anticancer. Clinical studies have also shown the inhibitory effects of EGCG on cancers of the male and female reproductive system, including ovarian, cervical, endometrial, breast, testicular, and prostate cancers. Autophagy is a natural, self-degradation process that serves important functions in both tumor suppression and tumor cell survival. Naturally derived products have the potential to be an effective and safe alternative in balancing autophagy and maintaining homeostasis during tumor development. Although EGCG has been shown to play a critical role in the suppression of multiple cancers, its role as autophagy modulator in cancers of the male and female reproductive system remains to be fully discussed. Herein, we aim to provide an overview of the current knowledge of EGCG in targeting autophagy and its related signaling mechanism in reproductive cancers. Effects of EGCG on regulating autophagy toward reproductive cancers as a single therapy or cotreatment with other chemotherapies will be reviewed and compared. Additionally, the underlying mechanisms and crosstalk of EGCG between autophagy and other cellular processes, such as reactive oxidative stress, ER stress, angiogenesis, and apoptosis, will be summarized. The present review will help to shed light on the significance of green tea as a potential therapeutic treatment for reproductive cancers through regulating autophagy.

Association between dietary intake and risk of ovarian cancer: a systematic review and meta-analysis

PURPOSE

It is unclear how dietary intake influences the ovarian cancer. The present paper sets out to systematically review and meta-analyze research on dietary intake to identify cases having high- or low-risk ovarian cancer.

METHODS

Scopus, PubMed, and Wiley Online Libraries were searched up to the date November 24, 2019. Two reviewers were requested to independently extract study characteristics and to assess the bias and applicability risks with reference to the study inclusion criteria. Meta-analyses were performed to specify the relationship between dietary intake and the risk of ovarian cancer identifying 97 cohort studies.

RESULTS

No significant association was found between dietary intake and risk of ovarian cancer. The results of subgroup analyses indicated that green leafy vegetables (RR = 0.91, 95%, 0.85-0.98), allium vegetables (RR = 0.79, 95% CI 0.64-0.96), fiber (RR = 0.89, 95% CI 0.81-0.98), flavonoids (RR = 0.83, 95% CI 0.78-0.89) and green tea (RR = 0.61, 95% CI 0.49-0.76) intake could significantly reduce ovarian cancer risk. Total fat (RR = 1.10, 95% CI 1.02-1.18), saturated fat (RR = 1.11, 95% CI 1.01-1.22), saturated fatty acid (RR = 1.19, 95% CI 1.04-1.36), cholesterol (RR = 1.13, 95% CI 1.04-1.22) and retinol (RR = 1.14, 95% CI 1.00-1.30) intake could significantly increase ovarian cancer risk. In addition, acrylamide, nitrate, water disinfectants and polychlorinated biphenyls were significantly associated with an increased risk of ovarian cancer.

CONCLUSION

These results could support recommendations to green leafy vegetables, allium vegetables, fiber, flavonoids and green tea intake for ovarian cancer prevention.

The use of complementary and alternative medicine (CAM) among cancer patients at a tertiary hospital in Malaysia

PURPOSE

Complementary and alternative medicine (CAM) use among cancer patients is increasing over the years. Some types of CAM may interact with conventional cancer therapy or may cause serious adverse effects. This study was designed to determine the prevalence of CAM use among cancer patients during cancer therapy and to identify CAM users' characteristics, perception, reasoning, expectation and disclosure of CAM use.

METHOD

This cross-sectional study was conducted between July 2017 to October 2017, on 121 cancer patients in oncology and hematology clinics and daycare of a tertiary hospital in Kuala Lumpur, Malaysia. Study data was collected using a self-administered questionnaire.

RESULTS

The prevalence of CAM use among cancer patients was found to be 61.2 %. Multivariate logistic regression analysis showed that CAM use was associated with change in outlook on life after development of cancer. The most frequently used types of CAM were vitamins and Islamic medical practices. Majority of patients were guided by family and friends' suggestions towards using CAM. Most patients expected CAM to cure their disease. The percentage of patients who disclosed CAM use to the doctors was slightly higher than those who did not disclose CAM use.

CONCLUSION

The use of CAM was found to be remarkably high. Rate of non-disclosure of CAM use was high indicating the need for enhancement of doctor- patient relationship for effective patient's care. Future research is needed with large sample of patients to provide better representation of the population and to help understand patients' beliefs and perception more.

Green tea (Camellia sinensis) for the prevention of cancer

BACKGROUND

This review is an update of a previously published review in the Cochrane Database of Systematic Reviews (2009, Issue 3).Tea is one of the most commonly consumed beverages worldwide. Teas from the plant Camellia sinensis can be grouped into green, black and oolong tea, and drinking habits vary cross-culturally. C sinensis contains polyphenols, one subgroup being catechins. Catechins are powerful antioxidants, and laboratory studies have suggested that these compounds may inhibit cancer cell proliferation. Some experimental and nonexperimental epidemiological studies have suggested that green tea may have cancer-preventative effects.

OBJECTIVES

To assess possible associations between green tea consumption and the risk of cancer incidence and mortality as primary outcomes, and safety data and quality of life as secondary outcomes.

SEARCH METHODS

We searched eligible studies up to January 2019 in CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and reference lists of previous reviews and included studies.

SELECTION CRITERIA

We included all epidemiological studies, experimental (i.e. randomised controlled trials (RCTs)) and nonexperimental (non-randomised studies, i.e. observational studies with both cohort and case-control design) that investigated the association of green tea consumption with cancer risk or quality of life, or both.

DATA COLLECTION AND ANALYSIS

Two or more review authors independently applied the study criteria, extracted data and assessed methodological quality of studies. We summarised the results according to diagnosis of cancer type.

MAIN RESULTS

In this review update, we included in total 142 completed studies (11 experimental and 131 nonexperimental) and two ongoing studies. This is an additional 10 experimental and 85 nonexperimental studies from those included in the previous version of the review. Eleven experimental studies allocated a total of 1795 participants to either green tea extract or placebo, all demonstrating an overall high methodological quality based on 'Risk of bias' assessment. For incident prostate cancer, the summary risk ratio (RR) in the green tea-supplemented participants was 0.50 (95% confidence interval (CI) 0.18 to 1.36), based on three studies and involving 201 participants (low-certainty evidence). The summary RR for gynaecological cancer was 1.50 (95% CI 0.41 to 5.48; 2 studies, 1157 participants; low-certainty evidence). No evidence of effect of non-melanoma skin cancer emerged (summary RR 1.00, 95% CI 0.06 to 15.92; 1 study, 1075 participants; low-certainty evidence). In addition, adverse effects of green tea extract intake were reported, including gastrointestinal disorders, elevation of liver enzymes, and, more rarely, insomnia, raised blood pressure and skin/subcutaneous reactions. Consumption of green tea extracts induced a slight improvement in quality of life, compared with placebo, based on three experimental studies. In nonexperimental studies, we included over 1,100,000 participants from 46 cohort studies and 85 case-control studies, which were on average of intermediate to high methodological quality based on Newcastle-Ottawa Scale 'Risk of bias' assessment. When comparing the highest intake of green tea with the lowest, we found a lower overall cancer incidence (summary RR 0.83, 95% CI 0.65 to 1.07), based on three studies, involving 52,479 participants (low-certainty evidence). Conversely, we found no association between green tea consumption and cancer-related mortality (summary RR 0.99, 95% CI 0.91 to 1.07), based on eight studies and 504,366 participants (low-certainty evidence). For most of the site-specific cancers we observed a decreased RR in the highest category of green tea consumption compared with the lowest one. After stratifying the analysis according to study design, we found strongly conflicting results for some cancer sites: oesophageal, prostate and urinary tract cancer, and leukaemia showed an increased RR in cohort studies and a decreased RR or no difference in case-control studies.

AUTHORS' CONCLUSIONS

Overall, findings from experimental and nonexperimental epidemiological studies yielded inconsistent results, thus providing limited evidence for the beneficial effect of green tea consumption on the overall risk of cancer or on specific cancer sites. Some evidence of a beneficial effect of green tea at some cancer sites emerged from the RCTs and from case-control studies, but their methodological limitations, such as the low number and size of the studies, and the inconsistencies with the results of cohort studies, limit the interpretability of the RR estimates. The studies also indicated the occurrence of several side effects associated with high intakes of green tea. In addition, the majority of included studies were carried out in Asian populations characterised by a high intake of green tea, thus limiting the generalisability of the findings to other populations. Well conducted and adequately powered RCTs would be needed to draw conclusions on the possible beneficial effects of green tea consumption on cancer risk.

Tea Consumption and Health Outcomes: Umbrella Review of Meta-Analyses of Observational Studies in Humans

SCOPE

The aim of this article is to conduct an umbrella review to study the strength and validity of associations between tea consumption and diverse health outcomes.

METHODS AND RESULTS

Meta-analyses of observational studies examining associations between tea consumption and health outcomes in all human populations and settings are screened. The umbrella review identifies 96 meta-analyses with 40 unique health outcomes. Tea consumption shows greater benefits than harm to health in this review. Dose-response analyses of tea consumption indicates reduced risks of total mortality, cardiac death, coronary artery disease, stroke, and type 2 diabetes mellitus with increment of two to three cups per day. Beneficial associations are also found for several cancers, skeletal, cognitive, and maternal outcomes. Harmful associations are found for esophageal and gastric cancer when the temperature of intake is more than 55-60 °C.

CONCLUSION

Tea consumption, except for very hot tea, seems generally safe at usual levels of intake, with summary estimates indicating the largest reduction for diverse health outcomes at two to three cups per day. Generally, tea consumption seems more beneficial than harmful in this umbrella review. Randomized controlled trials are further needed to understand whether the observed associations are causal.

Green tea supplementation upregulates uncoupling protein 3 expression in severe obese women adipose tissue but does not promote weight loss

This study aims (i) to verify expression of the UCPs, PLIN1, PPARG2, and ADRB3 genes in the abdominal subcutaneous adipose tissue of obese women at baseline and after 8 weeks of supplementation with decaffeinated green tea extract, and (ii) to associate findings with clinical parameters. This is a longitudinal study during which 11 women with obesity grade III were submitted to supplementation with 450 mg of (-)-epigallocatechin gallate (EGCG) (intervention group); the control group consisted of 10 eutrophic women. Anthropometric parameters [weight, height, and body mass index (BMI)], resting metabolic rate (RMR, measured by indirect calorimetry), and gene expression (measured by real-time PCR, RT-qPCR) were determined before and after supplementation. After 8 weeks, clinical parameters and UCP1, PLIN1, PPARG2, and ADRB3 expression remained unaltered in the intervention group (p > .05). Genetic analysis also showed that the UCP3 gene was upregulated (p = .026), but its upregulation did not promote weight loss.

Pre-diagnosis diet and survival after a diagnosis of ovarian cancer

Background:

The relationship between diet and survival after ovarian cancer diagnosis is unclear as a result of a limited number of studies and inconsistent findings.

Methods:

We examined the association between pre-diagnostic diet and overall survival in a population-based cohort (n=811) of Australian women diagnosed with invasive epithelial ovarian cancer between 2002 and 2005. Diet was measured by validated food frequency questionnaire. Deaths were ascertained up to 31 August 2014 via medical record review and Australian National Death Index linkage. We conducted Cox proportional hazards regression analysis, controlling for diagnosis age, tumour stage, grade and subtype, residual disease, smoking status, body mass index, physical activity, marital status, and energy intake.

Results:

We observed improved survival with highest compared with lowest quartile of fibre intake (hazard ratio (HR)=0.69, 95% CI: 0.53–0.90, P-trend=0.002). There was a suggestion of better survival for women with highest compared with lowest intake category of green leafy vegetables (HR=0.79, 95% CI: 0.62–0.99), fish (HR=0.74, 95% CI: 0.57–0.95), poly- to mono-unsaturated fat ratio (HR=0.76, 95% CI: 0.59–0.98), and worse survival with higher glycaemic index (HR=1.28, 95% CI: 1.01–1.65, P-trend=0.03).

Conclusions:

The associations we observed between healthy components of diet pre-diagnosis and ovarian cancer survival raise the possibility that dietary choices after diagnosis may improve survival.

Environmental (nongenetic) factors in gynecological cancers: update and future perspectives

Globally, gynecological cancers comprise three of the seven most common female cancers and are responsible for more than 1,000,000 new cases and 500,000 deaths annually. This review summarizes current knowledge regarding the role of environmental factors in gynecological cancer etiology and survival, focusing on those that are potentially amenable to intervention. Strong associations with use of exogenous hormones are countered by opposing risks of breast cancer, thus current hormonal preparations are not an option for prevention. Weight control would reduce risk of endometrial cancer but this and other lifestyle modifications are unlikely to have a major effect on gynecological cancer mortality rates. There is little information regarding the potential for lifestyle changes to improve outcomes for women with gynecological cancer.

Analysis of the effect of the active compound of green tea (EGCG) on the proliferation of peripheral blood mononuclear cells

Background

Cancer immunotherapy requires proper manipulation of the immune system, lymphocytes in particular, in order to identify and destroy the cancer cells as non-self. In this study we investigated the effect of the flavonoid present in green tea, namely epigallocatechin-3-gallate (EGCG), on the proliferation of, and IFN-γ production by, peripheral blood mononuclear cells (PBMC) from breast cancer patients stimulated with a mitogen, anti-CD3 and the common breast cancer peptides Her-2/neu, and p53.

Methods

Blood samples were collected from 25 patients with breast cancer at the Kuwait Cancer Control Centre (KCCC). The patients were newly diagnosed, and had not undergone any treatment or surgery at the time of sample collection. The control group consisted of 25 healthy women age-matched (±5 years) to the patients. PBMC were isolated from the patients and controls, and were cultured separately with the mitogen PHA, anti-CD3 antibodies, and Her-2/neu and p53 in the presence or absence of standardized doses of EGCG. The degree of proliferation and interferon-γ [IFN-γ) release were then analyzed.

Results

EGCG significantly suppressed the proliferation of PBMC in response to stimulation separately with (i) the mitogen, (ii) anti-CD3, and (iii) the cancer antigen peptides. IFN-γ production was also significantly suppressed by EGCG in vitro.

Conclusions

EGCG appears to have an immunosuppressive effect on the proliferation of PBMC, indicating that EGCG is worth exploring for immunomodulatory effects in autoimmune diseases and tissue transplantation.

Dietary intake and ovarian cancer risk: a systematic review

Ovarian cancer is a leading cause of gynecological cancer death. There is a need to identify modifiable dietary risk factors for this disease. To evaluate the role of diet in ovarian cancer risk, we performed a PRISMA-directed systematic review that included prospective cohort studies with >200 cases (n = 24). Higher risk for ovarian cancer was shown for total, animal, and dairy fat (five of nine studies), as well as total nitrate and possibly total vitamin C. No associations were demonstrated for red meat, fiber, vitamin A, vitamin E, β-carotene, or folate. Vegetables were associated with lower risk in one of three studies; fruit showed no association, although risk estimates were all greater than 1.0. Isoflavones and flavonoids were associated with modestly lower risk in two studies and tea intake was associated with lower risk in one of two studies. This review suggests that no specific dietary factors are consistently associated with ovarian cancer risk. Data by tumor subtypes are limited, but suggest that differential associations by tumor subtype may exist and should be evaluated. Studies of ample sample size, varied exposure, which can better control for dietary measurement error, are needed to fully define dietary recommendations for ovarian cancer prevention.

A two-stage, single-arm, phase II study of EGCG-enriched green tea drink as a maintenance therapy in women with advanced stage ovarian cancer

OBJECTIVES

A two-stage, single-arm, phase II study was conducted to assess the effectiveness and safety of an epigallocatechin gallate (EGCG)-enriched tea drink, the double-brewed green tea (DBGT), as a maintenance treatment in women with advanced stage serous or endometrioid ovarian cancer (clinicaltrials.gov, NCT00721890).

METHODS

Eligible women had FIGO stage III-IV serous or endometrioid ovarian cancer. They had to undergo complete response after debulking surgery followed by 6 to 8 cycles of platinum/taxane chemotherapy at the Centre Hospitalier Universitaire de Québec. They all had to drink the DBGT, 500 mL daily until recurrence or during a follow-up of 18 months. The primary endpoint was the absence of recurrence at 18 months. Statistical analyses were done according to the principle of intention to treat. Using a two-stage design, the first stage consisted of 16 enrolled patients. At the end of the follow-up, if 7 or fewer patients were free of recurrence, the trial stopped. Otherwise, accrual would continue to a total of 46 patients.

RESULTS

During the first stage of the study, only 5 of the 16 women remained free of recurrence 18 months after complete response. Accordingly, the clinical trial was terminated. Women's adherence to DBGT was high (median daily intake during intervention, 98.1%, interquartile range: 89.7-100%), but 6 women discontinued the intervention before the end of their follow-up. No severe toxicity was reported.

CONCLUSIONS

DBGT supplementation does not appear to be a promising maintenance intervention in women with advanced stage ovarian cancer after standard treatment.

What is integrative oncology and can it help my patients?

Integrative oncology lends itself to the comprehensive practice of gynecologic oncology with multiple tools and interventions that can impact on QoL and survival. However, there remains a paucity of well-designed, well-powered randomized control trials on various CAM modalities for gynecologic cancer patients. The reasons for the lack of level 1 evidence include the nascent state of integrative medicine as a science, the limitations on CAM funding, the relative lack of integration of CAM practitioners into the oncology community, and absence of strict regulation of herbs and supplements by the US FDA. The use of CAM as adjunctive therapies will likely continue given the patient-driven trends to date, and given the evidence for at least safety and potentially efficacy, our patients deserve our willingness to use all possible approaches to improving their outcomes. Continued evolution of our ability to specifically measure and describe QoL will further our ability to hone in on domains most important to patients and their survival and allow practitioners to make patient-specific recommendations. Multimodal programs that include physical activity, stress management, and diet have the potential to address demonstrated deficits in PWB and FWB in ovarian cancer patients which suggests a model of collaborative gynecologic oncology care). Integrative oncology represents a holistic approach to patient care whose goal is maximization of patient quantity and quality of life. Patients can achieve this optimal outcome through the synergy of conventional care, integrative modalities, lifestyle modifications, and supportive care. Refer to Table 4 for a listing of integrated medicine Internet resources.

Nutrition and physical activity guidelines for cancer survivors

Cancer survivors are often highly motivated to seek information about food choices, physical activity, and dietary supplements to improve their treatment outcomes, quality of life, and overall survival. To address these concerns, the American Cancer Society (ACS) convened a group of experts in nutrition, physical activity, and cancer survivorship to evaluate the scientific evidence and best clinical practices related to optimal nutrition and physical activity after the diagnosis of cancer. This report summarizes their findings and is intended to present health care providers with the best possible information with which to help cancer survivors and their families make informed choices related to nutrition and physical activity. The report discusses nutrition and physical activity guidelines during the continuum of cancer care, briefly highlighting important issues during cancer treatment and for patients with advanced cancer, but focusing largely on the needs of the population of individuals who are disease free or who have stable disease following their recovery from treatment. It also discusses select nutrition and physical activity issues such as body weight, food choices, food safety, and dietary supplements; issues related to selected cancer sites; and common questions about diet, physical activity, and cancer survivorship.

Green tea for ovarian cancer prevention and treatment: a systematic review of the in vitro, in vivo and epidemiological studies

OBJECTIVE

This systematic review was conducted to examine the effects of green tea or green tea components on the prevention and progression of epithelial ovarian cancer.

METHODS

Using Medline, EMBASE and SciVerse (last researched: July 2011), we retrieved 22 articles including 5 epidemiological studies.

RESULTS

In epithelial ovarian cancer cell lines, green tea and green tea components have been shown to downregulate the expression of proteins involved in inflammation, cell signalization, cell motility and angiogenesis. Green tea and green tea components would induce apoptosis and could potentiate the effects of cisplatin, a chemotherapeutic agent. In human observational studies, significant associations between green tea intake and both decreased ovarian cancer occurrence and better prognosis were reported.

CONCLUSIONS

Available literature suggests potential molecular targets for green tea in ovarian cancer treatment and also provides data supporting the clinical evaluation of the role of green tea or green tea components in ovarian cancer prevention and treatment.

Recent advances on tea polyphenols

Over the past decade many scientific and medical studies have focused on green tea for its long-purported health benefits. There is convincing evidence that tea is a cup of life. It has multiple preventive and therapeutic effects. This review thus focuses on the recent advances of tea polyphenols and their applications in the prevention and treatment of human cancers. Of the various polyphenols in tea, (-)-Epigallocatechin-3-gallate (EGCG) is the most abundant, and active compound studied in tea research. EGCG inhibits several molecular targets to inhibit cancer initiation and modulates several essential survival pathways to block cancer progression. Herein, we describe the various mechanisms of action of EGCG and also discuss previous and current ongoing clinical trials of EGCG and green tea polyphenols in different cancer types.

A randomized parallel-group dietary study for stages II-IV ovarian cancer survivors

OBJECTIVE

Few studies have examined the dietary habits of ovarian cancer survivors. Therefore, we conducted a study to assess the feasibility and impact of two dietary interventions for ovarian cancer survivors.

METHODS

In this randomized, parallel-group study, 51 women (mean age, 53 years) diagnosed with stages II-IV ovarian cancer were recruited and randomly assigned to a low fat, high fiber (LFHF) diet or a modified National Cancer Institute diet supplemented with a soy-based beverage and encapsulated fruit and vegetable juice concentrates (FVJCs). Changes in clinical measures, serum carotenoid and tocopherol levels, dietary intake, anthropometry, and health-related quality of life (HRQOL) were assessed with paired t-tests.

RESULTS

The recruitment rate was 25%, and the retention rate was 75% at 6 months. At baseline, 28% and 45% of women met guidelines for intake of fiber and of fruits and vegetables, respectively. After 6 months, total serum carotenoid levels and α- and β-carotene concentrations were significantly increased in both groups (P<0.01); however, β-carotene concentrations were increased more in the FVJC group. Serum β-cryptoxanthin levels, fiber intake (+5.2g/day), and daily servings of juice (+0.9 servings/day) and vegetables (+1.3 servings/day) were all significantly increased in the LFHF group (all P<0.05). Serum levels of albumin, lutein and zeaxanthin, retinol, and retinyl palmitate were significantly increased in the FVJC group (all P<0.05). No changes in cancer antigen-125, anthropometry, or HRQOL were observed.

CONCLUSION

Overall, this study supports the feasibility of designing dietary interventions for stages II-IV ovarian cancer survivors and provides preliminary evidence that a low fat high fiber diet and a diet supplemented with encapsulated FVJC may increase phytonutrients in ovarian cancer survivors.

Green and black tea in relation to gynecologic cancers

SCOPE

Observational studies have evaluated the relationship between green tea intake and cancers of the ovary and endometrium, but we are not aware of the published studies on green tea intake and risk of human papillomavirus (HPV)-related cancers of the cervix, vagina, or vulva.

METHODS AND RESULTS

A critical review of the published literature on tea intake and risk of ovarian and endometrial cancers was conducted. In meta-analyses, we report inverse associations for green tea intake and risk of ovarian cancer (odds ratio [OR]=0.66; 95% confidence interval [CI]: 0.54, 0.80), and for green tea and risk of endometrial cancer (OR=0.78, 95% CI: 0.62, 0.98). There was no association for black tea and ovarian cancer risk (OR=0.94, 95% CI: 0.87, 1.02) and a positive association with endometrial cancer risk (OR=1.20, 95% CI: 1.05, 1.38). We summarized the experimental evidence supporting the antiviral and immunomodulatory activities of green tea catechins, and results from randomized clinical trials that demonstrated green tea catechin efficacy on treatment of cervical lesions and external genital warts.

CONCLUSION

Observational data support a protective role of green tea on risk of ovarian and endometrial cancers. Observational data are needed to evaluate whether green tea reduces risk of human papillomavirus-related cancers.

The chemopreventive properties and therapeutic modulation of green tea polyphenols in oral squamous cell carcinoma

Chemoprevention is a relatively novel and promising approach for controlling cancer that uses specific natural products or synthetic agents to suppress, reverse, or prevent premalignancy before transformation into invasive cancer. Oral cavity squamous cell carcinoma (OCSCC) represents a large, worldwide health burden with approximately 274,000 cases diagnosed annually worldwide. Smoking and alcohol consumption are major inducers of OCSCC. Recently, the human papilloma virus was also shown to potentially be an etiologic factor. Due to its easily identifiable risk factors and the presence of premalignant regions, oral cancer makes a good candidate for chemoprevention. Green tea is the most widely consumed beverage in the world, and it has received considerable attention because of its abundant, scientifically proven, beneficial effects on human health. In this review, we discuss the role of green tea in oral cancer chemoprevention with regard to the multiple molecular mechanisms proposed in various in vitro, in vivo, and clinical trials.

Nutritional factors in ovarian cancer survival

Ovarian cancer is the leading cause of death from gynecologic malignancies in the United States. Because symptoms tend be nonspecific, early detection is difficult, and most ovarian cancers are diagnosed at an advanced stage when the prognosis is poor. Nonetheless, there is clinical evidence that even given the same tumor characteristics (histologic type, stage, and grade), some cases experience much better survival than others. This has led to extensive research on molecular prognostic factors to enable more efficient and targeted therapeutic regimens. However, little is known about the impact that lifestyle factors, such as diet or physical activity, may have in the prognosis of ovarian cancer, whether on disease-free survival or on the response to and complications from treatment. The role of obesity on ovarian cancer survival is unclear. Obesity may delay diagnosis, hinder optimal surgical and cytotoxic treatment, and cause postoperative complications. As overweight and obesity rates reach epidemic proportions, the impact of body mass index in the clinical management of ovarian cancer is increasingly significant, whereas current evidence of its impact is limited and inconclusive.

Tea consumption and risk of endometrial cancer: a metaanalysis

OBJECTIVE

The objective of the study was to assess the association between tea consumption and endometrial cancer.

STUDY DESIGN

Studies were identified by searching PubMed and EMBASE databases and screening the references of retrieved articles. The summary relative risk (RR) with 95% confidence interval (CI) was calculated.

RESULTS

The combined RR for ever drinkers vs non/lowest drinkers was 0.85 (95% CI, 0.77-0.94). Compared with non/lowest drinkers, the summary RR was 0.88 (95% CI, 0.78-0.98) for low to moderate drinkers and 0.75 (95% CI, 0.64-0.88) for high drinkers. An increase in tea intake of 2 cups/day was associated with a 25% decreased risk of endometrial cancer. In subgroup analyses, tea consumption was significantly associated with reduced endometrial cancer risk in Asian studies and studies using interviewing techniques. Furthermore, the protective effect of green tea on endometrial cancer seemed more evident than that of black tea.

CONCLUSION

Findings from this metaanalysis suggest that tea consumption may reduce the risk of endometrial cancer. Because of the limited number of studies, further prospective studies are needed to explore the protective effect of tea on endometrial cancer.

Can green tea do that? A literature review of the clinical evidence

OBJECTIVE

Habitual green tea consumption has long been associated with health benefits including chemoprevention and cardiovascular protection. This non-systematic literature review presents the clinical evidence to date.

METHOD

A literature review of peer-reviewed articles on observational and interventional studies was conducted to include green tea, its extract or its purified polyphenol (-)-epigallocatechin-3-gallate (EGCG). Electronic databases searched included PubMed (1966-2009) and the Cochrane Library (Issue 4, 2008).

RESULTS

Observational studies are inconclusive on the benefits of habitual consumption of green tea in the prevention of most cancers. However, there are trends towards prevention in breast and prostate cancers. Interventional studies have demonstrated reduction in relapses following surgical resection in colorectal adenomas and increased survival rates in epithelial ovarian cancer. Observational studies indicate that green tea may provide protection against hypertension and reduce the risk for stroke, and interventional studies are providing biochemical and physiological evidence.

CONCLUSION

Although the overall clinical evidence is inconclusive, habitual green tea consumption may be providing some level of chemoprevention in prostate and breast cancer. Green tea may also attenuate the risk factors association with the development of atherosclerosis thus reducing the incidence of cardiovascular events and stoke.

Green tea (Camellia sinensis) for the prevention of cancer

BACKGROUND

Tea is one of the most commonly consumed beverages worldwide. Teas from the plant Camellia sinensis can be grouped into green, black and oolong tea. Cross-culturally tea drinking habits vary. Camellia sinensis contains the active ingredient polyphenol, which has a subgroup known as catechins. Catechins are powerful antioxidants. It has been suggested that green tea polyphenol may inhibit cell proliferation and observational studies have suggested that green tea may have cancer-preventative effects.

OBJECTIVES

To critically assess any associations between green tea consumption and the risk of cancer incidence and mortality.

SEARCH STRATEGY

We searched eligible studies up to January 2009 in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Amed, CancerLit, Psych INFO and Phytobase and reference lists of previous reviews and included studies.

SELECTION CRITERIA

We included all prospective, controlled interventional studies and observational studies, which either assessed the associations between green tea consumption and risk of cancer incidence or that reported on cancer mortality.

DATA COLLECTION AND ANALYSIS

At least two review authors independently applied the study criteria, extracted data and assessed methodological quality of studies. Due to the nature of included studies, which were mainly epidemiological, results were summarised descriptively according to cancer diagnosis.

MAIN RESULTS

Fifty-one studies with more than 1.6 million participants were included. Twenty-seven of them were case-control studies, 23 cohort studies and one randomised controlled trial (RCT).Twenty-seven studies tried to establish an association between green tea consumption and cancer of the digestive tract, mainly of the upper gastrointestinal tract, five with breast cancer, five with prostate cancer, three with lung cancer, two with ovarian cancer, two with urinary bladder cancer one with oral cancer, three further studies included patients with various cancer diagnoses.The methodological quality was measured with the Newcastle-Ottawa scale (NOS). The 9 nested case-control studies within prospective cohorts were of high methodological quality, 13 of medium, and 1 of low. One retrospective case-control study was of high methodological quality and 21 of medium and 5 of low.Results from studies assessing associations between green tea and risk of digestive tract cancer incidence were highly contradictory. There was limited evidence that green tea could reduce the incidence of liver cancer. The evidence for esophageal, gastric, colon, rectum, and pancreatic cancer was conflicting. In prostate cancer, observational studies with higher methodological quality and the only included RCT suggested a decreased risk in men consuming higher quantities green tea or green tea extracts. However, there was limited to moderate evidence that the consumption of green tea reduced the risk of lung cancer, especially in men, and urinary bladder cancer or that it could even increase the risk of the latter. There was moderate to strong evidence that green tea consumption does not decrease the risk of dying from gastric cancer. There was limited moderate to strong evidence for lung, pancreatic and colorectal cancer.

AUTHORS' CONCLUSIONS

There is insufficient and conflicting evidence to give any firm recommendations regarding green tea consumption for cancer prevention. The results of this review, including its trends of associations, need to be interpreted with caution and their generalisability is questionable, as the majority of included studies were carried out in Asia (n = 47) where the tea drinking culture is pronounced. Desirable green tea intake is 3 to 5 cups per day (up to 1200 ml/day), providing a minimum of 250 mg/day catechins. If not exceeding the daily recommended allowance, those who enjoy a cup of green tea should continue its consumption. Drinking green tea appears to be safe at moderate, regular and habitual use.

Green tea (Camellia sinensis) for the prevention of cancer

BACKGROUND

Tea is one of the most commonly consumed beverages worldwide. Teas from the plant Camellia sinensis can be grouped into green, black and oolong tea. Cross-culturally tea drinking habits vary. Camellia sinensis contains the active ingredient polyphenol, which has a subgroup known as catechins. Catechins are powerful antioxidants. It has been suggested that green tea polyphenol may inhibit cell proliferation and observational studies have suggested that green tea may have cancer-preventative effects.

OBJECTIVES

To critically assess any associations between green tea consumption and the risk of cancer incidence and mortality.

SEARCH STRATEGY

We searched eligible studies up to January 2009 in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Amed, CancerLit, Psych INFO and Phytobase and reference lists of previous reviews and included studies.

SELECTION CRITERIA

We included all prospective, controlled interventional studies and observational studies, which either assessed the associations between green tea consumption and risk of cancer incidence or that reported on cancer mortality.

DATA COLLECTION AND ANALYSIS

At least two review authors independently applied the study criteria, extracted data and assessed methodological quality of studies. Due to the nature of included studies, which were mainly epidemiological, results were summarised descriptively according to cancer diagnosis.

MAIN RESULTS

Fifty-one studies with more than 1.6 million participants were included. Twenty-seven of them were case-control studies, 23 cohort studies and one randomised controlled trial (RCT).Twenty-seven studies tried to establish an association between green tea consumption and cancer of the digestive tract, mainly of the upper gastrointestinal tract, five with breast cancer, five with prostate cancer, three with lung cancer, two with ovarian cancer, two with urinary bladder cancer one with oral cancer, three further studies included patients with various cancer diagnoses.The methodological quality was measured with the Newcastle-Ottawa scale (NOS). The 9 nested case-control studies within prospective cohorts were of high methodological quality, 13 of medium, and 1 of low. One retrospective case-control study was of high methodological quality and 21 of medium and 5 of low.Results from studies assessing associations between green tea and risk of digestive tract cancer incidence were highly contradictory. There was limited evidence that green tea could reduce the incidence of liver cancer. The evidence for esophageal, gastric, colon, rectum, and pancreatic cancer was conflicting. In prostate cancer, observational studies with higher methodological quality and the only included RCT suggested a decreased risk in men consuming higher quantities green tea or green tea extracts. However, there was limited to moderate evidence that the consumption of green tea reduced the risk of lung cancer, especially in men, and urinary bladder cancer or that it could even increase the risk of the latter. There was moderate to strong evidence that green tea consumption does not decrease the risk of dying from gastric cancer. There was limited moderate to strong evidence for lung, pancreatic and colorectal cancer.

AUTHORS' CONCLUSIONS

There is insufficient and conflicting evidence to give any firm recommendations regarding green tea consumption for cancer prevention. The results of this review, including its trends of associations, need to be interpreted with caution and their generalisability is questionable, as the majority of included studies were carried out in Asia (n = 47) where the tea drinking culture is pronounced. Desirable green tea intake is 3 to 5 cups per day (up to 1200 ml/day), providing a minimum of 250 mg/day catechins. If not exceeding the daily recommended allowance, those who enjoy a cup of green tea should continue its consumption. Drinking green tea appears to be safe at moderate, regular and habitual use.

The potential role of green tea catechins in the prevention of the metabolic syndrome - a review

The metabolic syndrome (MetS) represents an emerging health burden for governments and health care providers. Particularly relevant for prevention and early management of MetS are lifestyle conditions including physical activity and the diet. It has been shown that green tea, when consumed on a daily basis, supports health. Many of the beneficial effects of green tea are related to its catechin, particularly (-)-epigallocatechin-3-gallate (EGCG), content. There is conclusive evidence from in vitro and animal studies which provide the concepts for underlying functional mechanisms of green tea catechins and their biological actions. An increasing number of human studies have explored the effects of green tea catechins on the major MetS conditions such as obesity, type-2 diabetes and cardiovascular risk factors. This article provides a comprehensive overview of the human studies addressing the potential benefits of green tea catechins on the MetS. The number of human studies in this field is still limited. However, the majority of human epidemiological and intervention studies demonstrate beneficial effects of green tea or green tea extracts, rich in EGCG on weight management, glucose control and cardiovascular risk factors. The optimal dose has not yet been established. The current body of evidence in humans warrants further attention. In particular, well-controlled long-term human studies would help to fully understand the protective effects of green tea catechins on parameters related to the MetS.

Green tea (Camellia sinensis) and cancer prevention: a systematic review of randomized trials and epidemiological studies

BACKGROUND

Green tea is one of the most popular beverages worldwide. This review summarizes the beneficial effects of green tea on cancer prevention.

METHODS

Electronic databases, including PubMed (1966-2008), the Cochrane Library (Issue 1, 2008) and Chinese Biomedical Database (1978-2008) with supplement of relevant websites, were searched. There was no language restriction. The searches ended at March 2008. We included randomized and non-randomized clinical trials, epidemiological studies (cohort and case-control) and a meta-analysis. We excluded case series, case reports, in vitro and animal studies. Outcomes were measured with estimation of relative risk, hazard or odd ratios, with 95% confidence interval.

RESULTS

Forty-three epidemiological studies, four randomized trials and one meta-analysis were identified. The overall quality of these studies was evaluated as good or moderate. While some evidence suggests that green tea has beneficial effects on gastrointestinal cancers, the findings are not consistent.

CONCLUSION

Green tea may have beneficial effects on cancer prevention. Further studies such as large and long term cohort studies and clinical trials are warranted.

Tea or coffee? A case study on evidence for dietary advice

The present paper explores the level of evidence required to justify giving dietary advice to the public. There are important practical differences between the development of public health nutrition guidelines and guidelines for clinical practice. While the gold standard for evidence for clinical practice guidelines is a meta-analysis of a number of randomised controlled trials, this is often unrealistic and sometimes unethical for the evaluation of public health nutrition interventions. Hence, epidemiological studies make up the bulk of evidence for nutrition guidelines. Tea and coffee are an interesting case study in relation to this issue. They are two of the most commonly consumed beverages worldwide, yet there is little dietary advice on their use. The evidence for a relationship between coffee or tea consumption and several diseases is discussed. The available studies, predominantly epidemiological, together with animal and in vitro studies, indicate that coffee and tea are both safe beverages. However, tea is the healthier option because it has a possible role in the prevention of several cancers and CVD. While the evidence for such relationships is not strong, the public will continue to drink both tea and coffee, and will continue to ask nutritionists to make recommendations. It is therefore argued that advice should be given on the best available data, as waiting for complete data to become available could have severe consequences for public health.

Possible protective effect of green tea intake on risk of adult leukaemia

In a case–control study of 107 adults with leukaemia and 110 orthopaedic controls in China, a reduced risk was found with longer duration, higher quantity, and frequency of green tea intake.

The association of tea consumption with ovarian cancer risk: A metaanalysis

OBJECTIVE

This metaanalysis was undertaken to evaluate the relationship between tea intake and ovarian cancer risk.

STUDY DESIGN

A systematic literature search up to September 2006 was performed in Medline, Embase, CANCERLIT, and the Cochrane Database. The summary relative risk was calculated. A sensitivity analysis was conducted to test the influence of each single study. Heterogeneity and publication bias were also evaluated.

RESULTS

Two cohort and 7 case-control studies were included. The combined relative risk did not show that tea consumption was associated with a reduced ovarian cancer risk (relative risk, 0.84; 95% confidence interval, 0.66-1.07). When the analyses were stratified into subgroups, there was no evidence that study design substantially influenced the estimate of effects. The sensitivity analysis which means removing one study at a time confirmed the stability of our results.

CONCLUSION

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

Possible role for green tea in ovarian cancer prevention

Ovarian cancer is the leading cause of death from gynecologic cancer. Tea, especially green tea, has shown promise in the prevention of several cancers. Green tea contains a number of compounds, including polyphenols, that have chemopreventive properties. There is much evidence from in vitro and animal studies suggesting that components of tea are associated with decreased risk or progression of ovarian cancer. However, epidemiologic studies have generated inconsistent results. Recent research conducted in China reported reduced risk of ovarian cancer and increased survival post diagnosis with green tea consumption. This review presents emerging evidence and the authors' perspectives on the role of green tea in ovarian cancer prevention.

The effect of lifestyle factors on gynaecological cancer

Several lifestyle factors affect a woman's risk of gynaecological cancer and-potentially-can be modified to reduce risk. This chapter summarises the evidence for the effect of lifestyle factors on the incidence of gynaecological malignancy. The incidence of obesity is increasing in the developed world such that it now contributes as much as smoking to overall cancer deaths. Women with a body mass index (BMI)>40 have a 60% higher risk of dying from all cancers than women of normal weight. They are also at increased risk from gynaecological cancer. Dietary factors significantly influence the risk of gynaecological cancer: fruit, vegetables and antioxidants reduce risk whereas high animal fat and energy intakes increase risk. Alcohol intake adversely affects breast cancer risk, possibly accounting for 4% of all breast cancers. Physical activity protects against ovarian, endometrial and postmenopausal breast cancer, independently of BMI. The oral contraceptive pill has a substantial and long-lasting effect on the prevention of ovarian and endometrial cancer and is one of the best examples of large-scale chemoprevention in the developed world. Childbearing is protective against ovarian, endometrial and breast cancer but increases the risk of cervical cancer. Smoking acts as a cofactor in cervical carcinogenesis and increases the risk of ovarian cancer, particularly mucinous tumours.

Does the consumption of green tea reduce the risk of lung cancer among smokers?

Experimental and epidemiological studies were reviewed to assess whether the consumption of green tea could reduce the risk of lung cancer in smokers. Articles published since 1990 were located by searching electronic databases PubMed, Ovid and Science Direct, using keywords 'lung cancer', 'tea' and 'smoking' without any restriction on language. After relevant articles had been located, further papers were obtained from their reference lists. Evidence from experimental studies (in vitro animal and human trials) suggested that regular intake of green tea may be protective against tobacco carcinogens. However, the mechanism behind the protective effect is only partly understood. In most of the epidemiological studies reviewed, the green tea exposure was within 5 years of the interview or follow-up, which would coincide with the induction period and latent period of lung cancer. Longer term studies are thus needed to further quantify the cancer risk. There is some evidence suggesting regular intake of green tea at high level (>3 cups per day) may reduce the risk of smokers developing lung cancer. Improvement in measuring green tea intake is required in order to confirm the evidence from epidemiological studies.

Inhibition of matrix metalloproteinase-2 secretion and invasion by human ovarian cancer cell line SK-OV-3 with lysine, proline, arginine, ascorbic acid and green tea extract

AIMS

Based on the poor prognosis associated with ovarian cancer and reported anticancer properties of specific nutrients, we investigated the effect of a nutrient mixture (NM) containing lysine, proline, arginine, ascorbic acid and epigallocatechin gallate on human ovarian cancer cells SK-OV-3 by measuring: cell proliferation, modulation of matrix metalloproteinase (MMP)-2 and -9 expression, and cancer cell invasive potential.

METHODS

Cell proliferation was evaluated by MTT assay, MMP activity by gelatinase zymography, and invasion through Matrigel.

RESULTS

Human ovarian cancer cell growth was not significantly affected by the NM. Zymography demonstrated inhibition of MMP-2 secretion in a dose-dependent fashion with virtual total inhibition at 50 microg/mL NM concentration. Invasion of human ovarian cancer cells through Matrigel decreased in a dose-dependent fashion, with 90% inhibition at 500 microg/mL NM and 100% inhibition at 1000 microg/mL NM (P < 0.0001).

CONCLUSION

The combination of lysine, proline, arginine, ascorbic acid and green tea extract tested inhibited critical steps in cancer development and spread, such as MMP expression and invasion, indicating its potential as a treatment modality against ovarian cancer.

Complementary and alternative medicine for advanced prostate cancer

Complimentary and alternative medicines (CAM) have increased drastically in popularity in the past decade. These are largely in the form of nutritional supplements. Despite a wealth of information sources on the subject, the fundamental problem with CAM therapies is a dearth of evidence-based medicine. Advanced prostate cancer has significant long-term morbidity, and there is a growing interest in alternative and complimentary forms of therapy that will improve the outcomes of patients who have recurrent or advanced prostate cancer while obviating the need for more toxic forms of therapy. In this article we summarize the use of some of the more common CAM nutritional supplements and review the scientific data that are available to support their use.

Green tea polyphenol epigallocatechin-3-gallate inhibits the endothelin axis and downstream signaling pathways in ovarian carcinoma

The polyphenol epigallocatechin-3-gallate (EGCG), the principal mediator of the green tea, has been known to possess antitumor effect. The endothelin A receptor (ET(A)R)/endothelin-1 (ET-1) axis is overexpressed in ovarian carcinoma representing a novel therapeutic target. In this study, we examined the green tea and EGCG effects on two ovarian carcinoma cell lines, HEY and OVCA 433. EGCG inhibited ovarian cancer cell growth and induced apoptosis that was associated with a decrease in Bcl-X(L) expression and activation of caspase-3. Treatment with green tea or EGCG inhibited ET(A)R and ET-1 expression and reduced the basal and ET-1-induced cell proliferation and invasion. The EGCG-induced inhibitory effects were associated with a decrease of ET(A)R-dependent activation of the p42/p44 and p38 mitogen-activated protein kinases and phosphatidylinositol 3-kinase pathway. Remarkably, EGCG treatment resulted in a lowering of basal and ET-1-induced angiogenesis and invasiveness mediators, such as vascular endothelial growth factor and tumor proteinase activation. Finally, in HEY ovarian carcinoma xenografts, tumor growth was significantly inhibited by oral administration of green tea. This effect was associated with a reduction in ET-1, ET(A)R, and vascular endothelial growth factor expression, microvessel density, and proliferation index. These results provide a novel insight into the mechanism by which EGCG, affecting multiple ET(A)R-dependent pathways, may inhibit ovarian carcinoma growth, suggesting that EGCG may be useful in preventing and treating ovarian carcinoma in which ET(A)R activation by ET-1 plays a critical role in tumor growth and progression.

Epigallocatechin-3-gallate delivers hydrogen peroxide to induce death of ovarian cancer cells and enhances their cisplatin susceptibility

The green tea polyphenol epigallocatechin-3-gallate (EGCG) has cancer chemopreventive properties against various types of cancers. The compound is known to attack various targets in transformed cells. In this report, we examined the action of EGCG on ovarian cancer cells. Eight ovarian cancer cell lines were tested (SKOV3, CAOV3, OVCAR3, OVCAR10, A2780, CP70, C30, and C200) and showed IC50s for EGCG at the micromolar range, including ones that are resistant to the chemotherapeutic drug cisplatin. The ovarian cancer cells were sensitive to H2O2 at similar concentrations, and EGCG treatment led to enhanced intracellular H2O2. Neutralization with pyruvate, a scavenger of H2O2, suggests that the toxicity of EGCG may be mediated by oxidative stress from the free radical. Addition of Tempol, a superoxide dismutase mimetic, demonstrates that H2O2 might be generated endogenously from superoxide. The toxicity of cisplatin and the development of cisplatin resistance are major obstacles in treatment of ovarian cancer. We found that addition of EGCG amplified the toxicity of cisplatin. EGCG increased cisplatin potency by three to six-fold in SKOV3, CAOV3, and C200 cells, the latter being a cell line induced to have several hundred fold resistant to cisplatin above the parental line. Our findings suggest that EGCG may accentuate oxidative stress to inhibit growth of ovarian cancer cells and sensitize them to cisplatin.

Tea, hormone-related cancers and endogenous hormone levels

Tea is one of the most popular beverages consumed around the world, second only to water. There has been substantial interest in the potential role of tea in cancer prevention, particularly in respiratory and gastrointestinal tract cancers. Recent epidemiological data have linked tea intake to reduced risk of hormone-related cancers, including breast, ovarian and prostate cancers. Based on sparse data, there is suggestion that tea intake may influence circulating hormone levels, providing a plausible mechanism whereby tea intake may influence risk of hormone-related cancers. The major objectives of this paper are to review the epidemiological evidence on tea and risk of breast, ovarian, and prostate cancers as well as the human and non-human studies on tea and circulating hormone levels. We pay special attention to some of the limitations of the human studies and discuss future research needs.

A Gene Expression Signature that Can Predict Green Tea Exposure and Chemopreventive Efficacy of Lung Cancer in Mice

Green tea has been shown to be a potent chemopreventive agent against lung tumorigenesis in animal models. Previously, we found that treatment of A/J mice with either green tea (0.6% in water) or a defined green tea catechin extract (polyphenon E; 2.0 g/kg in diet) inhibited lung tumor tumorigenesis. Here, we described expression profiling of lung tissues derived from these studies to determine the gene expression signature that can predict the exposure and efficacy of green tea in mice. We first profiled global gene expressions in normal lungs versus lung tumors to determine genes which might be associated with the tumorigenic process (TUM genes). Gene expression in control tumors and green tea-treated tumors (either green tea or polyphenon E) were compared to determine those TUM genes whose expression levels in green tea-treated tumors returned to levels seen in normal lungs. We established a 17-gene expression profile specific for exposure to effective doses of either green tea or polyphenon E. This gene expression signature was altered both in normal lungs and lung adenomas when mice were exposed to green tea or polyphenon E. These experiments identified patterns of gene expressions that both offer clues for green tea's potential mechanisms of action and provide a molecular signature specific for green tea exposure.

Comparison of (-)-epigallocatechin-3-gallate elicited liver and small intestine gene expression profiles between C57BL/6J mice and C57BL/6J/Nrf2 (-/-) mice

PURPOSE

This study was conducted to study global gene expression profiles elicited by (-)-epigallocatechin-3-gallate (EGCG) in mouse liver and small intestine, as well as to identify EGCG-regulated Nrf2-dependent genes.

METHODS

C57BL/6J and C57BL/6J/Nrf2(-/-) mice were given an oral dose of EGCG at 200 mg/kg or treated with vehicle. Both liver and small intestine were collected 3 h and 12 h after treatment. Total RNA was extracted from the tissues and gene expression profiles were analyzed using Affymetrix mouse genome 430 2.0 array and GeneSpring 6.1 software. Microarray data were validated using quantitative real-time reverse transcription-PCR chain reaction analysis.

RESULTS

Genes that were either induced or suppressed more than two fold by EGCG treatment compared with vehicle treatment in the same genotype group were filtered using the GeneSpring software. Among these well-defined genes, 671 EGCG-regulated Nrf2-dependent genes and 256 EGCG-regulated Nrf2-independent genes were identified in liver, whereas 228 EGCG-regulated Nrf2-dependent genes and 98 EGCG-regulated Nrf2-independent genes were identified in the small intestine. Based on their biological functions, these genes mainly fall into the category of ubiquitination and proteolysis, electron transport, detoxification, transport, cell growth and apoptosis, cell adhesion, kinase and phosphatases, and transcription factors.

CONCLUSIONS

Genes expressed in mouse liver are more responsive to oral treatment of EGCG than those expressed in small intestine. EGCG could regulate many genes in both organs in an Nrf2-dependent manner. The identification of genes related to detoxification, transport, cell growth and apoptosis, cell adhesion, kinase, and transcription regulated by EGCG not only provide potential novel insight into the effect of EGCG on global gene expression and chemopreventive effects, but also point to the potential role of Nrf2 in these processes.