Patients' perceptions of research biopsies in Phase I Oncology Trials

Objective: Research biopsies are increasingly incorporated into phase I oncology trials resulting in ethical and logistical challenges for patients and clinicians. Patients' understanding and willingness to undergo these biopsies are crucial. Methods: Over 12 months, we administered a questionnaire comprising three sections: demographics and previous cancer therapy, understanding of phase I trials and personalized medicine, and understanding of biopsies and associated risks. Results: Out of 56 patients approached, 47 patients completed the questionnaire. Overall, the patients were well informed about the concepts of personalized medicine and 89% (n = 42) were aware that early phase clinical trials aim to define a dose and explore side effects of new drugs. Interestingly, 76% (n = 36) expected early phase trials to improve symptoms, quality of life and survival. Offering hope and feeling in control of their treatment were important components for 80% (n = 38) and 57% (n = 27), respectively. The majority of this highly selective patient cohort understood the concept of research biopsies, with 59% (n = 28) willing to have a fresh research biopsy for trial participation. Although 72% (n = 34) felt that research biopsies should be optional, only 19% (n = 9) would not participate in a clinical trial with mandatory biopsies. Compared to diagnostic biopsies, the patients were less likely to accept associated risks with research biopsies. Conclusion: As research biopsies are crucial to many components of the drug development process, our study provides evidence for patients' overall willingness to undergo research biopsies for trial purposes. A consent process tailored to the biopsy site may help patients weigh up the associated risks versus benefits

Dose-Dependent Levels of Epigallocatechin-3-Gallate in Human Colon Cancer Cells and Mouse Plasma and Tissues

Epigallocatechin-3-gallate (EGCG; molecular formula: C22H 18011) is the most abundant catechin in green tea (Camellia sinensis Theaceae). Both EGCG and green tea have been shown to have cancer-preventive activity in a number of animal models, and numerous mechanisms have been proposed based on studies with human cell lines. EGCG has been shown to undergo extensive biotransformation to yield methylated and glucuronidated metabolites in mice, rats, and humans. In the present study, we determined the concentration-dependent uptake of EGCG by HT-29 human colon cancer cells (20-600 μM) and the dose dependence of EGCG plasma and tissue levels after a single dose of EGCG (50-2000 mg/kg i.g.) to male CF-1 mice. The cytosolic levels of EGCG were linear with respect to extracellular concentration of EGCG after treatment of HT-29 cells for 2 h (915.3-6851.6 μg/g). In vivo, EGCG exhibited a linear dose relationship in the plasma (0.03-4.17 μg/ml), prostate (0.01-0.91 μg/g), and liver (0.09- 18.3 μg/g). In the small intestine and colon, however, the levels of EGCG plateaued between 500 and 2000 mg/kg i.g. These results suggest that absorption of EGCG from the small intestine is largely via passive diffusion; however, at high concentrations, the small intestinal and colonic tissues become saturated. The levels of 4″-O-methyl-EGCG and 4′,4″-di-O-methyl-EGCG parallel those of EGCG with respect to dose. The present study provides information with respect to what concentrations of EGCG are achievable in mice and may guide dose selection for future cancer chemoprevention studies with EGCG

Laboratory, Epidemiological, and Human Intervention Studies Show That Tea (Camellia sinensis) May Be Useful in the Prevention of Obesity12

Tea (Camellia sinensis, Theaceae) and tea polyphenols have been studied for the prevention of chronic diseases, including obesity. Obesity currently affects >20% of adults in the United States and is a risk factor for chronic diseases such as type II diabetes, cardiovascular disease, and cancer. Given this increasing public health concern, the use of dietary agents for the prevention of obesity would be of tremendous benefit. Whereas many laboratory studies have demonstrated the potential efficacy of green or black tea for the prevention of obesity, the underlying mechanisms remain unclear. The results of human intervention studies are mixed and the role of caffeine has not been clearly established. Finally, there is emerging evidence that high doses of tea polyphenols may have adverse side effects. Given that the results of scientific studies on dietary components, including tea polyphenols, are often translated into dietary supplements, understanding the potential toxicities of the tea polyphenols is critical to understanding their potential usefulness in preventing obesity. In this review, we will critically evaluate the evidence for the prevention of obesity by tea, discuss the relevance of proposed mechanisms in light of tea polyphenol bioavailability, and review the reports concerning the toxic effects of high doses of tea polyphenols and the implication that this has for the potential use of tea for the prevention of obesity. We hope that this review will expose areas for further study and encourage research on this important public health issue