前列腺癌的化学预防

前列腺癌的化学预防是一种相对全新的概念。本文就食物干预或药物治疗与前列腺癌预防关系的研究现状作一扼要介绍。     

绿茶预防肝癌的系列动物实验研究

为了较全面了了解绿茶对黄曲霉素Ｂ１诱发肝癌的防护作用，应用ＡＦＢ１致肝癌作用动物实验模型，对绿茶在ＡＦＢ１致肝癌作用方面的影响从多个角度进行了一系列的实验探讨，所有实验结果一致显示绿茶对ＡＦＢ１的致肝癌作用具有明显的抑制效果，从而展示展现了绿茶作为一种安全，可靠，有效的化学预防物的广阔应用前景。     

绿茶对肝细胞癌变的抑制性效果

一、一般性介绍茶是世界性的饮料 ,一般可分为 3个大类 :绿茶 ,红茶 ,乌龙茶。后两者由于发酵或部分发酵而损失了部分药效。绿茶中有如下成分 :类胡萝卜素 ,叶绿素 ,多糖 ,氨基酸 ,脂肪 ,金属酶 ,维生素Ｃ ,维生素Ｅ ,咖啡因 ,鞣酸 ,皂角甙 ,锰 ,钾 ,锌 ,茶多酚。茶多酚是类黄酮家族的成员。绿茶中 ,有四种茶多酚 ,都是有多环结构的儿茶素 :表儿茶素 (ＥＣ) ,表没食子儿茶素 (ＥＧＣ) ,表儿茶素没食子酸盐(ＥＣＧ) ,表没食子儿茶素没食子酸盐 (ＥＧＣＧ)。ＥＧＣＧ在绿茶的茶多酚中占了约一半 ,是一种已知的抗氧化剂[1] 。儿茶素Ｂ环中邻位…     

茶叶和茶多酚与肿瘤的化学预防作用

茶叶和茶多酚与肿瘤的化学预防作用潘宏铭，郑树，吴金民浙江医科大学肿瘤研究所（杭州３１０００９）茶叶（Ｔｅａ，Ｃａｍｅｌｌｉａｓｉｎｅｎｓｉｓ）首先由我国发现和利用，现已有３０多个国家栽培，每年生产茶叶２５０万吨，行销世界各地，是世界上最受人们推崇的无...     

癌化学预防研究进展

癌化学预防研究进展中国医学科学院、中国协和医科大学肿瘤研究所流行病室（１０００２１）陈瑞娣癌化学预防是指用化学药物干预或阻断癌变的过程，使肿瘤分化逆转，从而达到预防癌症的目的。一、癌化学预防剂的研究１．癌化学预防药的重要进展之一是发现不少可防止实验性...     

绿茶预防肝癌的系列动物实验研究

为了较全面地了解绿茶对黄曲霉素Ｂ１（ＡＦＢ１）诱发肝癌的防护作用，应用ＡＦＢ１致肝癌作用动物实验模型，对绿茶在ＡＦＢ１致肝癌作用方面的影响从多个角度进行了一系列的实验探讨。所有实验结果一致显示绿茶对ＡＦＢ１的致肝癌作用具有明显的抑制效果，从而展现了绿茶作为一种安全、可靠、有效的化学预防物的广阔应用前景。     

Green tea compounds in breast cancer prevention and treatment

Breast cancer is the most common cancer among women. In recent years, many in vitro and in vivo studies indicate that green tea possesses anti-cancer effects. The epidemiological studies, however, have produced inconclusive results in humans. Likewise, results from animal models about the preventive or therapeutic effects of green tea components are inconclusive. The mechanisms by which green tea intake may influence the risk of breast cancer in humans remain elusive mechanisms by which green tea intake may influence. Here, we review recent studies of green tea polyphenols and their applications in the prevention and treatment of breast cancer. Furthermore, we discuss the effect of green tea components on breast cancer by reviewing epidemiological studies, animal model studies and clinical trials. At last, we discuss the mechanisms by which green tea components suppress the development and recurrence of breast cancer. A better understanding of the mechanisms will improve the utilization of green tea in breast cancer prevention and therapy and pave the way to novel prevention and treatment strategies for breast cancer.     

Green tea catechins suppress the DNA synthesis marker MCM7 in the TRAMP model of prostate cancer

Green tea catechins (GTCs) exert chemopreventive effects in many cancer models. Several studies implicate the DNA synthesis marker minichromosome maintenance protein 7 (MCM7) in prostate cancer progression, growth and invasion; representing a novel therapeutic target. In this study, we investigated the effect of GTCs on MCM7 expression in the transgenic adenocarcinoma mouse prostate model (TRAMP). DNA microarray, immunohistochemistry and western blot analysis showed that GTCs significantly suppressed MCM7 in the TRAMP mice treated with GTCs. Our study indicates that the cellular DNA replication factor MCM7 is involved in prostate cancer (CaP) and MCM7 gene expression was reduced by GTCs. Together, these results suggest a possible role of GTCs in CaP chemoprevention in which MCM7 plays a critical role.     

Dietary agents for chemoprevention of prostate cancer

Prostate cancer (CaP) is the leading cause of cancer-related deaths in American men, responsible for over 29,000 deaths in the year 2007. Chemoprevention is a plausible and cost-effective approach to reduce cancer morbidity and mortality through inhibition of precancerous events before the occurrence of clinical disease. Indeed, CaP is an ideal candidate disease for chemopreventive intervention as it is typically diagnosed in the elderly population with a relatively slower rate of growth and progression. The potential of dietary substances to act as chemopreventive agents against CaP is increasingly appreciated. Further, epidemiological studies have identified significant correlations between CaP incidence and dietary habits. It is hoped that, combining the knowledge based on agents with targets, we will be able to build an armamentarium of naturally occurring chemopreventive substances that could prevent or slow down the development and progression of CaP. In this review, we have summarized the findings from clinical and preclinical studies on dietary agents including green tea, pomegranate, lupeol, fisetin, and delphinidin that are currently being investigated in our laboratory for their chemopreventive potential against CaP.     

Green tea, black tea consumption and risk of lung cancer: A meta-analysis

Studies investigating the association of green tea and black tea consumption with lung cancer risk have reported inconsistent findings. To provide a quantitative assessment of this association, we conducted a meta-analysis on the topic. Studies were identified by a literature search in PubMed from 1966 to November 2008 and by searching the reference lists of relevant studies. Summary relative risk (RR) estimates and their corresponding 95% confidence intervals (CIs) were calculated based on random-effects model. Our meta-analysis included 22 studies provided data on consumption of green tea or black tea, or both related to lung cancer risk. For green tea, the summary RR indicated a borderline significant association between highest green tea consumption and reduced risk of lung cancer (RR = 0.78, 95% CI = 0.61–1.00). Furthermore, an increase in green tea consumption of two cups/day was associated with an 18% decreased risk of developing lung cancer (RR = 0.82, 95% CI = 0.71–0.96). For black tea, no statistically significant association was observe through the meta-analysis (highest versus non/lowest, RR = 0.86, 95% CI = 0.70–1.05; an increment of two cups/day, RR = 0.82, 95% CI = 0.65–1.03). In conclusion, our data suggest that high or an increase in consumption of green tea but not black tea may be related to the reduction of lung cancer risk.     

Green tea drinking habits and gastric cancer in southwest China

Aim: The purpose of this study was to investigate relationships between green tea consumption and gastric cancer development. Methods: A population-based case-control study including 200 cases and 200 controls was conducted in the southwest area of China from May 2010 to February 2011. A self-designed questionnaire was used to collect data on factors influencing gastric cancer development, including tea drinking, conditional logistic regression being used to calculate odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs). Results: Cases with higher economic status had a reduced risk of gastric cancer, while those with cancer family history, drinking and smoking showed increased risk. Hot and very hot tea temperature was significantly related to high risk of gastric cancer with ORs (95%Cl) of 1.82 (1.03-3.52) and 3.07 (1.78-7.36), respectively. Further analysis indicated elevated risk of gastric cancer in former drinkers, former smokers and current drinkers when the measured tea temperature was hot. Conclusion: Drinking tea at high temperature increases the gastric cancer risk, especially in drinkers and smokers.     

Green tea catechin as a chemical chaperone in cancer prevention

Green tea catechins have recently gained significant acceptance as a cancer preventive, and one of the important features of catechins is their interactions with various target molecules. We recently found a functional and structural similarity between catechins and chaperones: Stochastic conformational analysis in silico revealed numerous conformations of (-)-epigallocatechin gallate, (-)-epicatechin gallate and (-)-epigallocatechin, showing a unique flexibility and mobility of the catechin molecules and suggesting the significance of a galloyl group in conformational variation. Since these conformations result in interaction with various types of molecules, we think that green tea catechin induces cancer preventive activity mediated through a chaperone-like property.     

Pancreatic cancer chemoprevention by phytochemicals

Pancreatic cancer is fourth leading cause of cancer-related deaths in the United States of America. In spite of recent advances in the current therapeutic modalities such as surgery, radiation and chemotherapy patients, the average five year survival rate remains still less than 5%. Recently, compounds from natural sources receive ample of attention as anti-cancer agents. Many epidemiological studies published over the past few decades provide a strong correlation between consumption of vegetables, fruits or plant derived products and reduced incidence of cancer. The present review focuses on the potential antitumor effects of various natural products.     

应用前列腺特异抗原筛查诊断前列腺癌的临床意义

目的 探讨应用前列腺特异抗原(PSA)筛查诊断前列腺癌的临床意义.方法 对年龄≥50岁的8562例男性体检者进行PSA筛查,对血清PSA≥4.0 ng/ml者建议进行经直肠前列腺系统活检,活检病理确诊为前列腺癌的患者人选筛查组,记录其临床病理特点,并与同时期临床诊治的82例前列腺癌患者(临床组)进行比较.结果 在8562例进行血清PSA筛查的男性中,有719例血清PSA水平≥4.0 ng/ml,其中295例接受经直肠前列腺系统活检,共检出前列腺癌58例,活检率和活检阳性率分别为41.0%和19.7%.虽然两组患者的年龄分布差异无统计学意义(P=0.176),但筛查组中有41.4%(24/58)的患者年龄＞75岁,明显高于临床组(25.6%,P=0.0491).筛查组中血清PSA水平≥20.0 ng/ml的患者所占的比例为44.8%,明显低于临床组(75.6%,P＜0.0001).筛查组中活检Gleason评分＜7分的患者所占的比例为60.3%,明显高于临床组(34.1%,P=0.0020).筛查组中临床分期为T1和T2期(局限期)患者所占的比例为87.9%,明显高于临床组(26.8%,P＜0.0001).筛查组中接受根治性前列腺切除术的患者所占的比例为50.0%,明显高于临床组(18.3%,P＜0.0001).在年龄≤75岁的患者中,筛查组患者诊断时的血清PSA水平、活检Gleason评分和临床分期均显著低于临床组(均P＜0.05);在年龄＞75岁的患者中,筛查组患者的临床分期也明显低于临床组(P=0.0002),但两组诊断时血清PSA水平和活检Gleason评分的差异并无统计学意义(均P＞0.05).结论 应用血清PSA在我国50岁以上男性中进行前列腺筛查是有效的.筛查出的前列腺癌患者在血清PSA水平、活检Gleason评分、临床分期以及根治性切除的机会等方面均较临床组有明显优势.     

Pharmacokinetics of the green tea derivative, EGCG, by the topical route of administration in mouse and human skin

Purpose: (−)-Epigallocatechin gallate (EGCG), the main physiologically active polyphenol of green tea, is associated with antitumor and antimutagenic activities. The goal of this study was to determine the stability and pharmacokinetic parameters of pure EGCG administered topically to human and mouse skin. Methods: EGCG was investigated by measuring drug levels of a 10% ointment formulation stored under different conditions over a period of 6 months. To determine pharmacokinetic parameters of EGCG following topical application, EGCG was applied as 10% EGCG in hydrophilic ointment USP to full-thickness mouse or human skin in vitro. The transdermal and intradermal. Penetration of EGCG was measured by reverse phase HPLC assays at different time-points. Results: The stability of EGCG in hydrophilic ointment USP was dependent on time, temperature and the degree of oxidation. For example, 10% EGCG was lost after 2 days at 37 °C, but the same formulation supplemented with 0.1% butylated hydroxytoluene (BHT) had significantly longer stability with ≥90% EGCG remaining after 130 days at 37 °C. Topical application of EGCG in hydrophilic ointment USP to human or mouse skin resulted in substantial intradermal uptake of up to 1–20% of the applied dose. However, transdermal penetration was observed only in mouse skin. Conclusion: The present study showed that topical application of EGCG in hydrophilic ointment USP achieved high concentrations in skin but negligible systemic availability. The drug was susceptible to oxidation, but if supplemented with BHT, the hydrophilic ointment formulation could potentially be used in clinical trials of skin cancer prevention. Received: 9 February 1998 / Accepted 14 August 1998     

前列腺癌的质子治疗

质子具有独特的物理学特性,应用于前列腺癌的治疗,能够提高靶区的照射剂量,显著减少周围正常组织和器官的照射剂量,在照射剂量提高的同时并未增加直肠和膀胱的不良反应,可降低第二原发肿瘤的发生,改善前列腺癌的生存.