锌转运体1基因在脑胶质瘤组织中的表达及其对U87细胞增殖、迁移和 侵袭能力的影响

目的： 检测锌转运体1(zinc transporter 1,ZnT1)基因在胶质瘤组织中的表达,初步探索ZnT1对U87细胞增殖、迁移和 侵袭能力的影响。 方法： 收集2015年10月至2017年1月中国医科大学附属第一医院神经外科收治的术前未接受过放化疗的 Ⅱ～Ⅲ期胶质瘤患者20例,采用Real-time PCR和Western blotting检测胶质瘤组织与瘤旁组织中ZnT1 mRNA和蛋白的含量。向 胶质瘤细胞系U87中分别转染ZnT1和si-ZnT1质粒,构建ZnT1过表达和低表达细胞系,MTT和Transwell实验分别检测ZnT1对 U87细胞增殖、侵袭和迁移的影响。 结果： ZnT1 mRNA和蛋白在胶质瘤组织中表达显著高于瘤旁组织（均P<0.05）。成功构建 ZnT1过表达和低表达U87细胞系。与空白和空质粒对照组相比,转染12 h后,ZnT1过表达U87细胞的增殖（0.54±0.01 vs 0.45± 0.04、0.43±0.03,P<0.01）、侵袭和迁移能力（均P<0.05）显著升高;而转染12 h后ZnT1低表达U87细胞的增殖（0.37±0.03 vs 0.45±0.01、0.44±0.03,P<0.01）、侵袭和迁移能力（均P<0.05）显著降低。 结论： ZnT1在胶质瘤组织中呈高表达,ZnT1可以促进 胶质瘤U87细胞的增殖、迁移和侵袭。     

S100A6在胶质瘤组织中表达及对U87细胞增殖和侵袭力的影响

摘 要：［目的］ 探讨S100A6在胶质瘤组织中表达及对U87细胞增殖和侵袭力的影响。［方法］ 选取2017年3月至2019年3月在郑州大学第五附属医院择期行手术治疗的胶质瘤患者105例,利用实时荧光定量PCR技术检测胶质瘤和癌旁组织中S100A6基因表达,培养人胶质瘤U87细胞,根据转染物的不同将细胞分为siRNA-S100A6组、siRNA-对照序列组和空白对照组,利用实时荧光定量PCR技术和Western blot技术检测细胞中S100A6基因和蛋白表达,MTT法检测细胞增殖能力,划痕实验检测细胞迁移能力,Transwell小室检测细胞侵袭能力。［结果］ 胶质瘤组织中S100A6 mRNA相对表达量为1.95±0.16,癌旁组织中S100A6 mRNA相对表达量为1.33±0.13,两组差异有统计学意义（t=30.776,P<0.001）。与WHO分级Ⅰ～Ⅱ级相比,Ⅲ～Ⅳ级中S100A6mRNA表达量显著性升高（P<0.001）。与空白对照组和siRNA-对照序列组相比,siRNA-S100A6组细胞中S100A6 mRNA和蛋白表达量均降低（P均<0.001）,24h、48h、72h和96h细胞增殖活性被抑制（P<0.05）,划痕愈合率降低（P<0.001）,且侵袭细胞数显著性减少（P<0.001）。［结论］ S100A6在胶质瘤组织中呈高表达,且与胶质瘤恶性程度有关,特异性沉默U87细胞中S100A6基因表达可有效抑制细胞增殖,降低细胞迁移和侵袭能力。     

人脑胶质瘤组织高表达nNav1.5促进肿瘤细胞的迁移和侵袭

目的：观察电压-门控钠离子通道（voltage-gated sodium channel, VGSC）亚型nNav1.5在人脑胶质瘤组织中的表达,并探讨其对脑胶质瘤U251细胞迁移及侵袭的影响。方法：收集中国医科大学附属第一医院神经外科于2011年10月至2012年10月手术切除并经病理证实的脑胶质瘤组织标本68例,应用免疫组织化学S-P法检测脑胶质瘤组织中nNav1.5的表达。设计并化学合成nNav1.5基因特异性小干扰RNA（nNav1.5-siRNA）,用脂质体介导转染胶质瘤U251细胞,应用Real-time PCR和Western blotting法分别检测U251细胞中nNav1.5 mRNA和蛋白的表达水平,并采用细胞划痕实验和Transwell侵袭实验检测U251细胞迁移和侵袭能力的变化。结果：nNav1.5在人脑胶质瘤组织中表达的阳性率显著高于正常组织（72.6% vs 23.0%,P<0.01）,并且其在高级别胶质瘤（WHO Ⅲ～Ⅳ级）组织中的阳性率明显高于低级别胶质瘤（WHOⅠ～Ⅱ级）组织（85.8% vs 52.9%,P<0.01）。nNav1.5-siRNA转染可显著抑制U251细胞中nNav1.5 mRNA和蛋白的表达（P<0.01）;转染后U251细胞的迁移距离明显小于未转染细胞\[(0.019±0.015) vs（0.223±0.031）mm,P<0.01\],且其侵袭指数明显低于未转染细胞\[(2.99±0.15)% vs（6.77±0.26）%,P<0.01\]。〖JP2〗结论：nNav1.5在人脑胶质瘤组织中高表达,干扰nNav1.5表达可显著抑制胶质瘤细胞的迁移和侵袭能力,nNav1.5是胶质瘤恶性侵袭的调控因子并有望成为胶质瘤的新标志物和治疗靶点。     

miR-640通过抑制SLIT1介导Wnt/β-catenin通路促进脑胶质瘤对替莫唑胺的耐药

摘 要：［目的］评价miR-640介导Wnt/β-catenin通路对脑胶质瘤耐药细胞增殖、侵袭及替莫唑胺(temazolamide,TMZ)敏感性的影响。［方法］ 利用实时荧光定量聚合酶链反应（RT-qPCR）测定脑胶质瘤细胞内miR-640的表达。U87/TMZ细胞分为NC inhibitor组、 miR-640 inhibitor组和miR-640 inhibitor+si-SLIT1组。用不同浓度（15、30、60、120、240 、480和960 μmol/L）TMZ处理细胞,检测细胞对TMZ的耐药性;运用细胞计数试剂盒8（CCK-8）、Transwell实验检测U87/TMZ细胞增殖活力和侵袭力;用双荧光素酶报告基因实验验证miR-640与SLIT1的靶向关系。采用Western blot检测Wnt/β-Catenin信号通路相关蛋白表达水平。［结果］ miR-640在脑胶质瘤细胞中高表达,转染后miR-640 inhibitor组的miR-640表达水平、侵袭细胞数目（57±23 vs 153±31）、IC50值（131.61±8.97 vs 293.33±11.28）、增殖率（18.48±4.23 vs 43.84±8.94）均比NC inhibitor组低（P<0.05）。miR-640靶向调控SLIT1的表达,miR-640 inhibitor+si-SLIT1组β-catenin、c-myc、Cyclin D1蛋白表达水平均高于miR-640 inhibitor组（P<0.05）。［结论］miR-640通过SLIT1介导Wnt/β-catenin通路促进脑胶质瘤增殖、侵袭及对替莫唑胺的耐药性。     

敲低性别决定区Y-box蛋白5对胃癌细胞增殖、侵袭和上皮间质转化的影响

摘 要：［目的］ 探讨敲低性别决定区Y-box蛋白5（Sox-5）的表达水平及对胃癌细胞增殖、侵袭和上皮间质转化（EMT）的影响。［方法］ 实时荧光定量聚合酶链反应（qRT-PCR）检测胃癌细胞和正常人胃黏膜上皮细胞中Sox-5 mRNA的相对表达水平；sh-NC和sh-Sox-5质粒转染BGC823细胞，蛋白免疫印迹实验检测Sox-5蛋白表达水平；MTT实验、划痕实验和Transwell实验分别检测BGC823细胞增殖活性、迁移能力和侵袭能力；蛋白免疫印迹实验检测扭曲蛋白（Twist）、波形蛋白（Vimentin）、E-钙黏蛋白（E-cadherin）的表达。［结果］ 胃癌细胞中Sox-5 mRNA的相对表达水平高于正常人胃黏膜上皮细胞（P<0.01）；与转染sh-NC组相比，转染sh-Sox5质粒组中Sox-5蛋白的相对表达水平降低（1.120±0.142 vs 0.124±0.010，t=9.032，P<0.001）；与转染sh-NC组相比，转染sh-Sox-5组细胞增殖活性显著降低（1.32±0.10 vs 0.74±0.06，t=3.514，P=0.005），迁移率能力减弱（46.2%±4.7% vs 17.6%±2.5%，t=9.625，P<0.001），侵袭能力减弱（93.7±9.1 vs 113.7±6.5，t=3.103，P=0.036）；敲低Sox-5蛋白表达后Twist和Vimentin蛋白表达减弱，E-cadherin蛋白表达增强（P均<0.001）。［结论］ 敲低胃癌细胞中Sox-5的表达，可抑制胃癌细胞的增殖、迁移、侵袭和EMT。     

WP1130通过下调β-catenin增强鼻咽癌细胞化疗敏感性

摘 要：［目的］探讨WP1130与顺铂联合用药对鼻咽癌细胞增殖和转移的影响及其可能机制。［方法］ CCK-8法检测鼻咽癌顺铂敏感细胞系HNE1和顺铂耐药细胞系HNE1/DDP的顺铂药物半抑制浓度（IC50）,以及不同浓度WP1130对鼻咽癌细胞活力的影响;选取适当药物浓度处理细胞,两种鼻咽癌细胞系分别分为4组：空白对照组（DMSO）、DDP单药组（6 ?滋mol/L顺铂）、WP1130单药组（1.25 ?滋mol/L WP1130）以及DDP+WP1130联合用药组（6 ?滋mol/L顺铂+1.25 ?滋mol/L WP1130）。MTT法检测鼻咽癌细胞增殖能力;细胞划痕实验检测鼻咽癌细胞迁移能力;Transwell侵袭实验检测鼻咽癌细胞侵袭能力;RT-PCR和Western blot实验检测顺铂耐药HNE1/DDP与亲本HNE1鼻咽癌细胞中β-catenin的表达情况以及不同药物处理对β-catenin的表达的影响。［结果］ 耐药HNE1/DDP细胞比亲本HNE1细胞对顺铂的耐受性提高了近5.7倍（5.17±0.33 vs 29.44±2.62,P＜0.01）。β-catenin在HNE1/DDP细胞中的mRNA表达上调约3.4倍（1.00±0.26 vs 3.44±0.39,P＜0.01）。与空白对照组和单药组相比,顺铂+WP1130联合用药组细胞中β-catenin的表达显著下调（HNE1：1.00±0.06 vs 0.78±0.07 vs 0.32±0.05,P＜0.05;HNE1/DDP：1.01±0.05 vs 0.57±0.07 vs 0.39±0.07,P＜0.05）,顺铂+WP1130联合用药组细胞增殖、迁移和侵袭能力均显著下降（P均＜0.01）。［结论］ WP1130与顺铂联合用药可以通过下调β-catenin的表达增强顺铂对细胞增殖、迁移和侵袭的抑制作用,从而增强鼻咽癌细胞的化疗敏感性。     

miR-6775-3p在乳腺癌细胞中的表达及其对乳腺癌细胞生物学行为的影响

背景与目的：微小RNA（microRNA,miRNA）与肿瘤的发生、发展过程密切相关。探讨miR-6775-3p在乳腺癌细胞系中的表达及其对乳腺癌细胞生物学行为的影响。方法：通过实时荧光定量聚合酶链反应（real-time fluorescence quantitative polymerase chain reaction,RTFQ-PCR）检测4种乳腺癌细胞系MDA-MB-231、MDA-MB-453、MDA-MB-468和BT-549中miR-6775-3p的表达水平,选取miR-6775-3p表达水平最低的乳腺癌细胞系过表达miR-6775-3p后,采用细胞计数试剂盒（cell counting kit-8,CCK-8）法检测细胞的增殖情况,同时采用transwell迁移和侵袭实验分别检测细胞迁移和侵袭能力的变化。通过RTFQ-PCR和蛋白［质］印迹法（Western blot）检测miR-6775-3p过表达的乳腺癌细胞系中细胞周期蛋白依赖性蛋白激酶4（cyclin-dependent protein kinase 4,CDK4）和CDK6,以及侵袭转移标志物基质金属蛋白酶（matrix metalloproteinase,MMP）17和MMP24 mRNA以及蛋白的表达变化。结果：RTFQ-PCR结果显示,乳腺癌细胞系MDA-MB-453中miR-6775-3p的表达最低,在MDA-MB-453细胞中转染miR-6775-3p mimics后,miR-6775-3p的表达水平明显升高（P<0.001）。CCK-8实验结果显示,MDA-MB-453细胞过表达miR-6775-3p后,细胞的增殖能力明显降低（P<0.01）。Transwell迁移和侵袭实验结果显示,MDA-MB-453细胞过表达miR-6775-3p后,细胞的迁移（P<0.001）和侵袭能力（P<0.01）明显降低。RTFQ-PCR和Western blot实验结果显示,CDK4、CDK6及MMP17、MMP24的mRNA表达和蛋白水平均显著降低（P<0.01）。结论：miR-6775-3p可能抑制乳腺癌细胞的增殖、迁移和侵袭能力。     

粉防己碱通过NF-κB通路抑制肿瘤相关成纤维细胞分泌IL-8阻断肺腺癌细胞的侵袭转移

摘 要：［目的］ 研究粉防己碱（tetrandrine,Tet）通过调控肿瘤相关成纤维细胞（CAF）旁分泌因子的表达抑制肺腺癌细胞侵袭转移的作用效应,探讨NF-κB通路在Tet抑制CAF分泌IL-8促进肺腺癌细胞侵袭转移中的重要作用。［方法］ 采用条件培养基（CM）刺激胚肺成纤维细胞MRC5建立CAF模型,Western blot实验分析Tet作用前后NF-κB通路蛋白IKK、IκB和p65表达和磷酸化水平,ELISA实验检测Tet作用前后CAF分泌IL-8情况,以及Tet对CAF诱导肺腺癌细胞H1975侵袭转移的影响。抗体封闭培养基中游离的IL-8,分析CAF诱导H1975细胞侵袭转移能力的变化,验证IL-8是否Tet调控CAF旁分泌因子的表达抑制H1975细胞侵袭转移的关键因子。［结果］ Tet作用24h,CAF中NF-κB通路蛋白IKK、IκB和p65蛋白的磷酸化水平显著性下降;Tet组培养基上清液中IL-8含量为（151.7±24.8）pg/ml,显著性低于模型组的（384.7±39.5）pg/ml（P<0.001）;模型组诱导H1975细胞迁移的数量为141.7±21.5,Tet组为41.3±11.9（P<0.01）;模型组诱导H1975细胞侵袭的数量为129.7±25.1,Tet组为56.7±14.5（P<0.05）。模型组诱导H1975细胞迁移的数量为152.3±25.5,IL-8封闭（aIL-8）组为61.7±15.5（P<0.01）;模型组诱导H1975细胞侵袭的数量为136.3±14.5,aIL-8组为73.3±12.7（P<0.01）。［结论］ Tet具有抑制CAF诱导肺腺癌细胞侵袭转移的作用效应,其机制与抑制NF-κB通路的活性和CAF分泌IL-8有关。     

Rap1GAP对胃癌细胞侵袭、迁移及上皮细胞-间充质转化的作用

摘 要：［目的］ 分析Rap1GAP对胃癌细胞增殖、侵袭及迁移能力的影响。［方法］ 运用qRT-PCR及Western blo法检测Rap1GAP在胃癌细胞中的表达。Rap1GAP载体慢病毒感染MGC803及MKN-45两个细胞系,构建出Rap1GAP高表达胃癌细胞系。MTT、细胞克隆形成实验、Transwell实验及划痕实验检测Rap1GAP 对胃癌细胞增殖、侵袭及迁移能力的影响。运用qRT-PCR及Western blot法检测上皮化标志物E-cadherin、Snail和N-cadherin的表达。［结果］正常细胞株GES-1中Rap1GAP表达量为1.02±0.08,而SGC7901、AGS、MGC803、HGC-27、MKN-45中表达量分别为0.66±0.10、0.51±0.10、0.20±0.08、0.31±0.07、0.26±0.11（P均<0.01）。体外实验显示Rap1GAP能抑制胃癌细胞的增殖（酶标仪检测波长为570 nm时的吸光度）、侵袭及迁移能力;且Rap1GAP能抑制胃癌细胞的EMT。［结论］ Rap1GAP在胃癌进展中起到抑癌作用,具有成为胃癌治疗靶点的潜力。     

长链非编码RNA linc01376调控鼻咽癌肿瘤进展机制分析

摘 要：［目的］ 探讨linc01376在鼻咽癌组织与细胞内的表达特征,分析其可能的调控机制。 ［方法］ 采用实时荧光定量（qT-PCR）方法检测鼻咽癌组织和细胞中linc01376表达水平;采用CCK-8法、克隆平板形成实验、流式细胞学检测、划痕实验、Transwell侵袭实验等检测细胞增殖、迁移和侵袭能力变化;通过Western blot实验测定分子蛋白水平,探索linc01376的下游调控机制。［结果］ qT-PCR结果表明,linc01376在鼻咽癌组织中表达明显高于正常鼻咽组织(20.230±1.815 vs 1.281±0.454,P<0.01)。linc01376表达越高,患者分期越晚（χ2=7.670,P<0.05）,肿瘤负荷越大(χ2=6.312,P<0.05)。细胞功能学实验显示与对照组相比,沉默linc01376明显抑制鼻咽癌细胞的增殖(5-8F：2.248±0.055 vs 1.790±0.041,t=6.675,P<0.01;CNE2：1.502±0.046 vs 1.012±0.068,t=5.994,P<0.01)、迁移和侵袭能力（5-8F：182.00±8.60 vs 92.67±6.24,t=11.89,P<0.01;CNE2：166.67±8.18 vs 90.67±3.68,t=11.98,P<0.01）。机制研究发现linc01376可通过影响miR-4757调控下游IGF1的表达,最终激活AKT/p-AKT信号通路发挥促进肿瘤进程作用。［结论］ linc01376在鼻咽癌进展中发挥重要调控作用,可能成为鼻咽癌靶向治疗的新靶点。     

E-钙粘蛋白及PTEN基因编码蛋白与胃癌浸润转移

目的:观察抑癌基因PTEN蛋白和ECD在胃癌组织中的表达,探讨其与胃癌生物学行为及预后的关系。方法:以兔抗人PTEN多克隆抗体、鼠抗人ECD单克隆抗体,采用SABC免疫组化法,检测100例胃癌手术切除标本中拟测指标的表达。以χ2和Logrank检验对结果做统计学分析。结果:ECD、PTEN蛋白在非癌胃粘膜中均见表达;在胃癌组织中表达下调或缺失。ECD异常表达率为42.0%;弥漫型胃癌异常表达率(48.57%),明显高于肠型胃癌(26.67%),(P<0.05);ECD异常表达与浸润深度有关(P<0.05)。胃癌组织中PTEN蛋白缺失率为59%;弥漫型胃癌缺失率(65.71%)明显高于肠型胃癌(43.33%),(P<0.05);伴淋巴结转移的胃癌缺失率(64.47%)明显高于无淋巴结转移者(41.67%),(P<0.05);PTEN蛋白缺失的患者比阳性表达者预后差(P=0.0066)。65.85%PTEN阳性表达者同时伴ECD正常表达。结论:两种标志物与胃癌浸润转移有关,PTEN表达与胃癌患者预后密切相关。将两种指标联合检测,可作为正确判断胃癌患者预后,指导临床治疗的分子生物学指标。     

Cytologic classification of precancer and cancer of the endometrium and esophagus and of malignant lymphomas

The paper discusses cytological classifications of precancer and cancer of the endometrium, esophagus and malignant lymphomas presented by cytologists from five Soviet research institutes of oncology. The classifications were based on the data of 4400 cases in conformity with WHO histologic classifications.     

世界卫生组织骨质疏松症防治工作报告和防治建议

引 言 作为对第51号综合处理非传染性疾病预防与控制的世界卫生组织决议的反应,1998年7月WHO成立了致力于不断完善对骨质疏松预防和治疗策略的工作小组。小组成员来自世界各国致力于骨质疏松研究的知名专家。Harry K.Genant为本届主席。这一项世界范围内的骨质疏松教育计划旨在通过世界范围的研究,不断改善对骨质疏松的诊断水平和发展并完善对骨质疏松病人的合理治疗。其重点将以发展中国家为主。并为各国政府及其卫生部门和病人群体提供世界性有关骨质疏松症的总体的、完整的指导性资料。该项研究、教育计划的实施将由世界各国的骨质疏松症研究和治疗机构共同完成,并经权威学术机构、政府和非政府组织进行有针对性的回顾研究,最终由WHO审议通过。     

Schwannomas of Head and Neck and Review of Literature

Benign nerve cell tumours have been given various names like schwannoma, neurilemmoma, neurinoma, neurofibroma, spindle cell tumours etc. Extra cranial head and neck schwannomas usually present as solitary and well-demarcated lesions. The lesion can cause secondary symptoms, such as nasal obstruction, dysphasia, and hoarseness, depending upon the location of the lesion. Fine needle aspiration cytology, CT scans, and MRI may be of limited help in the diagnosis of schwannomas. The treatment is complete surgical excision of the benign tumour and postoperative histopathological examination establishes the final diagnosis.     

Quality of life and care in leukemia,myeloma and non-malignant disease. Opinions of patients and relatives,and effects of geography and time

In a questionnaire study 140 subjects answered 4200 questions in 1980 and 1986. They consisted of patients with myeloma, acute leukemia, lung carcinoma, and non-malignant disease and their relatives. In 22 additional cases the questionnaire was not answered. The results show that myeloma patients are less content with the general care than leukemia patients (P < 0.05). Similarly, relatives of deceased myeloma patients are less satisfied with the information given to them than relatives of deceased leukemia patients (P < 0.001). The information has improved with time, however, since the patients were more satisfied in 1986 than in 1980 (P < 0.001) and relatives of myeloma patients still alive were more satisfied than relatives of patients who had died earlier (P < 0.001).     

A comparative study of knowledge and awareness of colorectal and breast cancerA comparative study of knowledge and awareness of colorectal and breast cancer

Aims: To assess and compare knowledge and awareness of colorectal cancer and breast cancer in a sample of the general population. Methods: Eleven hundred visitors to six different outpatient clinics, in a University Hospital, were given a study-specific questionnaire, based on educational material from the British Association of Cancer United Patients (CancerBACUP). The questionnaire consisted of 12 statements on the incidence, presentation, detection, treatment and prognosis of colorectal and breast cancer. Results: One thousand and sixty-eight individuals returned the questionnaire. One thousand and four completed questionnaires were analysed. The mean age (SD) of respondents was 50.1 (17.2) years, and the male to female ratio was 2:3. Respondents had read more about breast than about colorectal cancer (60.3%vs 32.4%,P <0.0001, McNemar's test). The proportion of correct answers for each statement on breast cancer was higher than for answers to corresponding items on colorectal cancer. Mean overall scores (95% CI) for breast and colorectal cancer were 88.1 (86.9, 89.2) and 64.4 (62.5, 66.3) respectively, the mean difference (95% CI) being 23.7 (22.0, 25.5). Scores were higher for breast cancer irrespective of age or gender. Conclusion: There is a low level of understanding of colorectal cancer in the general population when compared to breast cancer. This highlights the importance of public education in this common cancer.     

Prospective study of fruit and vegetable consumption and incidence of colon and rectal cancers

BACKGROUND: Frequent consumption of fruit and vegetables has been associated with a reduced risk of colorectal cancer in many observational studies. METHODS: We prospectively investigated the association between fruit and vegetable consumption and the incidence of colon and rectal cancers in two large cohorts: the Nurses' Health Study (88 764 women) and the Health Professionals' Follow-up Study (47 325 men). Diet was assessed and cumulatively updated in 1980, 1984, 1986, and 1990 among women and in 1986 and 1990 among men. The incidence of cancer of the colon and rectum was ascertained up to June or January of 1996, respectively. Relative risk (RR) estimates were calculated with the use of pooled logistic regression models accounting for various potential confounders. All statistical tests were two-sided. RESULTS: With a follow-up including 1 743 645 person-years and 937 cases of colon cancer, we found little association of colon cancer incidence with fruit and vegetable consumption. For women and men combined, a difference in fruit and vegetable consumption of one additional serving per day was associated with a covariate-adjusted RR of 1.02 (95% confidence interval [CI] = 0.98-1.05). A difference in vegetable consumption of one additional serving per day was associated with an RR of 1.03 (95% CI = 0.97-1.09). Similar results were obtained for women and men considered separately. A difference in fruit consumption of one additional serving per day was associated with a covariate-adjusted RR for colon cancer of 0.96 (95% CI = 0.89-1.03) among women and 1. 08 (95% CI = 1.00-1.16) among men. For rectal cancer (total, 244 cases), a difference in fruit and vegetable consumption of one additional serving per day was associated with an RR of 1.02 (95% CI = 0.95-1.09) in men and women combined. None of these associations was modified by vitamin supplement use or smoking habits. CONCLUSIONS: Although fruits and vegetables may confer protection against some chronic diseases, their frequent consumption does not appear to confer protection from colon or rectal cancer.