RGD肽在肿瘤显像和治疗中的应用研究进展

介绍精氨酸（Arg）—甘氨酸（Gly）—天冬氨酸（Asp）肽（RGD肽）在肿瘤诊治领域应用研究新进展．内源性RGD肽存在于多种生物细胞外基质中，参与多条信号传导通路的活化，在多种生理和病理过程中发挥重要作用。外源性RGD肽与肿瘤细胞表面整合素结合后，可作为体内RGD肽类物质的竞争性抑制剂，从而能抑制肿瘤细胞与细胞外基质的黏附与迁移、抑制肿瘤血管形成、诱导肿瘤细胞凋亡。RGD肽能与肿瘤高表达的整合素受体结合，并从多个环节对肿瘤起到抑制作用，其具有靶向性进行肿瘤显像及肿瘤治疗的潜在应用价值。     

人脂联素重组体体外对乳腺癌细胞侵袭和转移的抑制

目的：研究人脂联素重组体对人乳腺癌MDA—MB-231细胞体外侵袭能力的影响。方法：将MDA—MB-231细胞分设对照组和脂联素重组体加药（2．5、5、0、10、20、30μg／ml）组，药物作用一定时间后，分别以MTT法、Transwell小室实验，Chamber小室实验，黏附实验检测脂联素重组体对乳腺癌细胞增殖、侵袭、迁移和黏附能力的影响，以明胶酶谱法检测其对肿瘤细胞分泌MMP-2和MMP-9的影响。结果：脂联素重组体质量浓度高于5．0μg／ml时，对MDA—MB-231细胞生长具有明显的抑制作用（P〈0．01）；能明显地降低肿瘤细胞体外侵袭能力（P〈0．01），侵袭抑制率随脂联素重组体质量浓度的升高而增加，介于22．64％～77．84％之间；脂联素重组体质量浓度高于2．5μg／ml时，明显地抑制肿瘤细胞的迁移能力（P〈0．01）；脂联素重组体对ECM和FN黏附能力影响的程度不同，对FN的敏感性大于ECM；脂联素重组体质量浓度大于2．5μg／ml时，明显抑制肿瘤细胞MMP-2和MMP-9的分泌（P〈0、05或P〈0．01），后者的分泌量随质量浓度的升高而下降。结论：脂联素重组体在大于2．5μg／ml时，可能通过保护基底膜不受破坏而抑制人乳腺癌细胞的侵袭能力。     

Survivin反义寡核苷酸诱导SMMC-7721细胞凋亡及对化疗药物敏感性作用的研究

目的：观察survivin反义寡核苷酸（ASODN）对SMMC-7721细胞增殖、凋亡的影响及其对化疗药物敏感性的作用。方法：设计合成特异性survivin的ASODN，脂质体转染肝细胞癌SMMC-7721细胞，透射电镜观察细胞超微结构变化；RT—PCR法检测survivinmRNA的表达变化；FCM法检测对细胞周期、凋亡及survivin蛋白表达的影响；MTT法测定survivin表达抑制前后细胞对吡柔比星、氟苷、顺铂敏感性的影响。结果：ASODN转染后细胞呈现凋亡的形态学改变，survivin mRNA和蛋白表达减弱（P〈0．05），诱导SMMC-7721细胞凋亡（P〈0．01），细胞周期阻滞于G2／M期（P〈0．05）。ASODN转染组可增加SMMC-7721细胞对吡柔比星、氟苷、顺铂的敏感性（P〈0、01）。结论：Survivin ASODN转染能下调survivin表达，诱导SMMC-7721细胞凋亡，提高对吡柔比星、氟苷、顺铂的敏感性。     

多西紫杉醇诱导SMMC-7721肝癌细胞凋亡中的氧化——抗氧化失衡研究

[目的]探讨多西紫杉醇在诱导肝癌SMMC-7721细胞凋亡过程中细胞氧化应激以及氧化－抗氧化失衡情况。[方法]取体外培养的对数生长期SMMC-7721细胞，并将培养细胞暴露于10^-8mol／L多西紫杉醇，24h后在荧光显微镜下检测细胞凋亡形态，并利用流式细胞仪测定细胞内活性氧（reactive oxygen species，ROS）以及谷胱甘肽（glutathion，GSH）水平。[结果]SMMC-7721细胞暴露于10^-8mol／L多西紫杉醇24h后发生凋亡，细胞内活性氧为68．43％±10.47％，显著高于对照组20.32％±3．52％（P〈0．001）。细胞内GSH水平4．5±1．2fmol／cell，显著低于对照组11．5＋2．5fmol／cell（P〈0．05）。[结论]多西紫杉醇诱导细胞凋亡过程中存在氧化应急以及氧化一抗氧化失衡，ROS可能参与了细胞凋亡的过程。     

β肽及其多聚物对人肝癌细胞株与基质黏附的抑制作用

目的研究β肽及其多聚物对肝癌细胞株与基质黏附的抑制作用.方法观察化学合成的β肽（β肽）、化学合成的二聚β肽（β2肽）、化学合成的三聚β肽（β3肽）、用大肠杆菌表达系统表达的表达β3肽及GRGDS对人肝癌细胞株SMMC-7721细胞及人肝癌高转移细胞株HCCLM6细胞与纤连蛋白（fibronectin,FN）的黏附作用的影响.结果各种多肽对细胞与FN的黏附均具有特异的抑制作用,呈现剂量效应相关关系和时间效应相关关系（P〈0.05）.且随着多肽重复次数的增多,对细胞与FN黏附的抑制作用越强,表达β3肽和β3肽的抑制肿瘤细胞黏附的作用最强,β2肽和GRGDS的作用次之,β肽的抑制作用最弱.各种多肽对HCCLM6细胞与FN黏附的抑制作用强于对SMMC-7721细胞的黏附抑制作用.结论表达β3肽对肝癌细胞株与基质的黏附具有强大的抑制作用,可能成为抗肿瘤转移的新的药物手段.     

槲寄生碱抑制肺癌细胞增殖作用初步观察

目的：研究槲寄生碱对人肺腺癌细胞株SPC-A1及肺鳞癌细胞株SK—MES-1的抑制作用。方法：采用四甲基噻唑氮蓝（methy lthiazolyl tetrazolium,MTT）比色法检测不同浓度槲寄生碱作用24和48h对细胞增殖的影响,以含不同浓度的5-氟尿嘧啶（5-FU）细胞组为阳性对照,不舍药物的细胞组为阴性对照,计算半数抑制浓度（IC50）。流式细胞术（flow cytometry,FCM）检测高、中和低3组浓度的槲寄生碱作用24h后的细胞的凋亡率。结果：不同浓度槲寄生碱作用24h,对SPC-A1细胞的IC50为（14．43±0．53）／μg／mL,对SK—MES-1细胞的IC50为（8．09±0．40）μg／mL。其作用48h,对SPC—A1细胞的IC50为（12．11±0．25）μg／mL,对SK—MES-1细胞的ICs0为（6．43±0．33）μg／mL。并且抑制作用随碱浓度的升高和作用时间的延长而增加,P〈0．05。阳性对照组5-FU作用24h,对SPC-A1细胞的IC50为（4．79±0．45）〉g／mL,对SK—MES-1细胞的IC50为（5．15士0．23）μg／mL。作用48h,对SPC—A1细胞的IC50为（4．35±0．41）μg／mL,对SK—MES-1细胞的IC50为（4．11±0．38）／lg／mL。FCM检测SPc_A1细胞未加入药物的对照组凋亡率为（0．43±0．01）％,高剂量组药物浓度28．86μg／mL,凋亡率为（31．09±0．05）%,中剂量组药物浓度14．43〉g／mL,凋亡率为（18．19士0．02）％,低剂量组药物浓度7．22μg／mL,凋亡率为（7．99±0．01）％。SK—MES-1细胞未加入药物的对照组凋亡率为（O．57士0．02）％,高剂量组药物浓度16．18ug／mL,凋亡率为（38．24±0．03）％,中剂量组药物浓度为8．09μg／mL,凋亡率为（21．81±0．01）%,低剂量组药物浓度4．05μg／mL,凋亡率为（9．11±0．01）％,与没有加入槲寄生碱的细胞相比,加入槲寄生碱后SPC—A1细胞与SK—MES-1细胞凋亡率均明显增加,P〈0．05,并且凋亡率随槲寄生碱剂量的增加而升高,P〈0．05。结论：槲寄生碱能够抑制人肺腺癌细胞株SPC-A1及肺鳞癌细胞株SK-MES-1的增殖,并能促进细胞的凋亡,为槲寄生碱应用于肺癌的临床治疗提供了实验依据。     

沙利度胺对人肝癌细胞株SMMC-7721体外生长的抑制作用

目的 研究沙利度胺对人肝癌细胞株SMMC-7721体外生长的抑制作用及其可能的机制.方法 将不同浓度的沙利度胺作用于人肝癌细胞株SMMC-7721,采用四甲摹偶氮唑蓝(MTT)法检测沙利度胺对SMMC-7721细胞的增殖抑制作用.将SMMC-7721细胞培养至对数生长期,采用DNA琼脂糖凝胶电泳、荧光显微镜观察、流式细胞仪检测等方法 观察沙利度胺处理后SMMC-7721细胞的凋亡梯度、形态学变化和凋亡率,并对凋亡调控蛋白caspase-3的表达进行测定.采用酶联免疫吸附(ELISA)法测定不同浓度的沙利度胺处理后SMMC-7721细胞表达血管内皮生长因子(VEGF)的变化.结果 沙利度胺的浓度从3.125μg/ml增至200μg/ml时,其对SMMC-7721细胞的增殖抑制率从11.7%增至34.2%;当沙利度胺的浓度>25 μg/ml时,其对SMMC-7721细胞的增殖抑制作用明显强于空白对照组(P<0.05).200 μg/ml的沙利度胺处理SMMC-7721细胞24 h后,行琼脂糖凝胶电泳,可见到DNA梯形条带;48 h后梯形条带更明显,并且在荧光显微镜下可见SMMC-7721细胞出现核固缩和核裂解现象.200μg/ml的沙利度胺处理SMMC-7721细胞12、24、48和72 h时,碘化丙啶(PI)法检测SMMC-7721细胞的凋亡率分别为3.1%±0.5%、8.4%±1.3%、19.4%±3.5%和25.8%±2.1%,24 h起的凋亡率均明显高于空白对照组SMMC-7721细胞48 h的自然凋亡率(1.6%±0.6%,均P<0.05).50、100和200μg/ml的沙利度胺处理SMMC-7721细胞48 h时,Annexin V-FITC/PI双标法检测SMMC-7721细胞的凋亡率分别为8.7%±1.2%、16.8%±2.5%和25.4%±4.5%,均明显高于空白对照组SMMC-7721细胞48 h的自然凋亡率(2.1%±0.5%,均P<0.05).随着沙利度胺浓度的增加,表达caspase-3蛋白的SMMC-7721细胞数量不断增加,而SMMC-7721细胞中VEGF的含量却逐渐下降.结论 沙利度胺可能通过诱导肝癌细胞的凋亡、抑制肿瘤血管的生成而发挥双重抗肿瘤生长的作用.     

Survivin与Caspase-3在光动力诱导肝癌细胞SMMC-7721凋亡中的作用

目的：探讨Survivin与Caspase-3在血卟啉化衍生物（hematoporphyrin derivative,HPD）光动力作用（photodynamic therapy,PDT）诱导人肝癌细胞SMMC-7721凋亡中作用。方法：应用流式细胞术检测光动力作用后细胞凋亡率。用免疫组化法检测细胞内Survivin及Caspase-3蛋白表达情况,并用RT—PCR检测其基因水平。结果：血卟啉衍生物光动力组人肝癌细胞SMMC-7721凋亡率达（33．42±5．52）％,与对照组相比,差异有显著意义（P〈0．05）;光动力作用后Survivin的蛋白表达及基因水平显著低于对照组（P〈0．05）,而Caspase-3却显著高于对照组（P〈0．05）。结论：血卟啉衍生物光动力作用具有诱导人肝癌细胞SMMC7721凋亡的生物学效应,其作用机制可能与光动力作用抑制凋亡调控蛋白Survivin表达,并且直接或间接促进Caspase-3的表达,从而促进细胞凋亡。     

阿霉素联合TRAIL对人肝癌细胞增殖与TRAIL受体表达的影响

目的 探讨阿霉素联合肿瘤坏死因子相关凋亡诱导配体（TRAIL）对肝癌细胞HepG2和SMMC-7721增殖及TRAIL受体表达的影响。方法 采用MTT法分别检测阿霉素、TRAIL及低浓度阿霉素联合TRAIL处理HepG2和SMMC-7721细胞的生长抑制率;RT-PCR和Western blotting分别检测阿霉素作用前后HepG2和SMMC-7721细胞TRAIL受体DR4、DR5的mRNA和蛋白表达水平。结果 3种浓度阿霉素（0.86、8.6、86μmol／L）作用24h后,对HepG2和SMMC-7721细胞的生长抑制率分别为（8.84±0.44）％和（8.67±1.22）％、（24.12±1.11）％和（25.39±2.26）％、（64.55±4.05）％和（66.2±3.74）％,呈浓度依赖性,不同浓度组之间差异均有统计学意义（P＜0.05）。4种浓度TRAIL（10、100、500、1000ng／ml）作用24h后,对HepG2和SMMC 7721细胞的生长抑制率分别为（5.83±0.25）％和（5.66±0.56）％、（9.60±1.38）％和（8.96±1.13）％、（11.87±1.43）％和（12.11±1.84）％、（15.12±3.84）％和（16.16±1.41）％,其他3种浓度分别与10ng／ml TRAIL比较,差异均有统计学意义（P＜0.01）。低浓度阿霉素联合TRAIL作用于HepG2和SMMC-7721细胞,低浓度阿霉素能够增加HepG2和SMMC-7721细胞对TRAIL治疗的敏感性,并且随着时间的延长和TRAIL浓度的增加,细胞抑制率逐渐增加,呈时间 效应和剂量 效应关系;无论在mRNA还是蛋白水平,阿霉素处理后HepG2细胞死亡受体DR4、DR5的表达水平较未处理组显著增加;在SMMC-7721细胞,阿霉素处理后,DR5的表达水平显著增加,而DR4的表达水平与阿霉素未处理组相似。结论 低浓度阿霉素能够增加肝癌细胞对TRAIL治疗的敏感性,其机制可能是阿霉素增加死亡受体特别是DR5的表达水平,从而诱导细胞凋亡增加,TRAIL在肝癌治疗方面存在潜在的临床应用价值。     

重组人IL-24蛋白诱导肝癌细胞生长抑制和凋亡

目的研究重组人IL-24蛋白（rhIL-24）选择性诱导肝癌细胞生长抑制和凋亡的作用。方法重组由Igk前导肽、IL-24cDNA（不含自身信号肽）和myc—tag组成的融合基因（Igk7m），构建表达载体pcDNA3．1-Igk7m，稳定转染293细胞，表达并粗提分泌性rhIL-24蛋白。以人肝癌细胞株PLC／PRF／5（p53突变型）、SMMC-7721（p53野生型）和正常人肝细胞株WRL-68为靶细胞，用活细胞计数法和TUNEL法分析rhIL-24处理对培养的靶细胞生长和凋亡的影响。结果经测序鉴定，融合基因各片段的核苷酸序列和总阅读框架完全正确。应用Westernblot在筛选的转基因293细胞克隆和其培养上清中均检测到rhIL-24蛋白，分子量分别约为25kDa和35kDa。与WRL-68对照组相比，分泌性rhIL-24蛋白粗提液处理可显著抑制PLC／PRF／5和SMMC-7721肝癌细胞的生长增殖（P〈0．01）。rhIL-24蛋白处理还可显著增加PLC／PRF／5和SMMC-7721的凋亡细胞百分率（P〈0．01），而对正常肝细胞WRL-68无明显影响（P〉0．05）。结论rhIL-24蛋白能选择性诱导培养的肝癌细胞株PLC／PRF／5和SMMC-7721生长抑制和凋亡。     

Tobacco, alcohol, diet, occupation, and carcinoma of the esophagus

Information on occupation, smoking, food and beverage consumption, and medical history were compared between 275 incident cases of carcinoma of the esophagus and 275 neighborhood controls who were matched to the cases on age (within 5 years), race, and sex. Tobacco use, mainly cigarette smoking, was a significant risk factor for carcinoma of the esophagus. Ex-smokers of cigarettes showed a reduced risk relative to those who continued to smoke, and current smokers of two or more packs per day displayed a higher risk than those who smoked less. Alcohol consumption was another significant risk factor for carcinoma of the esophagus; there was a highly significant trend with average daily dose of ethanol. Relative to controls, cases also consumed significantly more fried bacon or ham, less fresh fruits and raw vegetables, and were more likely to prefer white than whole grain bread. Finally, there was a significant association between carcinoma of the esophagus and long-term occupational exposure to metal dust; this association was largely confined to the lower one-third section of the esophagus.     

Age,Race, Sex,Stage, and Incidence of Cutaneous Lymphoma

BackgroundThe incidence of the T- and B-cell CLs has been well documented, but information pertaining to racial incidence by age, and by burden of disease (stage) have not been extensively documented.Materials and MethodsThe SEER 2004-2008 public use database was investigated. The relative incidence of CL in different races and age groups was examined. Univariate and multivariate stepwise logistic regression was performed for the likelihood of presenting at a higher stage.ResultsOf 4496 patients diagnosed with CL between 2004 and 2008; 1713 patients were diagnosed with MF, 1518 with non-MF cutaneous T-cell lymphoma, and 1265 patients with cutaneous B-cell lymphoma. For MF, there was a trend for females to be less likely to present with a higher T-stage (T3-T4) than males (odds ratio [OR], 0.73) on multivariate analysis (P = .06). For race, AA had a significantly increased risk of presenting with higher T-stage (T3-T4) MF (OR, 1.72) on multivariate analysis (P = .02), compared with white patients. For white, AA, Asian/Pacific Islander, and Native American/other/unknown, the mean age at diagnosis was 59.2, 51.5, 51.3, and 53.8. These groups presented at a significantly different age than white (P = .0001, 0.0001, and 0.0006).ConclusionNonwhite racial groups present with MF at an earlier age compared with white, and AA have increased risk of presenting with higher T-stage compared with white. These findings have significant implications regarding need for earlier diagnosis and understanding the reasons for racial disparity in age and stage of presentation.     

Susceptibility of Ureaplasma urealyticum to Tetracycline,Doxycycline, Erythromycin,Roxithromycin, Clarithromycin,Azithromycin, Levofloxacin and Moxifloxacin

Abstract

The in vitro activity of tetracycline, doxycycline, erythromycin, roxithromycin, clarithromycin, azithromycin, levofloxacin and moxifloxacin was tested against 63 clinical isolates of Ureaplasma urealyticum. The minimal inhibitory concentrations (MICs) and the minimal bactericidal concentrations (MBCs) were determined by the broth microdilution method in A7 medium. The miC50 and miC90 of the tested agents after 24 h of incubation were as follows: Tetracycline, 0.5 and 2.0 μg/ml; doxycycline, 0.125 and 0.25 μg/ml; erythromycin, 2.0 and 8.0 μg/ml; roxithromycin, 2.0 and 4.0 μg/ml; clarithromycin, 0.25 and 1.0 μg/ml; azithromycin, 2.0 and 4.0 μg/ml; levofloxacin, 1.0 and 2.0 μg/ml; and moxifloxacin, 0.5 and 0.5 μg/ml, respectively. The MIC values after 24 h and 48 h incubation differed by no more than one dilution for all the agents with the exception of doxycycline (two dilution difference for MIC₉₀). Overall, moxifloxacin was the most active agent in vitro against U. Urealyticum, with the narrowest difference between MIC and MBC values, followed closely by levofloxacin. Clarithromycin was the most active macrolide.     

Fat, fiber, fruits, vegetables, and risk of colorectal adenomas

A case-control study was conducted at the National Naval Medical Center (Maryland, USA) from 1994 to 1996 to investigate the possible association between dietary factors and colorectal adenomas. Cases (n = 239) were subjects diagnosed with adenomas (146 new and 93 recurrent) by sigmoidoscopy or colonoscopy. Those with no evidence of adenomas found by sigmoidoscopy were recruited as controls (n = 228). Dietary variables, assessed by a 100-item food frequency questionnaire, were analyzed by the logistic regression model, which was adjusted for age, gender and total energy intake. Variables of fat intake were further adjusted for red meat intake. An increased risk of 7% [odds ratio (OR): 1.07; 95% confidence interval (95% CI): 0.94-1.22] per 5% energy/day from total fat was observed. Every additional 5% unit of oleic acid intake/day significantly increased the adenoma risk by 115% (OR: 2.15; 95% CI: 1.05-4.39). Red meat fat increased the risk by 20% (OR: 1.20; 95% CI: 0.71-2.04), and white meat fat decreased the risk by 67% (OR: 0.33; 95% CI: 0.19-0.95) for every additional 5% unit of respective intake/day. Risk decreased by 41% (OR: 0.59; 95% CI: 0.41-0.86) for every additional 5% unit of fiber intake/day. Vegetable [OR per 100 g of vegetable intake/day: 0.83, 95% CI: 0.67-1.04] and fruit (OR per 100 g of fruit intake/day: 0.92, 95% CI: 0.82-1.03) intake showed an inverse association, and the results are suggestive of an association with the risk for adenomas. In conclusion, a strong positive association between oleic acid intake and colorectal adenoma risk was observed. This is likely to be an indicator of "unhealthy" food (meat, dairy, margarine, mayonnaise, sweet baked food) consumption in this population. Increased intake of dietary fiber was associated with a moderately decreased risk of adenomas.     

Susceptibility of Ureaplasma urealyticum to tetracycline, doxycycline, erythromycin, roxithromycin, clarithromycin, azithromycin, levofloxacin and moxifloxacin

The in vitro activity of tetracycline, doxycycline, erythromycin, roxithromycin, clarithromycin, azithromycin, levofloxacin and moxifloxacin was tested against 63 clinical isolates of Ureaplasma urealyticum. The minimal inhibitory concentrations (MICs) and the minimal bactericidal concentrations (MBCs) were determined by the broth microdilution method in A7 medium. The MIC(50) and MIC(90) of the tested agents after 24 h of incubation were as follows: tetracycline, 0.5 and 2.0 μg/ml; doxycycline, 0.125 and 0.25 μg/ml; erythromycin, 2.0 and 8.0 μg/ml; roxithromycin, 2.0 and 4.0 μg/ml; clarithromycin, 0.25 and 1.0 μg/ml; azithromycin, 2.0 and 4.0 μg/ml; levofloxacin, 1.0 and 2.0 μg/ml; and moxifloxacin, 0.5 and 0.5 μg/ml, respectively. The MIC values after 24 h and 48 h incubation differed by no more than one dilution for all the agents with the exception of doxycycline (two dilution difference for MIC(90)). Overall, moxifloxacin was the most active agent in vitro against U. urealyticum, with the narrowest difference between MIC and MBC values, followed closely by levofloxacin. Clarithromycin was the most active macrolide.     

Occurrence,Efficacy, Metabolism,and Toxicity of Triclosan

Triclosan has broad-spectrum anti-microbial activity against most gram-negative and gram-positive bacteria. It is widely used in personal care products, household items, medical devices, and clinical settings. Due to its extensive use, there is potential for humans in all age groups to receive life-time exposures to triclosan, and, indeed, triclosan has been detected in human tissues and the environment. Data gaps exist regarding the chronic dermal toxicity and carcinogenicity of triclosan, which is needed for the risk assessment of triclosan. The US Food and Drug Administration (FDA) nominated triclosan to the National Toxicology Program (NTP) for toxicological evaluations. Currently, the NTP is conducting several dermal toxicological studies to determine the carcinogenic potential of triclosan, evaluate its endocrine and developmental-reproductive effects, and investigate the potential UV-induced dermal formation of chlorinated phenols and dioxins of triclosan. This paper reviews data on the human exposure, environmental fate, efficacy of anti-microbial activity, absorption, distribution, metabolism and elimination, endocrine disrupting effects, and toxicity of triclosan.     

Histologic features of bladder cancer in Boston,USA, Manchester,UK, and Nagoya,Japan

Histologic characteristics of bladder cancer in Boston, USA, Manchester, UK, and Nagoya, Japan, were evaluated. In each of these areas broadly-based series of cases were assembled during a collaborative case-control study. The present analysis was based on 589 cases in Boston, 484 cases in Manchester, and 241 cases in Nagoya. A single pathologist reviewed a slide of the primary tumor without reference to identifying information or other data. The primary histologic type of nearly all tumors was transitional-cell, and there was little variation in the proportion of transitional-cell tumors among the study areas. Nor was there much variation in the distribution of histologic grade, the proportion of tumors showing submucosal invasion, or the proportion of tumors with a papillary surface. Age at diagnosis was strongly correlated with histologic grade. The proportion of grade III (most malignant) tumors was about twice as high among patients 80 years of age and over as among those aged less than 50. An apparent association between age and submucosal invasion was explained in large part by the relationships of histologic grade to submucosal invasion and to age. Other histologic features had only weak and inconsistent relations with age. None of the features evaluated showed consistent associations with history of cigarettesmoking or with sex.