炎症与癌症的关系已逐渐成为关注热点,也是当前癌症研究领域的共识。可是,对于炎症是如何诱发癌症的问题,科学家们仍然莫衷一是、不置可否。事实上,细菌感染引起的炎症已经成为致癌因素的最大嫌疑! 昨天,Science以快报(Express)形式发表了英、美、加等国科学家的最新研究成果,探讨大肠杆菌性肠炎与结肠癌及直肠癌的关系,论文题目是“肠炎指向微生物群落的癌症诱导活性”(I ntestinal Inflammation Targets Cancer-Inducing Activity of the Microbiot a)。 为此,ScienceDaily还专门配发了一篇最新评论和背景性介绍,文章的题目是“炎症、细菌群落与癌症的确凿关系被发现”(C lear Links Found Between Inflammation, Bacterial Communities and Canc er)。 这篇文章的新意在于不仅证实了大肠杆菌感染与结直肠癌的关系,而且首次发现只有含“基因毒性岛”(genotoxic island)的大肠杆菌才能诱发结直肠癌。也就是说,过去认为只要是慢性炎症就能致癌的观点不全面,因此为特殊病原体所致炎症才能致癌的观点提供了新证据。 所谓“基因毒性岛”是指大肠杆菌基因组中的聚酮合酶基因(pks)编码序列。最新研究发现,如果把这个pks基因删除掉,尽管肠炎依旧,但致癌性和侵润性减弱。 因此,结直肠癌归根结底还是由肠道细菌感染产生的聚酮类化合物诱发的。不过,聚酮合酶及聚酮类化合物如何参与炎症向癌症的转化还不清楚。 这个实验是在一种特殊的小鼠中完成的,它们的抗炎症细胞因子——白细胞介素10基因被敲除,从而导致肠道菌群改变,大肠杆菌菌株占绝对优势,使偶氮甲烷处理小鼠的侵润性结直肠癌发生率大增。 在另一项研究中还发现,这种pkc+大肠杆菌属于肠粘膜结合细菌,它们在炎性肠病(IBD)及肠炎相关结直肠癌(CRC)患者肠道中所占比例极高。这个结果印证了在小鼠中得出的上述结论。 在正常人中,pkc+毒性大肠杆菌仅有20%,IBD患者体内的毒性大肠杆菌则占40%,而结直肠癌患者体内的毒性大肠杆菌高达66.7%。同时,毒性大肠杆菌占优势的肠道中,非毒性菌群(如粪肠球菌)的比例同步减少。 关于这篇文章的意义,如果要给科学网的读者说得更浅显一点,那就是请大家记住以下三个要点: 一是免疫力低下的人群(如老人)经常腹泻或排便不正常一定要引起足够的重视,以防慢性肠炎最终发展成为结直肠癌; 二是不要滥用抗生素,虽然抗生素能杀死细菌,但也很容易造成肠道菌群紊乱,运气不好就会让大肠杆菌占优势,很可能不幸成为癌症牺牲者; 三是肠道菌群破坏后,还是有补救措施的,那就是经常服用益生菌(如双歧杆菌),在有冷藏设备的大型药店都可以买到含益生菌的药片。 原文现在还无法弄到,下面是其摘要: Inflammation alters host physiology to promote cancer, as seen in colitis-associated colorectal cancer (CRC). Here, we identify the intestinal microbiota as a target of inflammation that impacts the progression of CRC. High-throughput sequencing revealed that inflammation modifies gut microbial composition in colitis-susceptible interleukin-10–deficient ( Il10 −/− ) mice. Monocolonization with the commensal Escherichia coli NC101 promoted invasive carcinoma in azoxymethane (AOM)–treated Il10 −/− mice. Deletion of the polyketide synthase (pks) genotoxic island from E. coli NC101 decreased tumor multiplicity and invasion in AOM/ Il10 −/− mice, without altering intestinal inflammation. Mucosa-associated pks+ E. coli were found in a significantly high percentage of inflammatory bowel disease and CRC patients. This suggests that in mice, colitis can promote tumorigenesis by altering microbial composition and inducing the expansion of microorganisms with genotoxic capabilities.
文献分析结果 http://www.gopubmed.org/web/gopubmed/1?WEB01qc7z5ow6e238I2dI3pI00h001000j100200010 All colonoscopy and interval cancer Colorectal Neoplasms 635 of 20,903 documents semantically analyzed top author statistics 1 2 Top Years Publications 2009 64 2006 64 2008 63 2007 51 2005 50 2004 43 2010 42 2003 36 2001 27 2002 26 1995 26 2000 21 1999 21 1996 15 1998 13 1993 12 1997 11 1994 9 1992 7 1988 7 1 2 1 2 3 Top Countries Publications USA 312 United Kingdom 48 Japan 36 South Korea 24 Italy 21 Netherlands 20 Germany 19 France 19 Australia 18 Canada 16 Norway 10 Israel 9 Denmark 8 Taiwan 8 China 5 Sweden 5 Spain 4 Switzerland 4 Belgium 3 Hong Kong 3 1 2 3 1 2 3 ... 11 Top Cities Publications New York 22 Seoul 19 Boston 19 Indianapolis 18 Bethesda 17 Seattle 16 Chapel Hill 15 Minneapolis 12 Pittsburgh 12 Heidelberg 11 Los Angeles 11 Fukuoka 11 Cleveland 11 London 9 Rome 9 Toronto 9 Tucson 8 Portland 7 Ann Arbor 7 Oakland 7 1 2 3 ... 11 1 2 3 ... 10 Top Journals Publications Gastroenterology 43 Am J Gastroenterol 41 Cancer Epidem Biomar 35 Dis Colon Rectum 34 Clin Gastroenterol Hepatol 25 Gut 23 Am J Epidemiol 18 Cancer 17 J Natl Cancer I 14 New Engl J Med 14 Arch Intern Med 13 Gastrointest Endosc 12 Cancer Cause Control 12 J Clin Gastroenterol 10 J Natl Cancer Inst 9 Jama 9 Scand J Gastroentero 9 N Engl J Med 8 Endoscopy 8 Br J Surg 8 1 2 3 ... 10 1 2 3 ... 85 Top Terms Publications Humans 612 Colonoscopy 568 Colorectal Neoplasms 528 Middle Aged 491 Confidence Intervals 431 Aged 423 Patients 400 Adenoma 329 Adult 266 Odds Ratio 262 Risk Factors 228 Colonic Neoplasms 187 Evaluation Studies as Topic 181 Mass Screening 180 Sigmoidoscopy 170 Diagnosis 157 Incidence 156 Aged, 80 and over 156 Neoplasms 138 Colonic Polyps 128 1 2 3 ... 85 1 2 3 ... 160 Top Authors Publications Sandler R 19 Bond J 17 Haile R 16 Rex D 14 Neugut A 13 Weissfeld J 12 Schatzkin A 10 Waye J 10 Potter J 10 Newcomb P 10 Schn R 10 Bostick R 10 Lieberman D 9 Baron J 9 Giovannucci E 9 Levin T 8 Church T 8 Forde K 8 Lee E 8 Frankl H 8 1 2 3 ... 160 最新研究进展 N Engl J Med. 2010 May 13;362(19):1795-803. Quality indicators for colonoscopy and the risk of interval cancer. Kaminski MF , Regula J , Kraszewska E , Polkowski M , Wojciechowska U , Didkowska J , Zwierko M , Rupinski M , Nowacki MP , Butruk E . Department of Gastroenterology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland. Abstract BACKGROUND: Although rates of detection of adenomatous lesions (tumors or polyps) and cecal intubation are recommended for use as quality indicators for screening colonoscopy, these measurements have not been validated, and their importance remains uncertain. METHODS: We used a multivariate Cox proportional-hazards regression model to evaluate the influence of quality indicators for colonoscopy on the risk of interval cancer. Data were collected from 186 endoscopists who were involved in a colonoscopy-based colorectal-cancer screening program involving 45,026 subjects. Interval cancer was defined as colorectal adenocarcinoma that was diagnosed between the time of screening colonoscopy and the scheduled time of surveillance colonoscopy. We derived data on quality indicators for colonoscopy from the screening program's database and data on interval cancers from cancer registries. The primary aim of the study was to assess the association between quality indicators for colonoscopy and the risk of interval cancer. RESULTS: A total of 42 interval colorectal cancers were identified during a period of 188,788 person-years. The endoscopist's rate of detection of adenomas was significantly associated with the risk of interval colorectal cancer (P=0.008), whereas the rate of cecal intubation was not significantly associated with this risk (P=0.50). The hazard ratios for adenoma detection rates of less than 11.0%, 11.0 to 14.9%, and 15.0 to 19.9%, as compared with a rate of 20.0% or higher, were 10.94 (95% confidence interval , 1.37 to 87.01), 10.75 (95% CI, 1.36 to 85.06), and 12.50 (95% CI, 1.51 to 103.43), respectively (P=0.02 for all comparisons). CONCLUSIONS: The adenoma detection rate is an independent predictor of the risk of interval colorectal cancer after screening colonoscopy. 2010 Massachusetts Medical Society PMID: 20463339 Publication Types, MeSH Terms Publication Types: Research Support, Non-U.S. Gov't MeSH Terms: Adenoma/diagnosis* Adult Aged Clinical Competence* Colonic Polyps/diagnosis* Colonoscopy/standards* Colorectal Neoplasms/diagnosis* Early Detection of Cancer/standards Humans Middle Aged Multivariate Analysis Poland Proportional Hazards Models Quality Indicators, Health Care* Risk Factors LinkOut - more resources Full Text Sources: HighWire Press Ovid Technologies, Inc. Swets Information Services Medical: Benign Tumors - MedlinePlus Health Information Colonic Polyps - MedlinePlus Health Information Colonoscopy - MedlinePlus Health Information Colorectal Cancer - MedlinePlus Health Information Endoscopy - MedlinePlus Health Information 相关文献 Related citations Variation in polyp detection rates at screening colonoscopy. Gastrointest Endosc. 2009 Jun; 69(7):1288-95. Variations between endoscopists in rates of detection of colorectal neoplasia and their impact on a regional screening program based on colonoscopy after fecal occult blood testing. Gastrointest Endosc. 2010 Feb; 71(2):335-41. Epub 2009 Nov 17. Five-year risk of colorectal neoplasia after negative screening colonoscopy. N Engl J Med. 2008 Sep 18; 359(12):1218-24. Review Dtsch Med Wochenschr. 2008 Nov; 133(47):2458-62. Epub 2008 Nov 12. Review Colonoscopy: a review of its yield for cancers and adenomas by indication. Am J Gastroenterol. 1995 Mar; 90(3):353-65. See reviews... | See all...