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Background Gut microbiota dysbiosis involved in the pathogenesis of colorectal cancer (CRC). The characteristics of enterotypes in CRC development have not been determined. Objective To characterize the gut microbiota of healthy, adenoma, and CRC subjects based on enterotype. Methods The 16 S rRNA sequencing data from 315 newly sequenced individuals and three previously published datasets were collected, providing total data for 367 healthy, 320 adenomas, and 415 CRC subjects. Enterotypes were analyzed for all samples, and differences in microbiota composition across subjects with different disease states in each enterotype were determined. The predictive values of a random forest classifier based on enterotype in distinguishing healthy, adenoma, and CRC subjects were evaluated and validated. Results Subjects were classified into one of three enterotypes, namely, Bacteroide- (BA_E), Blautia- (BL_E), and Streptococcus- (S_E) dominated clusters. The taxonomic profiles of these three enterotypes differed among the healthy, adenoma, and CRC cohorts. BA_E group was enriched with Bacteroides and Blautia; BL_E group was enriched by Blautia and Coprococcus; S_E was enriched by Streptococcus and Ruminococcus. Relative abundances of these genera varying among the three human cohorts. In training and validation sets, the S_E cluster showed better performance in distinguishing among CRC patients, adenoma patients, and healthy controls, as well as between CRC and non-CRC individuals, than the other two clusters. Conclusion This study provides the first evidence to indicate that changes in the microbial composition of enterotypes are associated with disease status, thereby highlighting the diagnostic potential of enterotypes in the treatment of adenoma and CRC. Keywords: Enterotype, Adenoma, Colorectal cancer, Gut microbiota, Random forest model, Author(s): Li Qingbo[sup.1], Zhuang Jing[sup.1,2,3], Qu Zhanbo[sup.1,2,3], Chu Jian[sup.1,2,3], Song Yifei[sup.1], Wu Yinhang[sup.1,2,3] and Han Shuwen[sup.1,2,3] Introduction The human gastrointestinal tract is inhabited by a community of approximately 100 trillion [...]

Gastrointestinal (GI) cancers are among the most common and lethal cancers worldwide. GI microbes play an important role in the occurrence and development of GI cancers. The common mechanisms by which GI microbes may lead to the occurrence and development of cancer include the instability of the microbial internal environment, secretion of cancer-related metabolites, and destabilization of the GI mucosal barrier. In recent years, many studies have found that the relationship between GI microbes and the development of cancer is closely associated with the GI redox level. Redox instability associated with GI microbes may induce oxidative stress, DNA damage, cumulative gene mutation, protein dysfunction and abnormal lipid metabolism in GI cells. Redox-related metabolites of GI microbes, such as short-chain fatty acids, hydrogen sulfide and nitric oxide, which are involved in cancer, may also influence GI redox levels. This paper reviews the redox reactions of GI cells regulated by microorganisms and their metabolites, as well as redox reactions in the cancer-related GI microbes themselves. This study provides a new perspective for the prevention and treatment of GI cancers. Keywords: Gastrointestinal microbes, Gastrointestinal cancers, Redox, Reactive oxygen species, Oxidative stress, Author(s): Wang Yangyanqiu[sup.1,2,4], Chu Jian[sup.1,3,4], Yang Yuqing[sup.1,4], Qu Zhanbo[sup.1,3,4] and Han Shuwen[sup.1,4] Introduction According to Global Cancer Statistics 2020, gastrointestinal (GI) cancers, including colorectal cancer and gastric cancer, account for [...]