The association between colorectal cancer and gut microbiota imbalance has became a hot research topic along with the increase of its irevalance.In this article, we search for the potential specific carcinogenic strainand their metabolite markers in the development of colorectal cancer, with an attempt to provide an important basisfor early diagnosis and primary prevention of colorectal cancer, elucidate the potential roles and mechanisms of in-testinal microbioecological preparation and improve the management of colorectal cancer.

Objective:To investigate the correlation of human epidermal growth receptor 2 (HER2) with clinicopathological characteristics and its postoperative prognostic value in patients with gastric cancer.Methods:The clinicopathological data of 543 patients with gastric cancer who underwent open radical gastrectomy were retrospectively analyzed in the Gastrointestinal Surgery Department of Jiangyin People′s Hospital Affiliated to Southeast University from June 2011 to December 2016, including 404 males and 139 females, aged from 26 to 84 years old. According to the results of HER2 immunohistochemical staining, gastric cancer patients were divided into HER2 0+ group ( n=427), HER2 1+ group ( n=56), HER2 2+ group ( n=29) and HER2 3+ group ( n=31), and the differences in clinicopathological indicators of the four groups were compared. Furthermore, HER2 0+ and 1+ gastric cancer patients were classified as HER2-negative group( n=26), and HER2 3+ as HER2-positive group( n=26). Propensity score matching method was used to balance the basic data variables related to prognosis of the two groups, and Kaplan-Meier method was used for survival analysis. Cox risk regression model was used to analyze the risk factors associated with postoperative survival in patients with HER2-positive gastric cancer. Results:The overexpression rate of HER2 in gastric cancer patients was 5.7% (31/543). The expression level of HER2 was significantly correlated with gender ( χ2=8.30, P=0.040), tumor longitudinal location ( χ2=22.86, P=0.029) and histological differentiation ( χ2=13.27, P=0.004). There was no significant correlation between median survival time and HER2 expression level( χ2=5.44, P=0.142). After propensity score matching, the median survival time of gastric cancer in the HER2-positive group was 23 months. Univariate and multivariate analysis showed that ABO blood group ( HR: 1.619, 95% CI: 1.081-2.423, P=0.019) was an independent risk factor for prognosis of HER2-positive gastric cancer. Conclusion:The expression of HER2 is higher in men, cardia fundus and high and medium differentiated gastric adenocarcinoma, but there is no significant correlation between the expression level of HER2 and the median survival time of gastric cancer. ABO blood group may be an independent risk factor for the survival of HER2-positive gastric cancer.