) is reported to be overexpressed in colorectal carcinoma (CRC), but the role of miR-191 in CRC progress remained unclear. This study demonstrated that High miR-191 expression was associated with clinical stage, lymph node metastasis, liver metastasis and depth of tumor invasion. Kaplan-Meier analysis indicated that patients with high miR-191 expression had a poor overall survival. Moreover, multivariate analysis showed that miR-191 was an independent prognostic factor in patients with CRC. Furthermore, we found that tissue inhibitor of metalloprotease 3 (TIMP3) was a direct target of miR-191 in colorectal cancer SW620 cells. TIMP3 downregulation mediated by miR-191 activated matrix metalloproteinases (MMPs) and thus promoted invasiveness of cancer cells. Anti-miR-191 could attenuate the invasiveness, suppress proliferation and induce apoptosis by restoring TIMP3 expression. Our results suggested that miR-191 might be a potential diagnostic and therapeutic target in patients with colorectal cancer.

Human cytomegalovirus infection (HCMV) has been recently considered as a factor for tumorigenesis. The current study used meta-analytical techniques to explore the prevalence of HCMV in tumor tissues and the relationship between human cytomegalovirus and colorectal cancer (CRC) risk. 11 studies detecting HCMV DNA in tumor tissues were included in meta-analysis. The prevalence rate and odds ratio (OR) were two main parameters. The overall prevalence of human cytomegalovirus DNA in tumor tissues were 27.5% (95% CI = 17.2%−37.8%). Binary logistic regression showed that the studies reported before 2010 involving formalin-fixed specimens from patients in developed region represented a lower proportion of HCMV. The tumor tissues had a significantly higher rate of virus infection compared with normal tissues (OR = 6.59, 95% CI = 4.48−9.69, I2 = 0%, P = 0.71). Subgroup analysis revealed the prevalence of the virus didn't differ in patients with different tumor stages, in tumor cells with different histologic grades, also in different kinds of specimen (polyp and adenocarcinoma). The results of current study suggested a statistically association between the virus infection and an increased risk of colorectal cancer.

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