Circular RNAs (circRNAs) are covalently closed circular structures without 5′ caps and 3′ tails, which are mainly formed from precursor mRNAs (pre-mRNAs) via back-splicing of exons. With the development of RNA sequencing and bioinformatic analysis, circRNAs were recently rediscovered and found to be widely expressed in the tree of life. Cerebellar degeneration-related protein 1 antisense RNA (CDR1as) is recognized as one of the most well-identified circRNAs. It contains over 70 miR-7 binding sites and can regulate gene activity by sponging miR-7. Increasing numbers of studies have recently demonstrated that CDR1as is abnormally expressed in many types of tumors, such as colorectal cancer, cholangiocarcinoma and osteosarcoma, and plays a vital role in the development of cancer. However, there are few reviews focusing on CDR1as and cancer. Hence, it is important to review and discuss the role of CDR1as in cancer. Here, we first review the main biological features of CDR1as. We then focus on the expression and roles of CDR1as in cancer. Finally, we summarize what is known on the role of CDR1as in cancer and discuss future prospects in this area of research.

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Targeting protein for Xenopus kinesin‐like protein 2 (TPX2) is a microtubule‐associated protein that plays a pivotal part in the formation of spindles. There is accumulating evidence that the expression of TPX2 is upregulated in many kinds of human cancers and that this protein is involved in the occurrence and progression of tumors. The purpose of this meta‐analysis was to investigate the relationship between the overexpression of TPX2 and poor prognosis in cancer patients. A total of 18 eligible studies encompassing 3115 patients were included by searching relevant databases. Hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were pooled under random‐/fixed‐effect models. After calculation, the results showed that patients with increased TPX2 expression had a significantly shorter overall survival (HR = 2.21; 95% CI: 1.70–2.86), and disease‐free survival (HR = 2.10; 95% CI: 1.67–2.64). In addition, it was found that increased TPX2 expression was significantly associated with TNM stage (OR = 2.17; 95% CI:1.42–3.32), lymph node metastasis (OR = 2.98; 95% CI: 2.28–3.89), distant metastasis (OR = 2.25; 95% CI:1.03–4.92), and vascular invasion (OR = 2.22; 95% CI:1.26–3.91). Nevertheless, there was no significant correlation between increased expression of TPX2 and either gender, tumor differentiation, or tumor size. Thus, we can come to the conclusion that the overexpression of TPX2 is related to poor clinical outcomes and can be used as a biomarker for the prognosis of patients with cancer.

Background : MicroRNAs are small non-coding RNAs containing 18-22 nucleotides which play a role in RNA silencing and post-transcriptional regulation of their target genes. The MiR-200 family comprises miR-141, miR-200a, miR-200b, miR-200c and miR-429. Increasing evidence indicates that miR-200 microRNAs play a role in cancer metastasis. For example, miR-200 microRNAs were reported to influence the prognosis in colorectal cancer patients by regulating the expression of genes related to the epithelial-mesenchymal transition 6 . Previous studies have shown that the high expression of miR-200 microRNAs has an impact on the overall survival and Relapse-free Survival of CRC patients. However, the study results were inconsistent. Results : Data from a total of 1882 patients from 9 studies was included in the meta-analysis. Poorer Relapse-free Survival (RFS) was observed in patients with high expression levels of miR-200 microRNAs (HR=1.13, 95% CI 1.04-1.23). Additionally, subgroup analysis of sample types revealed a significant association between higher expression of the miR-200 family in the plasma and poorer OS (HR=1.23, 95% CI 1.08-1.41) and RFS (HR=2.39, 95% CI 1.20-4.77), which indicates that the miR-200 family can be used as an easily detectable biomarker for evaluation of the prognosis of patients with colorectal cancer. Conclusions : High expression levels of miR-200 microRNAs were associated with poor clinical outcomes in colorectal cancer patients. The miR-200 family can therefore potentially serve as a prognostic biomarker. Further studies should be performed to verify the clinical utility of the miR-200 family in colorectal cancer.

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