Exosomal circular RNAs: A new frontier in the metastasis of digestive system tumors.

Exosomes are membrane vesicles with a diameter of 30-150 nm. Exosomes are secreted by various types of tumor cell and contain a variety of proteins, circular RNAs (circRNAs), microRNAs and DNA, depending on the host cells. Among them, circRNAs, which are long non-coding endogenous RNAs, form covalently closed and continuous loops that link the 3' and 5' terminals generated by back-splicing. circRNAs have become a hotspot of research. Exosomal circRNAs are in volved in the pathogenesis of cancer, especially metastasis, which is mainly ascribed to the frequently abnormal expression levels within neoplasms. Nonetheless, the functions and regulatory mechanisms of exosomal circRNAs in the progression of digestive system tumors (DSTs) remain unclear. More knowledge on the regulation and network interactions of exosomal circRNAs will help identify superior treatment strategies for the metastasis of DSTs. The present review aims to summarize the existing studies on the functions and mechanisms of exosomal circRNAs in tumorigenesis, and evaluate the associations between the dysregulation of exosomal circRNAs and tumor metastasis.

Effects of aspirin on the gastrointestinal tract: Pros vs. cons.

Acetylsalicylic acid, also known as aspirin, is often used in clinical antipyretic, analgesic and antiplatelet therapy. Aspirin can cause numerous side effects in the gastrointestinal (GI) tract, ranging from unpleasant GI symptoms without gastric mucosal lesions to ulcer bleeding and even death. However, recent studies have found that aspirin can significantly prevent GI tumors. Despite impressive advances in cancer research, screening and treatment options, GI tumors remain a leading cause of death worldwide. Prevention is a far better option than treatment for tumors. Therefore, the present review assesses the pros and cons of aspirin on the GI tract and, on this the basis, the appropriate dose of aspirin to protect it.

Zenker's diverticulum treated with submucosal tunneling endoscopic septum division surgery: Two case reports.

INTRODUCTION: Zenker's diverticulum (ZD) refers to a pouch-like structure similar to the esophageal lumen formed from the herniation of the esophageal mucosa; this structure makes it difficult for food to pass through the esophagus to the stomach. The development of endoscopic technology has made minimally invasive surgical treatments for ZD possible. PATIENT CONCERNS: A female 72-year-old patient was admitted to our hospital due to recurrent dysphagia for more than 5 years. A 62-year-old female patient underwent a gastroscopic examination due to recurrent dysphagia for 10 years and aggravated dysphagia accompanied by bad breath for 1 year. DIAGNOSIS: A significant diverticulum with food residue at the entrance of the esophagus was found on gastroscopy in both cases. INTERVENTIONS: After completing a relevant examination and excluding surgical contraindications, both patients underwent submucosal tunneling endoscopic septum division. OUTCOMES: Both patients were discharged after symptoms alleviated on postoperative day 4. A 3-month follow-up gastroscopy showed the disappearance of the diverticulum and recovery of the esophageal anatomical structure. No symptom relapse was found at the 6-month follow-up assessment. CONCLUSION: Submucosal tunneling endoscopic septum division has become the most common minimally invasive treatment option. It is efficient and safe for relieving symptomatic ZD in the short term.

Circular RNAs: an emerging landscape in tumor metastasis.

Circular RNAs (CircRNAs), the endogenous long noncoding RNAs, unlike linear RNAs, are structurally continuous, covalently closed loops without 5' cap or 3' polyadenylated tail. High-throughput RNA sequencing has enabled the discovery of several endogenous circRNAs in different species and tissues. The circRNAs mainly act as sponges to cytoplasmic microRNA, aid in protein translation, or interact with RNA-binding proteins to generate RNA-protein complexes which control transcription. Recently, circRNAs have been reported to participate in cancer pathogenesis, particularly tumor metastasis in humans, mainly due to their frequent aberrant expression in cancers. However, the detail molecular mechanism of circRNAs activity in tumor metastasis is still elusive. Some specifically expressed circRNAs can potentially be used as biomarkers and therapeutic targets for tumor treatment. Further understanding of the network interactions and regulation of circRNAs is paving the way for the identification of better therapeutic strategies in tumor metastasis. In this mini review, we have summarized the current state of research on functions and mechanisms of novel circRNAs that regulate tumorigenesis and have evaluated the relationship between dysregulation of circRNAs and tumor metastasis.