Content area
Full Text
Introduction
Gastric cancer is the second leading cause of cancer-associated mortality worldwide due to its high incidence. Various inherited and environmental factors, including genetic characteristics, infectious agents and dietary habits serve an essential role in the development of gastric cancer (1). Furthermore, signaling pathways, including the epidermal growth receptor, vascular endothelial growth factor, phosphoinositide 3-kinase/protein kinase b/mechanistic target of rampamycin (PI3K/AKT/mTOR) and hepatocyte growth factor/hepatocyte growth factor receptor signaling pathways have been demonstrated as being associated with gastric cancer in a molecular classification study (2). Surgical resection and chemo-radiation are the most efficient strategies for treating gastric cancer (3). However, due to the lack of convenient, noninvasive biomarkers for routine population screening, diagnosis of early stage gastric cancer is challenging in the majority of patients (3). In addition, peritoneal dissemination and local metastases occur in the late stages of gastric cancer (3). A previous study suggested that microRNAs (miRNAs or miRs) are important regulators of the oncogenesis pathway and may be used as clinical biomarkers (4). The emergence of miRNAs serving as biomarkers has provided a novel method of diagnosing cancer and determining the prognosis for various types of cancer, including gastric cancer (3).
The mechanism of epigenetic regulation and control does not include sequence alteration of the coding gene and is important in post-translational regulation as an independent process (5). It is important in tumor formation and development, especially with the abnormal expression and dysfunction of miRNA, which is one of the components of the p53 tumor suppressor network (6,7). miR-34a is a member of the miRNA family, which has tumor suppressor properties, promotes apoptosis and cell arrest, and has an aging function (8). miR-34a has gradually drawn considerable attention due to its tumor suppressor effect. It serves an essential role as a tumor suppressor gene in many types of tumors through impacting various potential tumor associated genes, including sirtuin 1, SNAIL and zinc finger E-box-binding homeobox 1 (9,10). The present study aimed to compare the difference in expression of miR-34a between gastric adenocarcinoma and paired paricarcinomatous, various gastric cancer cells and gastric epithelial cells in order to determine the expression of miR-34a in human gastric cancer and whether miR-34a targets its downstream gene to affect the biological function of gastric cancer. A previous...