ABSTRACT
Gastric cancer is the second most common cause of cancer-related death in the world, and it remains diffi cult to cure worldwide, because most patients present advanced disease (Danaei et al. 2005). Although recent advances have been made, surgery still remains to be the most effective treatment for gastric cancer patients. However, patients with locally advanced disease show high rates of distant recurrence even after potentially curative resections (Scartozzi et al. 2010). Even patients who present the most favorable condition and who undergo curative surgical resection often die of recurrent disease. The 5-year survival rate for curative surgical resection ranges from 30% to 50% for patients with stage II disease or stage III disease, respectively (Lee et al. 2009). Stomach cancer can metastasize to the esophagus or the small intestine, and can extend through the stomach wall to nearby lymph nodes and organs such as liver, pancreas, and colon (Zheng et al. 2003). In the past decades, studies have focused on investigating the molecular mechanism underlying the development and progression of gastric cancer. The progression is thought to involve the deregulation of genes that are critical to cellular processes such as cell cycle control, cell growth, apoptosis, metastasis and invasion (Wang et al. 2008). Recently, an increasing number of reports have described a new class of small regulatory RNA molecules termed microRNAs (miRNAs) that are implicated in gastric cancer development (Ueda et al. 2010). Moreover, compelling evidence demonstrates that miRNAs have important roles in gastric cancer progression and directly contribute to the cell proliferation, avoidance of apoptosis, and metastasis of gastric cancer (Wu et al. 2010b). miRNA carries out its biological functions by repressing or activating the expression of its target genes through base-pairing with endogenous mRNAs. In this consideration, miRNA genes have been characterized as novel proto-oncogenes or tumor suppressors in gastric carcinogenesis. Identifying the miRNAs and their targets that are essential for gastric cancer progression may provide promising therapeutic opportunities. In this review, we discuss recent advances in our knowledge of miRNAs and validated targets in gastric cancer progression and the potential future perspectives.
