Abstract

Noncoding genomics, i.e., microRNAs and long coding RNAs (lncRNA), is an emerging topic in gastrointestinal tumors. In particular, the coordinate deregulation of miRNA-335-5p across these tumors and its potential clinical applications is an example of this scenario. This chapter discusses the pathogenetic role of miRNA-335-5p in esophageal, gastric, colon, liver, gallbladder, and pancreatic tumors. This pathogenetic role is examined in the context of the competing endogenous network, the language through lncRNA that reduce the quantity of miRNA available to target mRNA. The translational application of miRNA-335-5p, through the aberrant methylation of the promoter region of MEST—its host gene—as a potential biomarker for noninvasive detection of gastric cancer, is also discussed.